Vitamins & Supplements · Omega fatty acid

Omega-6 fatty acids

Q: What are omega-6 fatty acids?

They are essential polyunsaturated fats. Linoleic acid is the main one in food, and the body can make arachidonic acid from it. The NHS says most people get enough omega-6.

Q: Which foods have omega-6?

The NHS names rapeseed, corn and sunflower oils and walnuts, almonds and cashews. By USDA data, a tablespoon of soybean oil has about 6.9 g of linoleic acid and an ounce of almonds about 3.5 g.

Q: Is omega-6 inflammatory?

Arachidonic acid, made from linoleic acid, is the parent of some inflammatory signals. But two reviews of randomised trials in adults found no significant rise in inflammation blood markers with more linoleic acid.

Q: Is omega-6 bad for the heart?

Cohort studies link higher linoleic acid to less heart disease. Trials gave mixed results: Cochrane found little or no difference in deaths or events, and one old Sydney trial found more deaths. It does not clearly harm or protect.

Q: Does omega-6 lower cholesterol?

A little. In 10 trials, total cholesterol fell about 0.33 mmol/L. LDL, HDL and triglycerides changed little or not at all. The Minnesota trial lowered cholesterol but not deaths.

Q: Does omega-6 raise the risk of cancer or bowel disease?

Observational studies are mixed. The highest dietary linoleic acid intakes were linked to colorectal cancer (RR 1.15) and ulcerative colitis, but tissue levels were not linked to colorectal cancer, and these studies cannot show cause.

Q: Does omega-6 affect diabetes?

In 20 cohorts, higher linoleic acid in the blood was linked to a lower chance of developing type 2 diabetes (RR 0.65). Arachidonic acid showed no link. This is observational.

Q: Do vegans lack arachidonic acid?

A 2025 position paper says healthy adults, and pregnant and breastfeeding women, can make arachidonic acid from linoleic acid and do not need supplements. Infants should be breastfed or given formula that contains it.

Q: Do arachidonic acid supplements build muscle?

One small trial in 19 trained men found no change in muscle protein synthesis after exercise. It raised some inflammation signals briefly without worse soreness. The evidence is insufficient.

Q: Is omega-6 safe in pregnancy?

No safety trial of omega-6 supplements in pregnancy was read. The 2025 position paper says pregnant women can make arachidonic acid from linoleic acid. Ask a doctor or midwife.

Linoleic acid (18:2 n-6) and arachidonic acid (20:4 n-6) · also called Omega-6 fats, LA, ARA, ácidos grasos omega-6

Omega-6 fats are essential fats found in vegetable oils, nuts and seeds. Linoleic acid is the main one, and the body makes arachidonic acid from it. Most people get enough from food. Studies show a small fall in total cholesterol, mixed results for heart disease, and no clear rise in inflammation markers. Ask a doctor or pharmacist before using a supplement.

General information, not medical advice. Last substantive update October 26, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Omega-6 fatty acids

Omega-6 fats are the other essential fat family next to omega-3. They come mainly from vegetable oils, nuts and seeds. The research mixes strong findings (a small cholesterol fall) with unsettled ones (heart events, cancer, bowel disease).

What omega-6 fats are

Linoleic acid (LA) is the main omega-6 fat in food. The NHS says some omega-3 and omega-6 fats cannot be made by the body, so small amounts are essential, and that most people get enough omega-6. Arachidonic acid (ARA) is a longer omega-6 fat. A 2025 position paper says it is almost absent from plant foods and that healthy adults can make it from linoleic acid.

Gamma-linolenic acid (GLA) is another omega-6 fat sold as evening primrose or borage oil. It has its own page.

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Where omega-6 fats are found

The NHS lists rapeseed, corn and sunflower oils, and walnuts, almonds and cashews. USDA data (SR Legacy, 2018) give linoleic acid per portion of about 6.9 g in a tablespoon of soybean oil, 7.2 g in corn oil, 2.6 g in canola oil, 8.2 g in 3 tablespoons of hulled hemp seed, 3.5 g in an ounce of almonds and 2.7 g in an ounce of dry-roasted peanuts. These are food facts, not advice on how much to eat.

The American Heart Association, as summarised in a 2010 review, gave an approximate healthy target of 15 g a day of linoleic acid (12 g for women, 17 g for men). Food is the source in nearly all studies.

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What the research shows

The firmest finding is a small fall in total cholesterol when omega-6 replaces other fats. Big cohort studies link higher linoleic acid to less heart disease and type 2 diabetes. But trials that changed diets found little or no difference in deaths or cardiovascular events, and two re-analyses of old trials found no benefit. In the Sydney trial, men on an omega-6 oil swap had more deaths.

For inflammation, two systematic reviews of randomised trials found no significant rise in blood markers with more linoleic acid. A 2025 review says the pro-inflammatory idea began as a hypothesis.

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Omega-6 and omega-3 together

The AHA, as summarised in a 2010 review, says Americans need to increase long-chain omega-3 while maintaining omega-6. See the pages on the omega-6 to omega-3 ratio and on omega-3 oils for more.

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Quality of oils and supplements

Rancidity, heated oils and the accuracy of arachidonic acid supplement labels were not researched here. No source read tested heated oils in people.

At a glance

Traditional uses history, not proof

Eaten for centuries in nuts, seeds and their oils as everyday dietary fats
Promoted from the 1960s as a way to lower cholesterol by swapping out saturated fat

Studied for research

Essential food nutrient, high certainty
Total cholesterol, small fall, high certainty
Inflammation markers, no clear rise, moderate certainty
Heart disease in cohort studies, low certainty
Heart disease in trials, mixed
Type 2 diabetes, low certainty
Cancer, ulcerative colitis, muscle and arachidonic acid supplements, very low or insufficient

Main compounds

Linoleic acid (LA)
Arachidonic acid (ARA)
Gamma-linolenic acid (GLA)

Common forms

Vegetable oils (soybean, corn, canola, sunflower)
Nuts and seeds
Arachidonic acid capsules (small trials only)

Research links: 2018 Cochrane review: omega-6 fats for heart disease (19 trials) · 2014 meta-analysis: dietary linoleic acid and coronary heart disease · 2017 review: linoleic acid and blood inflammation markers · 2013 BMJ: Sydney Diet Heart Study recovered data · NHS: Fat, the facts · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Omega-6 fatty acids (mainly linoleic acid, 18:2 n-6, and its product arachidonic acid, 20:4 n-6)
Common names: Omega-6 fatty acids (English); Linoleic acid (LA) (English); Arachidonic acid (ARA or AA) (English); Ácidos grasos omega-6, ácido linoleico, ácido araquidónico (Spanish)
Family or group: Polyunsaturated fatty acids. The NHS says there are two main types, omega-3 and omega-6.
Harvest and processing: Not described in the sources read.
Look-alikes and adulterants: Name: Omega-3 fats (ALA, EPA, DHA); Note: The other essential fat family. Fish oil, algal oil and flax oil have their own pages.; Name: Gamma-linolenic acid (GLA); Note: Another omega-6 fat sold as evening primrose, borage or blackcurrant seed oil. It has its own page.; Name: Omega-9 (oleic acid); Note: A different fat family that the body can make. It has its own page.; Name: Conjugated linoleic acid (CLA); Note: A different sold product that is not covered on this page.
Sustainability and conservation: Not assessed.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
Late 1960s and 1970s	Diet trials in Sydney (1966 to 1973) and Minnesota (1968 to 1973) replaced saturated fat with linoleic-acid-rich vegetable oils to lower cholesterol and heart disease. Decades later, researchers recovered and re-analysed the lost data (2013 and 2016).	p23386268
Minnesota Coronary Experiment, 1968 to 1973	The trial tested a corn oil diet in a nursing home and six state mental hospitals; it lowered cholesterol but showed no benefit for deaths.	p27071971
2009 to 2010	The American Heart Association published a science advisory on omega-6 fats (2009). A 2010 review notes there were calls in the popular press to cut omega-6 fats because of presumed proinflammatory and prothrombotic effects.	p20145438
2025	A review traces the controversy: omega-6 oils were first promoted for lowering cholesterol, then questioned for proposed pro-inflammatory and oxidative effects, leading to inconsistent guidelines.	p41613930

Traditional use shows how it was used. It does not show that it works or is safe today.

What is inside, and how it may work

What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Linoleic acid (LA, 18:2 n-6)	omega-6 polyunsaturated fatty acid	Vegetable oils, nuts and seeds USDA per 100 g: soybean oil 50.4 g, corn oil 53.2 g, hemp seed 27.4 g, canola oil 18.6 g, almonds 12.3 g, dry-roasted peanuts 9.7 g.	Essential in the diet. The predominant omega-6 fat. The body can make arachidonic acid from it. ^{23 21 2}	Human data
Arachidonic acid (ARA or AA, 20:4 n-6)	omega-6 polyunsaturated fatty acid	Almost absent from plant foods No food content values were read.	Made from linoleic acid by healthy adults; a precursor of prostaglandins and other eicosanoids. ^{18 12}	Human data
Gamma-linolenic acid (GLA) and dihomo-gamma-linolenic acid (DGLA)	omega-6 polyunsaturated fatty acid	Not described in the sources read	Seven of the 19 trials in the Cochrane review supplemented GLA; none supplemented DGLA or arachidonic acid. ⁶	Human data

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Conversion of linoleic acid to arachidonic acid	Not described in the sources read (FADS gene variants did not significantly change results in two pooled analyses)	Healthy adults and pregnant and lactating women can make arachidonic acid from linoleic acid, according to a 2025 position paper. ^{18 19}	Human data
Prostaglandins and other eicosanoids	Not described in the sources read	Arachidonic acid is a precursor to prostaglandins with possible roles in muscle growth; eicosanoids also have pro-inflammatory actions (trial authors). In the trial, ARA supplements did not change muscle protein synthesis. ^{12 11}	Human data
Inflammation	Not described in the sources read	Two systematic reviews of randomised trials found no significant effect of higher dietary linoleic acid on inflammatory blood markers in adults; the concern about pro-inflammatory effects is described as a hypothesis in a 2025 review. ^{8 17 2}	Human data
Cholesterol lowering	Not described in the sources read	Replacing saturated fat with omega-6 lowers total cholesterol a little (Cochrane, high quality); in Minnesota it lowered cholesterol without lowering deaths. ^{6 15}	Human data

Absorption, metabolism and elimination

Absorption: Not described in the sources read.
Distribution: An arachidonic acid supplement (1.5 g a day for 4 weeks) raised arachidonic acid in plasma and in skeletal muscle phospholipids in 19 trained men.
Metabolism: Healthy adults can make arachidonic acid from linoleic acid (position paper).
Elimination: Not described.
Bioavailability: Not described beyond the plasma and muscle rise above.

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Isolated compounds versus whole extracts

Linoleic acid in food comes with other nutrients: nuts and seeds bring fibre, protein and minerals, and oils bring other fats. Trials of "omega-6" mostly swapped whole-diet fats, not capsules. Arachidonic acid supplements are a different thing again and were tested only in 19 trained men. No trial compared linoleic acid foods with capsules.

Nutritional composition

USDA FoodData Central SR Legacy (April 2018), read 2026-10-26 from saved local copies of the records. Linoleic acid 18:2 per 100 g and per household portion: soybean oil (FDC 171411) 50.418 g, about 6.9 g per tablespoon (13.6 g); corn oil (171029) 53.23 g, about 7.2 g per tablespoon (13.6 g); canola oil (172336) 18.64 g, about 2.6 g per tablespoon (14 g); hulled hemp seed (170148) 27.358 g, about 8.2 g per 3 tablespoons (30 g); almonds (170567) 12.32 g, about 3.5 g per ounce (28.35 g); dry-roasted peanuts without salt (173806) 9.694 g, about 2.7 g per ounce. Sunflower oil, safflower oil, walnuts and sunflower seeds had no linoleic acid line in the saved copy. These are nutrient facts about foods, not advice on how much to eat.

11benefits and uses looked at

23studies and sources checked

High certaintybest evidence rating found

7lab markers tracked in trials

2 high certainty1 moderate certainty1 mixed findings3 low certainty3 very low certainty1 not enough evidence

What was looked at

The 11 benefits and uses checked for Omega-6 fatty acids, each with how strong the evidence is. Tap one to open it.

An essential fat that comes from foodHigh certainty
Heart disease risk: what large observational studies foundLow certainty
Heart disease events in trials that replaced saturated fat with omega-6Mixed findings
Blood cholesterol when omega-6 replaces other fatsHigh certainty
Inflammation: does more linoleic acid raise inflammatory markers?Moderate certainty
Type 2 diabetes risk (blood-level link)Low certainty
Cancer overall (umbrella of cohort studies)Very low certainty
Colorectal cancer risk (a possible harm signal)Very low certainty
Ulcerative colitis risk (a possible harm signal)Very low certainty
Arachidonic acid supplements and muscle response to exerciseNot enough evidence
Arachidonic acid in plant-based diets and infancyLow certainty

Lab markers tracked in the studies

Total cholesterolLDL, HDL and triglyceridesInflammation blood markers (CRP, IL-6, TNF)Linoleic acid level in blood and fat tissueLinoleic acid level in blood and diabetes riskArachidonic acid in plasma and muscleInflammation after a hard exercise session

What is Omega-6 fatty acids good for?

The main studied uses and how strong the human evidence is for each. Most results are about omega-6 from food or blood levels; only arachidonic acid has been tried as a capsule, in one small trial.

An essential fat that comes from foodHigh certaintyLinoleic acid cannot be made by the body, so it comes from food. The NHS says most people get enough. By USDA data, one tablespoon of soybean oil has about 6.9 g, corn oil about 7.2 g, canola oil about 2.6 g and one ounce of almonds about 3.5 g. Total cholesterolHigh certaintyIn 10 trials (4,280 people), more omega-6 lowered total cholesterol by about 0.33 mmol/L, usually replacing saturated fat. LDL, HDL and triglycerides changed little or not at all. Inflammation blood markersModerate certaintyTwo reviews of randomised trials in adults found no significant change in CRP, IL-6, TNF or other markers with more linoleic acid. One analysis hints that a very large increase might raise CRP. Heart disease risk in cohort studiesLow certaintyLarge pooled studies link higher linoleic acid intake to 15% lower coronary events and higher blood levels to lower cardiovascular death. These are links, not proof. Heart disease events in trialsMixed findingsCochrane found little or no difference in deaths (RR 1.00) or cardiovascular events (RR 0.97). A review of 8 trials found 19% fewer coronary events when polyunsaturated fat replaced saturated fat. The recovered Sydney trial found more deaths. Type 2 diabetes riskLow certaintyPeople with higher linoleic acid in their blood were less likely to develop type 2 diabetes (RR 0.65). Arachidonic acid showed no link. Observational only. Cancer overallVery low certaintyA review of 150 publications linked higher omega-6 to lower overall cancer, but to higher ovarian and endometrial cancer. Results differ by cancer type. Colorectal cancer (a possible harm)Very low certaintyHighest dietary linoleic acid intake was linked to 15% higher colorectal cancer risk in 20 cohorts, but tissue levels were not. Ulcerative colitis (a possible harm)Very low certaintyIn one European study, the highest quartile of linoleic acid intake had more than double the odds of ulcerative colitis (OR 2.49). Only 126 cases. Arachidonic acid supplements for muscleNot enough evidenceIn 19 trained men, 4 weeks of arachidonic acid did not change muscle building after exercise. It raised some inflammation signals briefly. Arachidonic acid in plant-based diets and infancyLow certaintyA 2025 expert paper says healthy adults can make arachidonic acid from linoleic acid, while infants need breast milk or formula with it. Data are sparse.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

An essential fat that comes from food

High certainty

Linoleic acid is an omega-6 fat the body cannot make, so it has to come from food. The NHS says most people get enough omega-6 in their diet. Vegetable oils, nuts and seeds are the main sources. By USDA data, one tablespoon of soybean oil has about 6.9 g, one tablespoon of corn oil about 7.2 g and one ounce of almonds about 3.5 g of linoleic acid.

4 studiesFood sources. Supplement forms of linoleic acid are not described in …

Studies, doses and limits

What the trials found

The NHS lists omega-6 fats in rapeseed, corn and sunflower oils and in walnuts, almonds and cashews, and says most people get enough omega-6. USDA SR Legacy (April 2018) lists linoleic acid per 100 g at 50.4 g in soybean oil, 53.2 g in corn oil, 18.6 g in canola oil, 27.4 g in hulled hemp seed, 12.3 g in almonds and 9.7 g in dry-roasted peanuts. Per household portion that is about 6.9 g (1 tablespoon soybean oil, 13.6 g), 7.2 g (1 tablespoon corn oil, 13.6 g), 2.6 g (1 tablespoon canola oil, 14 g), 8.2 g (3 tablespoons hemp seed, 30 g), 3.5 g (1 ounce almonds) and 2.7 g (1 ounce dry-roasted peanuts). The AHA, as summarised in a 2010 review, gave an approximate linoleic acid intake of 15 g a day (12 g for women, 17 g for men) as the healthy target. Arachidonic acid is a different omega-6 fat that is almost absent from plant foods; the body can make it from linoleic acid.

Results

Linoleic acid is a real, essential dietary fat found in common oils, nuts and seeds. Nutrient content is a fact about the food, not a trial result, and varies by food and brand.

Effect sizes as reported

No effect size applies: these are nutrient contents.

Why this rating

High that these foods contain linoleic acid (NHS, USDA). This is not a trial result for any health outcome.

Form and dose studied

Food sources. Supplement forms of linoleic acid are not described in the sources read.

Who was studied

General population.

Limits

USDA numbers come from a saved copy of the 2018 SR Legacy records for one generic entry per food. Sunflower oil, safflower oil, walnuts and sunflower seeds had no linoleic acid line in the saved copy, so no number is given for them. The NHS page review date has passed (April 2026).

Why researchers looked

People ask where omega-6 fats come from and whether they need any extra.

Traditional use

Not described in the sources read.

Proposed mechanism Established nutrition

Some omega-6 and omega-3 fats cannot be made by the body, so small amounts are essential in the diet (NHS).

A proposed mechanism does not show that the effect happens in people.

No safety issue for ordinary food amounts was described in the sources read; see the Safety tab for the trial and cohort signals.

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Heart disease risk: what large observational studies found

Low certainty

Large pooled studies of people's diets and blood levels link higher linoleic acid to lower heart disease risk. This is a link, not proof that eating more linoleic acid prevents heart disease.

3 studiesDietary intake and blood levels; no supplement was studied.

Studies, doses and limits

What the trials found

A 2014 meta-analysis of 13 cohorts (310,602 people, 12,479 coronary events) found the highest versus the lowest linoleic acid intake linked to 15% lower coronary heart disease events (RR 0.85) and 21% lower coronary deaths (RR 0.79). A 2019 pooled analysis of 30 studies (68,659 people, 15,198 events) found higher blood or tissue linoleic acid linked to lower total cardiovascular disease (HR 0.93), cardiovascular death (HR 0.78) and ischemic stroke (HR 0.88); arachidonic acid levels were not linked to higher risk. A 2025 review of 150 publications of cohort studies reported lower cardiovascular disease and all-cause death with higher omega-6, with no protective link in people with existing conditions.

Results

People who eat more linoleic acid, or have more of it in their blood, had less heart disease. The studies are observational and cannot show cause.

Effect sizes as reported

Pooled RR 0.85 for coronary events; HR 0.78 for cardiovascular death.

Why this rating

Low (our rating): consistent observational links, but no randomised proof, and the 2019 analysis includes industry-linked authors.

Form and dose studied

Dietary intake and blood levels; no supplement was studied.

Who was studied

Adults in many countries; mostly people who eat ordinary diets.

Limits

Observational: people with higher linoleic acid intake also differ in diet and lifestyle. Blood levels reflect more than diet. Industry links are noted for the 2019 analysis.

Why researchers looked

Linoleic acid became a heart topic because it lowers cholesterol when it replaces saturated fat, and cohort studies found a link with lower risk.

Traditional use

Not described in the sources read.

Proposed mechanism Not established

Not established. The reviews describe associations, not a proven mechanism.

A proposed mechanism does not show that the effect happens in people.

No safety signal in these cohort results; trials below give a mixed picture.

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Heart disease events in trials that replaced saturated fat with omega-6

Mixed findings

Trials that swapped saturated fat for omega-6 fat gave mixed results. A 2018 Cochrane review found little or no difference in deaths or cardiovascular events. A 2010 review of 8 trials found fewer coronary events. Two re-analyses of old trials found no benefit, and one found more deaths.

4 studiesLinoleic acid from vegetable oils, margarines and safflower or corn o…

Studies, doses and limits

What the trials found

Cochrane 2018: 19 trials, 6,461 people, 1 to 8 years. Low-quality evidence of little or no difference in all-cause death (RR 1.00, 0.88 to 1.12) or cardiovascular events (RR 0.97, 0.81 to 1.15); very uncertain for cardiovascular death, coronary events and stroke; heart attack may fall a little (RR 0.88, 0.76 to 1.02). Mozaffarian 2010: 8 trials, 13,614 people, polyunsaturated fat in place of saturated fat lowered coronary events by 19% (RR 0.81, 0.70 to 0.95), but that included omega-3 and several trials changed other fats. Sydney Diet Heart Study (recovered data, 458 men with a recent coronary event): more deaths with safflower-oil linoleic acid (all-cause 17.6% versus 11.8%, HR 1.62, 1.00 to 2.64). Minnesota Coronary Experiment (recovered data, 9,423 people): cholesterol fell 13.8% versus 1.0% but there was no mortality benefit; five-trial meta-analysis, coronary deaths 1.13 (0.83 to 1.54), all-cause deaths 1.07 (0.90 to 1.27).

Results

Mixed. The swap lowers cholesterol, but trials do not clearly show fewer deaths or heart events, and one trial suggested more deaths. This is about replacing saturated fat, not adding omega-6 on top.

Effect sizes as reported

Cochrane: RR 1.00 for deaths, 0.97 for cardiovascular events. Sydney: HR 1.62 for deaths.

Why this rating

Mixed: Cochrane rates the evidence low to very low quality and finds little or no difference; one review of 8 trials and one trial point opposite ways.

Form and dose studied

Linoleic acid from vegetable oils, margarines and safflower or corn oil in the diet; not a supplement capsule.

Who was studied

Adults with or without heart disease; some trials were in hospital residents or men after a coronary event.

Limits

Few trials were at low risk of bias (3 of 19 in Cochrane). Diets changed more than one fat. Old trials used products that differ from today's. The Cochrane review was funded by WHO.

Why researchers looked

The old idea was that swapping saturated fat for vegetable oil lowers cholesterol and so lowers heart attacks. Researchers have tested that in randomised trials.

Traditional use

Not described in the sources read.

Proposed mechanism Human biomarker

The trials tested the cholesterol-lowering idea. The Minnesota re-analysis found cholesterol fell but deaths did not.

A proposed mechanism does not show that the effect happens in people.

The Sydney trial reported more deaths in the linoleic acid group; see the Safety tab.

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Blood cholesterol when omega-6 replaces other fats

High certainty

In trials, eating more omega-6 fat lowered total cholesterol a little. It made little or no difference to LDL, HDL or triglycerides in the Cochrane review.

2 studiesDietary omega-6 replacing other fats; trial amounts vary.

Studies, doses and limits

What the trials found

Cochrane 2018: high-quality evidence that increasing omega-6 fats lowers total serum cholesterol a little in the long term (mean difference -0.33 mmol/L, -0.50 to -0.16; 10 trials, 4,280 people; heterogeneity partly explained by dose). Little or no effect on triglycerides (-0.01 mmol/L), HDL (-0.01 mmol/L) or LDL (-0.04 mmol/L, low quality, 2 trials). The Minnesota trial showed a 13.8% fall in serum cholesterol with a corn-oil linoleic acid diet.

Results

A small fall in total cholesterol is well supported. It does not show a drop in deaths or heart attacks.

Effect sizes as reported

Total cholesterol -0.33 mmol/L (95% CI -0.50 to -0.16).

Why this rating

High for a small fall in total cholesterol (the Cochrane authors' own rating); low for LDL, HDL and triglycerides.

Form and dose studied

Dietary omega-6 replacing other fats; trial amounts vary.

Who was studied

Adults, mostly in trials lasting a year or more.

Limits

The biggest falls came where the omega-6 fat replaced saturated fat. High variation between trials (I2 81%).

Why researchers looked

Cholesterol was the reason omega-6 oils were first promoted for the heart.

Traditional use

Not described in the sources read.

Proposed mechanism Human biomarker

Replacing saturated fat lowers cholesterol; the abstracts do not detail the pathway.

A proposed mechanism does not show that the effect happens in people.

No safety signal for cholesterol itself; see the Safety tab for deaths in older trials.

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Inflammation: does more linoleic acid raise inflammatory markers?

Moderate certainty

Some online posts say omega-6 fats drive inflammation. In randomised trials in healthy adults, more linoleic acid did not significantly change inflammatory blood markers. One meta-analysis hints that a large rise in intake might raise C-reactive protein (CRP).

3 studiesLinoleic acid from food or oils in the trials; amounts varied.

Studies, doses and limits

What the trials found

Johnson and Fritsche 2012: 15 randomised studies in healthy non-infant people found no significant changes in C-reactive protein, fibrinogen, cytokines, adhesion molecules or TNF-alpha with higher linoleic acid. Su 2017: 30 randomised studies, 1,377 adults; TNF (SMD -0.01), IL-6 (SMD 0.11) and CRP (SMD 0.09, -0.05 to 0.24) showed no significant effect, though subgroup analysis suggested a larger intake increase might raise CRP. A 2025 review says the pro-inflammatory idea began as a hypothesis, led to conflicting interpretations, and that most human evidence supports beneficial associations with cardiometabolic outcomes.

Results

Randomised studies in healthy adults did not show a rise in blood inflammation markers. This is about markers, not about inflammatory disease.

Effect sizes as reported

CRP SMD 0.09 (not significant); IL-6 SMD 0.11 (not significant).

Why this rating

Moderate (our rating): two systematic reviews of randomised trials agree on no significant effect, but studies were short, healthy-person only and measured markers.

Form and dose studied

Linoleic acid from food or oils in the trials; amounts varied.

Who was studied

Healthy adults; not people with inflammatory disease.

Limits

Markers are not disease outcomes. The trials in the reviews were short. Details of trial lengths and amounts were not in the abstracts.

Why researchers looked

Arachidonic acid, which the body makes from linoleic acid, is the parent of some inflammatory signals, so people ask whether eating more omega-6 causes inflammation.

Traditional use

Not described in the sources read.

Proposed mechanism Preliminary mechanism

The body can turn linoleic acid into arachidonic acid, which is a precursor of eicosanoid signals; the review abstracts describe the concern, not a measured effect.

A proposed mechanism does not show that the effect happens in people.

Ulcerative colitis and colorectal cancer links are in the Evidence and Safety tabs.

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Type 2 diabetes risk (blood-level link)

Low certainty

In a pooled analysis of 20 studies, people with higher linoleic acid levels in their blood or fat tissue were less likely to develop type 2 diabetes. Arachidonic acid levels were not linked. This is a link, not proof.

2 studiesBlood or tissue levels, which reflect diet and body processing; no su…

Studies, doses and limits

What the trials found

Wu 2017: 39,740 adults without diabetes, 4,347 new cases over 366,073 person-years. Linoleic acid biomarkers were linked to lower diabetes risk (RR 0.65 per interquintile range, 0.60 to 0.72). Arachidonic acid biomarkers were not significantly linked (RR 0.96, 0.88 to 1.05). Results were not significantly changed by age, BMI, sex, race, aspirin use, omega-3 levels or FADS gene variants. A 2025 review also mentions beneficial human associations for glucose regulation.

Results

People with higher linoleic acid in their blood were less likely to get type 2 diabetes later. Arachidonic acid levels showed no link either way.

Effect sizes as reported

RR 0.65 for linoleic acid; RR 0.96 for arachidonic acid.

Why this rating

Low (our rating): a large, consistent observational result, but observational, and two authors received Unilever research grants for it.

Form and dose studied

Blood or tissue levels, which reflect diet and body processing; no supplement was tested.

Who was studied

Adults aged 49 to 76 on average, without diabetes at the start.

Limits

Observational. Blood levels are an imperfect marker of intake. There was high variation between cohorts (I2 54%).

Why researchers looked

Linoleic acid might affect insulin sensitivity, so researchers looked at who later developed diabetes.

Traditional use

Not described in the sources read.

Proposed mechanism Not established

Not established. The abstract describes associations.

A proposed mechanism does not show that the effect happens in people.

No safety signal in this result.

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Cancer overall (umbrella of cohort studies)

Very low certainty

A 2025 review of 150 publications linked higher omega-6 intake and blood levels to lower overall cancer, but the link ran the other way for ovarian and endometrial cancer. Results differ by cancer type, so no simple message fits.

1 studiesDietary intake and blood levels.

Studies, doses and limits

What the trials found

Sadeghi 2025 (umbrella review and meta-analysis of cohort evidence): higher dietary omega-6 and circulating levels were linked to lower cancer incidence, cardiovascular disease and all-cause death in the general population; omega-6 intake was linked to lower risks of lung and prostate cancer but higher risks of ovarian and endometrial cancer; the protective links were absent in people with pre-existing health conditions. Effect sizes and GRADE ratings were not in the abstract.

Results

Observational links point both ways depending on the cancer. They do not show that omega-6 causes or prevents any cancer.

Effect sizes as reported

Effect sizes not in the abstract.

Why this rating

Very low (our rating): observational, mixed direction, and the numbers were not read.

Form and dose studied

Dietary intake and blood levels.

Who was studied

General population; not people with existing disease.

Limits

Only the abstract was read. The review pooled many cohort meta-analyses with different designs.

Why researchers looked

Because omega-6 fats feed inflammatory signalling, researchers have asked whether they raise or lower cancer risk.

Traditional use

Not described in the sources read.

Proposed mechanism Not established

Not established.

A proposed mechanism does not show that the effect happens in people.

The higher ovarian and endometrial cancer links are a caution, not a firm finding.

¹⁶

Colorectal cancer risk (a possible harm signal)

Very low certainty

A 2025 meta-analysis of 20 cohort studies found that higher dietary linoleic acid intake was linked to somewhat higher colorectal cancer risk, but tissue levels were not. It does not show that linoleic acid causes cancer.

1 studiesDietary intake from food questionnaires.

Studies, doses and limits

What the trials found

Atashi 2025: 20 prospective cohorts, 787,490 adults. Highest versus lowest dietary linoleic acid intake: colorectal cancer RR 1.15 (1.05 to 1.27), rectal cancer RR 1.30 (1.00 to 1.68). One extra gram a day of dietary linoleic acid: colon cancer RR 1.01 (1.00 to 1.02). Total omega-6 and arachidonic acid were not linked to cancer. Tissue levels of omega-6, linoleic acid and arachidonic acid were not linked to colorectal cancer.

Results

A small increase in risk with higher dietary intake, not seen with tissue levels, in observational studies.

Effect sizes as reported

Colorectal RR 1.15 (1.05 to 1.27).

Why this rating

Very low (our rating): observational, small effect, and tissue levels did not agree with diet.

Form and dose studied

Dietary intake from food questionnaires.

Who was studied

Adults in cohort studies.

Limits

Diet questionnaires are imprecise and people who eat more omega-6 oils may eat other foods that differ. The authors report no competing interests.

Why researchers looked

Researchers checked whether linoleic acid, which feeds inflammatory signals, raises bowel cancer risk.

Traditional use

Not described in the sources read.

Proposed mechanism Not established

Not established.

A proposed mechanism does not show that the effect happens in people.

A possible harm signal; see the Safety tab.

Ulcerative colitis risk (a possible harm signal)

Very low certainty

In one European study, people with the highest linoleic acid intake were more likely to develop ulcerative colitis later. The study was small in cases and cannot show cause.

1 studiesDietary intake from food questionnaires.

Studies, doses and limits

What the trials found

EPIC nested case-control study 2009: 203,193 people followed for a median of 4 years, 126 developed ulcerative colitis. Highest versus lowest quartile of linoleic acid intake: OR 2.49 (1.23 to 5.07); trend OR 1.32 per quartile (1.04 to 1.66). The authors estimate that about 30% of cases could be linked to intakes above the lowest quartile.

Results

A link in one observational study of 126 cases.

Effect sizes as reported

OR 2.49 (1.23 to 5.07).

Why this rating

Very low (our rating): one observational study with few cases and one baseline diet questionnaire.

Form and dose studied

Dietary intake from food questionnaires.

Who was studied

Adults aged 30 to 74 in five European countries.

Limits

Only 126 cases. Diet may change before the diagnosis. The "30% of cases" estimate assumes cause.

Why researchers looked

Arachidonic acid made from linoleic acid is the source of inflammatory signals that are higher in the gut lining of people with ulcerative colitis.

Traditional use

Not described in the sources read.

Proposed mechanism Hypothesis

The authors proposed that arachidonic acid products, which are higher in ulcerative colitis, link linoleic acid intake to the disease; this was not tested.

A proposed mechanism does not show that the effect happens in people.

A possible harm signal; see the Safety tab.

⁷

Arachidonic acid supplements and muscle response to exercise

Not enough evidence

In one small set of trials, 19 trained men took an arachidonic acid supplement or a placebo for 4 weeks. It did not change muscle building after a leg session. It raised some inflammation signals right after exercise but did not worsen soreness or strength loss.

3 studiesArachidonic acid supplement versus corn-soy-oil placebo. This is diff…

Studies, doses and limits

What the trials found

Three reports from one randomised trial of 19 resistance-trained men (ARA n = 9; placebo n = 10) given 1.5 g a day of ARA or a corn-soy-oil placebo for 4 weeks. Muscle protein synthesis after exercise did not differ (P = 0.212). A marker of ribosome building rose at 48 hours only in the ARA group (P = 0.012). ARA raised plasma and muscle arachidonic acid, did not raise basal inflammation, and raised exercise-stimulated creatine kinase (P = 0.046) and white cell counts after a leg session, without more soreness or force loss.

Results

No clear muscle benefit was shown, and the effects seen were small and short-lived.

Effect sizes as reported

No difference in muscle protein synthesis (P = 0.212).

Why this rating

Insufficient: one very small trial reported three ways, short, with lab markers rather than muscle size or strength.

Form and dose studied

Arachidonic acid supplement versus corn-soy-oil placebo. This is different from linoleic acid from food.

Who was studied

Young, resistance-trained men only.

Limits

Nineteen men, four weeks. Women, older adults and people with disease were not studied. Funding was not stated in the abstracts.

Why researchers looked

Arachidonic acid is a parent of prostaglandins that might help muscle growth, and it is sold as a supplement for lifters.

Traditional use

Not described in the sources read.

Proposed mechanism Hypothesis

ARA is a precursor of prostaglandins with possible roles in muscle growth (trial authors' hypothesis).

A proposed mechanism does not show that the effect happens in people.

Transiently higher inflammation after exercise; see the Safety tab.

^{12 10 11}

Arachidonic acid in plant-based diets and infancy

Low certainty

Arachidonic acid is nearly absent from plant foods, so people ask whether vegans lack it. A 2025 expert position paper says healthy adults, pregnant and breastfeeding women can make it from linoleic acid and do not need ARA supplements. Infants need breast milk or ARA-containing formula.

1 studiesDietary arachidonic acid and conversion from linoleic acid.

Studies, doses and limits

What the trials found

Position paper of the Research Institute for Plant-based Nutrition (2025): ARA is virtually non-existent in plant foods; ARA is discussed as conditionally essential, particularly in early infancy and childhood; healthy adults and pregnant and lactating women can synthesise ARA from linoleic acid and do not need ARA supplements even on plant-based diets; infants should be breastfed or given ARA-containing formula; infants, children and teens probably make enough but data are sparse; there are no reference ranges to diagnose deficiency. The authors call their recommendations preliminary and say more studies in risk groups are urgently needed.

Results

Expert consensus on limited data: adults can make what they need, infants have special needs, and the evidence is sparse.

Effect sizes as reported

No effect size applies.

Why this rating

Low (our rating): an expert consensus paper with sparse underlying data, written by authors who declare no competing interests.

Form and dose studied

Dietary arachidonic acid and conversion from linoleic acid.

Who was studied

Vegetarians and vegans; pregnant and breastfeeding women; infants and children.

Limits

It is a position paper, not a trial. The authors say the data are sparse.

Why researchers looked

Arachidonic acid is a building block in early life, and vegetarians and vegans eat almost none.

Traditional use

Not described in the sources read.

Proposed mechanism Established physiology

The body can turn linoleic acid into arachidonic acid (position paper).

A proposed mechanism does not show that the effect happens in people.

Ask a doctor, midwife or paediatric dietitian about infants.

¹⁸

Connections to the rest of health

How Omega-6 fatty acids connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Evidence status	Context	Studies
Balanced Nutrition	High certainty	An essential fat that comes from food: Linoleic acid is an omega-6 fat the body cannot make, so it has to come from food. The NHS says most people get enough omega-6 in their diet. Vegetable oils, nuts and seeds are the main sources. By USDA data, one tablespoon of soybean oil has about 6.9 g, one tablespoon of corn oil about 7.2 g and one ounce of almonds about 3.5 g of linoleic acid.	^{21 23 5 18}
Heart Health	Low certainty	Heart disease risk: what large observational studies found: Large pooled studies of people's diets and blood levels link higher linoleic acid to lower heart disease risk. This is a link, not proof that eating more linoleic acid prevents heart disease.	^{3 9 16}
Heart Health	Mixed findings	Heart disease events in trials that replaced saturated fat with omega-6: Trials that swapped saturated fat for omega-6 fat gave mixed results. A 2018 Cochrane review found little or no difference in deaths or cardiovascular events. A 2010 review of 8 trials found fewer coronary events. Two re-analyses of old trials found no benefit, and one found more deaths.	^{6 13 14 15}
Cholesterol Balance	High certainty	Blood cholesterol when omega-6 replaces other fats: In trials, eating more omega-6 fat lowered total cholesterol a little. It made little or no difference to LDL, HDL or triglycerides in the Cochrane review.	^{6 15}
Heart Health	Moderate certainty	Inflammation: does more linoleic acid raise inflammatory markers?: Some online posts say omega-6 fats drive inflammation. In randomised trials in healthy adults, more linoleic acid did not significantly change inflammatory blood markers. One meta-analysis hints that a large rise in intake might raise C-reactive protein (CRP).	^{8 17 2}
Blood Sugar	Low certainty	Type 2 diabetes risk (blood-level link): In a pooled analysis of 20 studies, people with higher linoleic acid levels in their blood or fat tissue were less likely to develop type 2 diabetes. Arachidonic acid levels were not linked. This is a link, not proof.	^{19 2}
Preventive Wellness	Very low certainty	Cancer overall (umbrella of cohort studies): A 2025 review of 150 publications linked higher omega-6 intake and blood levels to lower overall cancer, but the link ran the other way for ovarian and endometrial cancer. Results differ by cancer type, so no simple message fits. Colorectal cancer risk (a possible harm signal): A 2025 meta-analysis of 20 cohort studies found that higher dietary linoleic acid intake was linked to somewhat higher colorectal cancer risk, but tissue levels were not. It does not show that linoleic acid causes cancer.	^{16 1}
Gut Health	Very low certainty	Ulcerative colitis risk (a possible harm signal): In one European study, people with the highest linoleic acid intake were more likely to develop ulcerative colitis later. The study was small in cases and cannot show cause.	⁷
Muscle Recovery	Not enough evidence	Arachidonic acid supplements and muscle response to exercise: In one small set of trials, 19 trained men took an arachidonic acid supplement or a placebo for 4 weeks. It did not change muscle building after a leg session. It raised some inflammation signals right after exercise but did not worsen soreness or strength loss.	^{12 10 11}
Balanced Nutrition	Low certainty	Arachidonic acid in plant-based diets and infancy: Arachidonic acid is nearly absent from plant foods, so people ask whether vegans lack it. A 2025 expert position paper says healthy adults, pregnant and breastfeeding women can make it from linoleic acid and do not need ARA supplements. Infants need breast milk or ARA-containing formula.	¹⁸

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Whole Body	Biological association	High certainty	Studied for: An essential fat that comes from food Studied for: Cancer overall (umbrella of cohort studies)	^{21 23 5 18 16}
Heart Circulation	Biological association	Low certainty	Studied for: Heart disease risk: what large observational studies found Studied for: Heart disease events in trials that replaced saturated fat with omega-6	^{3 9 16 6 13 14 15}
Cardiovascular System	Biological association	Low certainty	Studied for: Heart disease risk: what large observational studies found Studied for: Heart disease events in trials that replaced saturated fat with omega-6	^{3 9 16 6 13 14 15 8 17 2}
Immune System	Biological association	Moderate certainty	Studied for: Inflammation: does more linoleic acid raise inflammatory markers?	^{8 17 2}
Endocrine System	Biological association	Low certainty	Studied for: Type 2 diabetes risk (blood-level link)	^{19 2}
Digestive System	Biological association	Very low certainty	Studied for: Colorectal cancer risk (a possible harm signal) Studied for: Ulcerative colitis risk (a possible harm signal)	^{1 7}
Bones Joints Muscles	Biological association	Not enough evidence	Studied for: Arachidonic acid supplements and muscle response to exercise	^{12 10 11}

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Ulcerative colitis	Adverse effect or risk	Observational association	Higher intake was linked to ulcerative colitis in one European study. Higher linoleic acid intake was linked to ulcerative colitis in one European study. Preparation or compound: Dietary linoleic acid	⁷
Colorectal cancer	Adverse effect or risk	Meta analysis of cohorts	Higher dietary intake, not tissue levels, was linked to higher risk. Preparation or compound: Dietary linoleic acid	¹
High cholesterol		Meta analysis	Omega-6 lowered total cholesterol a little in a Cochrane review. Preparation or compound: Dietary omega-6	⁶
Type 2 diabetes		Observational association	Higher blood linoleic acid was linked to lower diabetes risk. Preparation or compound: Linoleic acid biomarkers	¹⁹

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Total cholesterol	Biological association	High certainty	Measured in trials: lower (small fall). A lab change is not the same as a health benefit.	^{6 15}
LDL, HDL and triglycerides	Biological association	Low certainty	Measured in trials: little or no change. A lab change is not the same as a health benefit.	⁶
Inflammation blood markers (CRP, IL-6, TNF)	Biological association	Moderate certainty	Measured in trials: no significant change. A lab change is not the same as a health benefit.	^{17 8}
Linoleic acid level in blood and fat tissue	Biological association	Low certainty	Measured in trials: higher level linked to lower risk (observational). A lab change is not the same as a health benefit.	⁹
Linoleic acid level in blood and diabetes risk	Biological association	Low certainty	Measured in trials: higher level linked to lower risk (observational). A lab change is not the same as a health benefit.	¹⁹
Arachidonic acid in plasma and muscle	Biological association	Not enough evidence	Measured in trials: higher after supplement. A lab change is not the same as a health benefit.	¹¹
Inflammation after a hard exercise session	Biological association	Not enough evidence	Measured in trials: higher response after exercise (transient). A lab change is not the same as a health benefit.	¹⁰

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
FADS1 / FADS (fatty acid desaturase) variants	Preliminary mechanism	Human	In two pooled analyses, FADS variants did not significantly change the link between omega-6 levels and diabetes; heterogeneity by FADS1 genotype was explored for cardiovascular disease with no consistent difference.	^{19 9}

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
Omega-3 fats	Preliminary mechanism	Human	The AHA says to increase long-chain omega-3 while maintaining omega-6.	⁵

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Linoleic acid (LA, 18:2 n-6)	Biological association	Human	Essential in the diet. The predominant omega-6 fat. The body can make arachidonic acid from it. Preparation or compound: Vegetable oils, nuts and seeds	^{23 21 2}
Arachidonic acid (ARA or AA, 20:4 n-6)	Biological association	Human	Made from linoleic acid by healthy adults; a precursor of prostaglandins and other eicosanoids. Preparation or compound: Almost absent from plant foods	^{18 12}
Gamma-linolenic acid (GLA) and dihomo-gamma-linolenic acid (DGLA)	Biological association	Human	Seven of the 19 trials in the Cochrane review supplemented GLA; none supplemented DGLA or arachidonic acid. Preparation or compound: Not described in the sources read	⁶

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).

Evidence at a glance: what the research found for 11 outcomes

2High certainty

1Moderate certainty

3Low certainty

3Very low certainty

1Mixed findings

1Not enough evidence

Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.

An essential fat that comes from food 4 studies High certainty Heart disease risk: what large observational studies found 3 studies Low certainty Heart disease events in trials that replaced saturated fat with omega-6 4 studies Mixed findings Blood cholesterol when omega-6 replaces other fats 2 studies High certainty Inflammation: does more linoleic acid raise inflammatory markers? 3 studies Moderate certainty Type 2 diabetes risk (blood-level link) 2 studies Low certainty Cancer overall (umbrella of cohort studies) 1 study Very low certainty Colorectal cancer risk (a possible harm signal) 1 study Very low certainty Ulcerative colitis risk (a possible harm signal) 1 study Very low certainty Arachidonic acid supplements and muscle response to exercise 3 studies Not enough evidence Arachidonic acid in plant-based diets and infancy 1 study Low certainty

The evidence

The research centre for Omega-6 fatty acids. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We read the NHS fat page, re-checked linoleic acid values in saved USDA FoodData Central data, and re-read PubMed abstracts for reviews, trials and cohort studies. Only abstracts were read for studies. The NIH Office of Dietary Supplements and EFSA pages were blocked and are marked unread.

Study library: every study we checked 23

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Atashi 2025 Dietary intake and tissue biomarkers of omega-6 fatty acids and risk of colorectal cancer in adults: a systematic review and dose-response meta-analysis of prospective cohort studies. Nutr Diabetes · PMID 40251189 · DOI	Systematic review meta analysis	787490 20 prospective cohort studies, 787,490 adults	Dietary and tissue levels of omega-6 fats (total, linoleic acid, arachidonic acid) Dietary linoleic acid (omega-6) Observed intakes Cohort follow-up · vs Lowest versus highest levels	Highest versus lowest dietary linoleic acid intake was linked to higher colorectal cancer risk (RR 1.15) and rectal cancer risk (RR 1.30, 1.00 to 1.68). Each extra gram a day of dietary linoleic acid was linked to RR 1.01 for colon cancer. Total omega-6 and arachidonic acid were not linked to cancer. Tissue levels of omega-6, linoleic acid and arachidonic acid were not linked to colorectal cancer. Colorectal cancer RR 1.15 (highest versus lowest dietary LA) (95% CI 1.05 to 1.27) Methods, limits and funding Outcomes: Colorectal, colon and rectal cancer Limitations: Observational. The link was seen for dietary intake, not tissue levels, which may point to diet-related confounding or measurement error. Funding and conflicts: The authors declare no competing interests. Registration: PROSPERO CRD42024516584 Read: abstract
Berkowitz 2025 The controversial role of linoleic acid in cardiometabolic health: from molecular pathways to human studies. Front Nutr · PMID 41613930 · DOI	Narrative review human and lab (reviewed)	Narrative review of biochemical, preclinical and human studies on linoleic acid and cardiometabolic health	Linoleic acid (LA) Dietary linoleic acid (omega-6)	The authors trace why LA became controversial (first praised for lowering cholesterol, then questioned for proposed pro-inflammatory and oxidative effects). They conclude that most human evidence supports beneficial associations between LA exposure and cardiometabolic outcomes, with differences between studies linked to diet context, genes and metabolic status. Not applicable (Not applicable) Methods, limits and funding Outcomes: Origins of the LA controversy; LA and lipids, inflammation and glucose Limitations: A narrative review: no systematic search method is given in the abstract. Funding and conflicts: The authors declare no commercial or financial conflicts. Read: abstract
Farvid 2014 Dietary linoleic acid and risk of coronary heart disease: a systematic review and meta-analysis of prospective cohort studies. Circulation · PMID 25161045 · DOI	Systematic review meta analysis	310602 13 prospective cohort studies of adults, 12,479 coronary heart disease (CHD) events	Dietary linoleic acid intake (highest versus lowest category) Dietary linoleic acid (omega-6) Observed intakes, not assigned Follow-up in cohorts · vs Lowest intake category	Highest versus lowest linoleic acid intake was linked to 15% lower risk of CHD events and 21% lower risk of CHD deaths. A 5%-of-energy increase in linoleic acid replacing saturated fat was linked to 9% lower CHD events and 13% lower CHD deaths. CHD events pooled RR 0.85; CHD deaths RR 0.79 (95% CI 0.78 to 0.92 (events); 0.71 to 0.89 (deaths)) Methods, limits and funding Outcomes: Coronary heart disease events and deaths Limitations: Observational: people who eat more linoleic acid differ in other ways, so cause cannot be shown. Intake was measured by questionnaire. Funding and conflicts: Authors declare no conflicts per the record; NIH extramural support is listed. Read: abstract
Harris 2009 Omega-6 fatty acids and risk for cardiovascular disease: a science advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention. Circulation · PMID 19171857 · DOI	Regulator statement n/a	American Heart Association science advisory on omega-6 fats and cardiovascular risk	Advisory text (not read) Dietary linoleic acid (omega-6)	Only the title and authors are in the PubMed record; it has no abstract, so the advisory text was not read. Its main message is taken from the 2010 review by Harris (p20145438), which summarises it. Not applicable (Not applicable) Methods, limits and funding Outcomes: What the American Heart Association advised on omega-6 fats Limitations: Citation only. Anything said about this advisory comes from the Harris 2010 review. Funding and conflicts: Not stated (advisory by the AHA Nutrition Subcommittee). Read: citation-only
Harris 2010 Omega-6 and omega-3 fatty acids: partners in prevention. Curr Opin Clin Nutr Metab Care · PMID 20145438 · DOI	Narrative review n/a	Narrative review of the cardiovascular role of omega-6 and omega-3 fats, summarising the American Heart Association advisories	Omega-6 fats (mainly linoleic acid) in the diet Dietary linoleic acid (omega-6)	The review says the AHA concludes that Americans should maintain, and possibly increase, their omega-6 intake, and gives an approximate linoleic acid intake of about 15 g a day (12 g for women, 17 g for men) as the healthy target. It also notes calls in the popular press to cut omega-6 because of presumed proinflammatory and prothrombotic effects. Not applicable (Not applicable) Methods, limits and funding Outcomes: What the AHA concluded about omega-6 intake Limitations: A single-author review of an advisory, not new data. Funding and conflicts: Not stated in the abstract. Read: abstract
Hooper 2018 Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev · PMID 30488422 · DOI	Systematic review meta analysis	6461 19 randomised trials in adults with or without cardiovascular disease, followed for 1 to 8 years (12 trials of linoleic acid, 7 of gamma-linolenic acid)	Higher versus lower omega-6 fat intake (usually replacing saturated or monounsaturated fat) Dietary linoleic acid (omega-6) Varied by trial 1 to 8 years · vs Lower omega-6 intake	Low-quality evidence of little or no difference in all-cause deaths (RR 1.00, 0.88 to 1.12) or cardiovascular events (RR 0.97, 0.81 to 1.15). Very uncertain for cardiovascular deaths, coronary events and stroke. Heart attack may fall a little (RR 0.88, 0.76 to 1.02, low quality). High-quality evidence that total cholesterol falls a little (mean difference -0.33 mmol/L); little or no change in LDL, HDL or triglycerides. All-cause mortality RR 1.00; CVD events RR 0.97; total cholesterol -0.33 mmol/L (95% CI 0.88 to 1.12 (deaths); 0.81 to 1.15 (events); -0.50 to -0.16 (cholesterol)) Methods, limits and funding Outcomes: All-cause mortality, cardiovascular events, blood fats Limitations: Only 3 of 19 trials were at low risk of bias. The omega-6 fat replaced other fats, so results show a swap, not an add-on. No trials of arachidonic acid. Funding and conflicts: WHO funded the review update (several authors were employed with that funding). Read: abstract
IBD in EPIC Study Investigators 2009 Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study. Gut · PMID 19628674 · DOI	Case control study	203193 203,193 men and women aged 30 to 74 from five European countries followed for ulcerative colitis; 126 cases, each matched with four controls	Dietary linoleic acid intake from food-frequency questionnaires (quartiles) Dietary linoleic acid (omega-6) Observed intakes Median follow-up 4.0 years · vs Lowest quartile of intake	The highest quartile of linoleic acid intake had higher odds of ulcerative colitis than the lowest (OR 2.49) with a trend across quartiles (OR 1.32 per quartile). The authors estimate that about 30% of cases could be attributed to intakes above the lowest quartile. OR 2.49 (highest versus lowest quartile) (95% CI 1.23 to 5.07) Methods, limits and funding Outcomes: New ulcerative colitis Limitations: Only 126 cases; one questionnaire at the start; observational. The "30% of cases" figure assumes cause, which this design cannot show. Funding and conflicts: Not stated in the abstract. Read: abstract
Johnson 2012 Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials. J Acad Nutr Diet · PMID 22889633 · DOI	Systematic review	Healthy non-infant people in 15 randomised studies (8 parallel, 7 crossover)	Higher dietary linoleic acid versus lower Dietary linoleic acid (omega-6) Varied by study Varied by study · vs Lower linoleic acid intake	None of the studies found significant changes in the wide range of inflammatory markers measured. The few significant results were urinary markers that the authors said did not indicate more inflammation. The authors conclude virtually no randomised evidence shows added linoleic acid raises inflammatory markers in healthy people. No significant effect on any blood marker (Not given in the abstract) Methods, limits and funding Outcomes: Blood markers of inflammation (C-reactive protein, fibrinogen, cytokines, adhesion molecules, TNF-alpha) Limitations: Healthy people only; markers are not disease outcomes; trial lengths not given in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract
Marklund 2019 Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality. Circulation · PMID 30971107 · DOI	Meta analysis of cohorts	68659 30 prospective studies from 13 countries, 15,198 cardiovascular events	Blood or fat-tissue levels of linoleic acid (LA) and arachidonic acid (AA) as markers of intake Dietary linoleic acid (omega-6) Measured levels, not assigned Median follow-up 2.5 to 31.9 years · vs Lowest versus highest quintiles	Higher LA levels were linked to lower risk of total CVD (HR 0.93), cardiovascular death (HR 0.78) and ischemic stroke (HR 0.88), and not significantly to coronary heart disease (HR 0.94, 0.88 to 1.00). Higher AA levels were not linked to higher risk; extreme quintiles showed lower total CVD risk (0.92). HR per interquintile range: CVD 0.93; CV death 0.78; stroke 0.88 (95% CI 0.88 to 0.99; 0.70 to 0.85; 0.79 to 0.98) Methods, limits and funding Outcomes: Total cardiovascular disease, coronary heart disease, ischemic stroke, cardiovascular death Limitations: Observational. Blood levels reflect more than diet. Cannot show that eating more LA lowers risk. Funding and conflicts: Industry-linked: two authors report research support from Unilever for this work; the senior author reports fees from several food and supplement companies (the record lists Bunge among them). Read: abstract
Markworth 2018 Arachidonic acid supplementation transiently augments the acute inflammatory response to resistance exercise in trained men. J Appl Physiol (1985) · PMID 29698111 · DOI	Randomised controlled trial	19 Same 19 trained men (ARA n = 9; placebo n = 10)	Arachidonic acid supplement versus corn-soy-oil placebo Arachidonic acid (omega-6) supplement 1.5 g a day 4 weeks before one exercise session · vs Corn-soy-oil placebo	ARA supplementation led to higher exercise-stimulated creatine kinase (P = 0.046) and higher blood white cell, neutrophil and monocyte counts, and larger rises in some inflammatory gene signals. It did not change muscle soreness, loss of muscle force or leukocytes in muscle. The authors conclude the inflammatory response to exercise was transiently increased but recovery was not impaired. Higher exercise-stimulated blood markers; no difference in soreness or force loss (iAUC P = 0.046 (creatine kinase)) Methods, limits and funding Outcomes: Blood and muscle inflammation after a leg-exercise session Limitations: Very small; one exercise session; trained young men. Funding and conflicts: Not stated in the abstract. Read: abstract
Markworth 2018 Arachidonic acid supplementation modulates blood and skeletal muscle lipid profile with no effect on basal inflammation in resistance exercise trained men. Prostaglandins Leukot Essent Fatty Acids · PMID 29413364 · DOI	Randomised controlled trial	19 Same 19 trained men (ARA n = 9; placebo n = 10)	Arachidonic acid supplement versus corn-soy-oil placebo Arachidonic acid (omega-6) supplement 1.5 g a day 4 weeks · vs Corn-soy-oil placebo	ARA supplementation raised plasma and muscle arachidonic acid. It lowered circulating platelet and monocyte numbers and some immune-cell gene signals in blood cells, raised muscle genes MyoD and myogenin, and did not raise basal systemic or muscle inflammation. The authors say it can "rapidly and safely" change the fatty acid profile in these men. Higher plasma and muscle ARA; no rise in basal inflammation (Not given in the abstract) Methods, limits and funding Outcomes: Blood and muscle fatty acid make-up; basal inflammation Limitations: Very small; short; the word "safely" is the authors' reading of 4 weeks in 19 healthy trained men, not a long-term safety finding. Funding and conflicts: Not stated in the abstract. Read: abstract
Mitchell 2018 Effect of dietary arachidonic acid supplementation on acute muscle adaptive responses to resistance exercise in trained men: a randomized controlled trial. J Appl Physiol (1985) · PMID 29389245 · DOI	Randomised controlled trial	19 19 men with at least 1 year of resistance-training experience	Arachidonic acid supplement versus corn-soy-oil placebo Arachidonic acid (omega-6) supplement 1.5 g a day 4 weeks, then a fasted leg-exercise session · vs Corn-soy-oil placebo	Muscle protein synthesis over the 4-hour recovery did not differ between groups (P = 0.212). Anabolic signalling did not differ. A marker of ribosome building (45S pre-rRNA) rose 48 hours after exercise only in the arachidonic acid group (P = 0.012). Satellite cell increase did not differ between groups. The authors say the findings do not support a link between ARA and short-term anabolism. No difference in muscle protein synthesis (P = 0.212) Methods, limits and funding Outcomes: Muscle protein synthesis and anabolic signals after a leg-exercise session Limitations: Very small trial (19 men); trained men only; short; lab markers, not strength or muscle size. Funding and conflicts: Not stated in the abstract. Read: abstract
Mozaffarian 2010 Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med · PMID 20351774 · DOI	Systematic review meta analysis	13614 8 randomised trials, 13,614 people, 1,042 coronary heart disease events	Higher polyunsaturated fat (about 14.9% of energy) in place of saturated fat (controls about 5.0%) Dietary linoleic acid (omega-6) About 14.9% of energy versus 5.0% At least 1 year · vs Higher saturated fat diets	Pooled risk of CHD events was 19% lower with more polyunsaturated fat in place of saturated fat. That is about 10% lower risk per 5% of energy. Longer trials showed greater benefit. RR 0.81 (all trials); RR 0.90 per 5% of energy (95% CI 0.70 to 0.95; 0.83 to 0.97) Methods, limits and funding Outcomes: Coronary heart disease events (heart attack or cardiac death) Limitations: Polyunsaturated fat here includes omega-3 as well as omega-6 and several trials changed other fats, so it is not an omega-6-only result. Predates the recovered-data analyses (2013 and 2016) that found no benefit. Funding and conflicts: Author declares NIH and other research grants and honoraria from several food-industry, regulatory and academic organisations. Read: abstract
Ramsden 2013 Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. BMJ · PMID 23386268 · DOI	Randomised controlled trial	458 458 men aged 30 to 59 in Sydney with a recent coronary event (1966 to 1973); recovered trial data plus an updated meta-analysis	Replacing saturated fat (animal fats, common margarines, shortenings) with linoleic acid from safflower oil and safflower oil margarine Dietary linoleic acid (omega-6) Not given in the abstract Trial years 1966 to 1973 · vs No specific dietary instruction or study foods	The linoleic acid group (221 men) had more deaths than controls (237 men): all-cause 17.6% versus 11.8%, cardiovascular 17.2% versus 11.0%, coronary 16.3% versus 10.1%. An updated meta-analysis of linoleic acid trials with these data showed non-significant trends towards more coronary (HR 1.33, 0.99 to 1.79) and cardiovascular deaths (1.27, 0.98 to 1.65). All-cause HR 1.62; cardiovascular HR 1.70; coronary HR 1.74 (95% CI 1.00 to 2.64; 1.03 to 2.80; 1.04 to 2.92) Methods, limits and funding Outcomes: All-cause, cardiovascular and coronary deaths Limitations: Single-blind, controls had no study foods, and the data were recovered decades later. The margarine used in the 1960s differs from today's products, but the abstract does not say how. One older trial cannot decide the question. Funding and conflicts: Life Insurance Medical Research Fund of Australia and New Zealand and the US NIAAA intramural programme; authors report no related financial relationships. Registration: NCT01621087 Read: abstract
Ramsden 2016 Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73). BMJ · PMID 27071971 · DOI	Randomised controlled trial	9423 9,423 women and men aged 20 to 97 in one nursing home and six state mental hospitals in Minnesota (1968 to 1973); recovered data plus a meta-analysis of five trials (n = 10,808)	Replacing saturated fat with linoleic acid from corn oil and corn oil margarine Dietary linoleic acid (omega-6) Not given in the abstract Trial years 1968 to 1973 · vs Diet high in saturated fat	The linoleic acid diet lowered serum cholesterol (-13.8% versus -1.0%) but there was no mortality benefit in the full cohort or any subgroup. Each 30 mg/dL cholesterol fall was linked to 22% higher risk of death in adjusted models (HR 1.22). No benefit for atherosclerosis or heart attacks at autopsy. In a meta-analysis of five trials there was no benefit on coronary deaths (1.13, 0.83 to 1.54) or all-cause deaths (1.07, 0.90 to 1.27). Cholesterol -13.8% versus -1.0% (P < 0.001); death HR 1.22 per 30 mg/dL fall (95% CI 1.14 to 1.32) Methods, limits and funding Outcomes: All-cause death, serum cholesterol, heart attacks and atherosclerosis at autopsy Limitations: Institutionalised people; analysis of recovered data; the cholesterol-and-death link is an association inside the trial. Funding and conflicts: US NIAAA intramural programme; authors report no related financial relationships. Read: abstract
Sadeghi 2025 Dietary and circulating omega-6 fatty acids and their impact on cardiovascular disease, cancer risk, and mortality: a global meta-analysis of 150 cohorts and meta-regression. J Transl Med · PMID 40075437 · DOI	Umbrella review	Umbrella review and updated meta-analysis of 150 publications on dietary and circulating omega-6 and cardiovascular disease, cancer and mortality in the general population	Dietary intake and circulating levels of omega-6 fats Dietary linoleic acid (omega-6) Observed levels Cohort follow-up · vs Lowest versus highest levels	Higher dietary intake and circulating omega-6 were linked to lower risk of cardiovascular disease, cancer overall and all-cause death, especially coronary heart disease and stroke. Omega-6 intake was linked to lower risks of lung and prostate cancer but higher risks of ovarian and endometrial cancer. The protective links were absent in people with existing health conditions. Not given in the abstract (Not given in the abstract) Methods, limits and funding Outcomes: Cardiovascular disease, cancer incidence, all-cause mortality Limitations: Based on observational studies. Numbers and GRADE ratings are not in the abstract, so they were not read. Funding and conflicts: The authors declare no competing interests. Registration: PROSPERO CRD42024522842 Read: abstract
Su 2017 Dietary linoleic acid intake and blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials. Food Funct · PMID 28752873 · DOI	Systematic review meta analysis	1377 30 randomised controlled studies in adults, 1,377 people	Higher dietary linoleic acid versus lower Dietary linoleic acid (omega-6) Varied by study Varied by study · vs Lower linoleic acid intake	No significant effect of higher linoleic acid intake on TNF (SMD -0.01), IL-6 (SMD 0.11), adiponectin or MCP-1. CRP (16 studies) was not significantly changed (SMD 0.09, -0.05 to 0.24), but subgroup and meta-regression analysis suggested that a larger rise in linoleic acid intake might raise CRP. CRP SMD 0.09 (not significant) (95% CI -0.05 to 0.24) Methods, limits and funding Outcomes: Blood levels of cytokines (TNF, IL-6), C-reactive protein (CRP), fibrinogen, adhesion molecules Limitations: Few studies for some markers. The CRP signal comes from subgroup analysis and is only a suggestion. Funding and conflicts: Not stated in the abstract. Read: abstract
Weder 2025 Arachidonic acid as a potentially critical nutrient for vegetarians and vegans - position paper of the Research Institute for Plant-based Nutrition (IFPE). Lipids Health Dis · PMID 40684216 · DOI	Narrative review n/a	Position paper on arachidonic acid (ARA) in vegetarian and vegan diets, with focus on pregnancy, breastfeeding, infants and children	Arachidonic acid (20:4 n-6) and its making from linoleic acid Dietary linoleic acid (omega-6)	ARA is virtually absent from plant foods. The authors conclude that healthy adults and pregnant and breastfeeding women can make ARA from linoleic acid and do not need ARA supplements, even on plant-based diets. Infants should be breastfed or given ARA-containing formula. Children and teens probably make enough, but data are sparse. There are no reference ranges to test for deficiency, and the recommendations are described as preliminary. Not applicable (Not applicable) Methods, limits and funding Outcomes: Whether plant-based eaters need ARA from food or supplements Limitations: Expert consensus on limited data; the authors say further studies in risk groups are urgently needed. Funding and conflicts: The authors declare no competing interests. Read: abstract
Wu 2017 Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39 740 adults from 20 prospective cohort studies. Lancet Diabetes Endocrinol · PMID 29032079 · DOI	Meta analysis of cohorts	39740 20 prospective cohort studies from ten countries; adults without type 2 diabetes at the start, 4,347 new cases	Blood or fat-tissue levels of linoleic acid and arachidonic acid Dietary linoleic acid (omega-6) Measured levels, not assigned 366,073 person-years · vs Lowest versus highest quintiles	Higher linoleic acid levels were linked to lower type 2 diabetes risk (RR 0.65 per interquintile range). Arachidonic acid levels were not significantly linked (RR 0.96, 0.88 to 1.05). Results were not significantly changed by age, BMI, sex, race, aspirin use, omega-3 levels or variants of the FADS gene. Linoleic acid RR 0.65; arachidonic acid RR 0.96 (95% CI 0.60 to 0.72; 0.88 to 1.05) Methods, limits and funding Outcomes: New type 2 diabetes Limitations: Observational; blood levels are an imperfect marker of intake; high heterogeneity between cohorts (I2 54% and 63%). Funding and conflicts: Industry-linked: two authors received research grants from Unilever for this study; the senior author reports fees from several companies. Read: abstract
s-efsa-dri-lipids EFSA opinion on dietary reference values for fats (including linoleic acid) · Source	Regulator page n/a			Methods, limits and funding Read: blocked
s-nhs-fats Fat: the facts (NHS; page last reviewed 14 April 2023, next review due 14 April 2026) · Source	Regulator page n/a			Methods, limits and funding Read: full-text
s-nih-ods-omega3 NIH Office of Dietary Supplements: Omega-3 Fatty Acids fact sheet for health professionals · Source	Regulator page n/a			Methods, limits and funding Read: blocked
s-usda-sr-legacy-omega6 USDA FoodData Central, SR Legacy (April 2018 release): linoleic acid 18:2 for soybean oil (FDC 171411), corn oil (171029), canola oil (172336), hemp seed (170148), almonds (170567), dry-roasted peanuts (173806) · Source	Nutrient database n/a			Methods, limits and funding Read: saved-copy

What we do not know yet

No randomised trial of linoleic acid capsules for heart disease, diabetes or inflammation was read; trials changed whole-diet fats.
Arachidonic acid supplements were tested only in 19 trained men for four weeks.
No interaction study with blood thinners or NSAIDs was read.
The NIH Office of Dietary Supplements and EFSA pages were blocked, so no official upper limit or EU reference value is stated.
Oil quality, rancidity and supplement label accuracy were not researched.
The numbers behind the cancer umbrella review were not in the abstract and were not read.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue before the page changes.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Other 7

●

Total cholesterol

Lower (small fall) in trials

The total amount of cholesterol in the blood.

High certainty

Results and what it means

Why it was measured

To see whether swapping other fats for omega-6 changes blood fats.

Statistical vs. clinical meaning

A small, consistent fall in total cholesterol.

Safety implication

Lower cholesterol did not mean fewer deaths in Minnesota.

Study	Result	People	Product
⁶	Mean difference -0.33 mmol/L (95% CI -0.50 to -0.16)	4,280 adults in 10 trials	Higher omega-6 fat intake, usually replacing saturated or monounsaturated fat
¹⁵	-13.8% versus -1.0% (P < 0.001)	9,423 residents of one nursing home and six hospitals	Corn-oil linoleic acid diet replacing saturated fat

^{6 15}

●

LDL, HDL and triglycerides

Little or no change in trials

Other blood fats: "bad" LDL, "good" HDL and triglycerides.

Low certainty

Results and what it means

Why it was measured

To see which blood fats change.

Statistical vs. clinical meaning

Little or no effect.

Safety implication

None described.

Study	Result	People	Product
⁶	LDL -0.04 mmol/L (-0.21 to 0.14); HDL -0.01 mmol/L (-0.03 to 0.02); triglycerides -0.01 mmol/L (-0.23 to 0.21)	244 (LDL), 1,995 (HDL) and 834 (triglycerides) adults	Higher omega-6 fat intake

⁶

●

Inflammation blood markers (CRP, IL-6, TNF)

No significant change in trials

Blood signals that rise with inflammation.

Moderate certainty

Results and what it means

Why it was measured

To test the claim that more omega-6 raises inflammation.

Statistical vs. clinical meaning

No clear rise; a possible CRP rise at large intake increases is only a suggestion from one analysis.

Safety implication

None described.

Study	Result	People	Product
¹⁷	CRP SMD 0.09 (-0.05 to 0.24); IL-6 SMD 0.11 (-0.07 to 0.29); TNF SMD -0.01 (-0.19 to 0.17)	30 randomised studies, 1,377 adults	Higher dietary linoleic acid
⁸	No significant findings across 15 randomised studies	Healthy non-infant people	Higher dietary linoleic acid

^{17 8}

●

Linoleic acid level in blood and fat tissue

Higher level linked to lower risk (observational) in trials

How much linoleic acid sits in blood or fat tissue, a marker of what people eat.

Low certainty

Results and what it means

Why it was measured

To relate omega-6 levels to later heart disease.

Statistical vs. clinical meaning

Observational link only.

Safety implication

None described.

Study	Result	People	Product
⁹	HR per interquintile range: CVD 0.93 (0.88 to 0.99); cardiovascular death 0.78 (0.70 to 0.85); ischemic stroke 0.88 (0.79 to 0.98); coronary disease 0.94 (0.88 to 1.00, not significant)	68,659 adults in 30 cohorts	Observed levels, not assigned

⁹

●

Linoleic acid level in blood and diabetes risk

Higher level linked to lower risk (observational) in trials

The share of linoleic acid in blood or fat tissue, linked to later diabetes.

Low certainty

Results and what it means

Why it was measured

To test whether omega-6 levels relate to type 2 diabetes.

Statistical vs. clinical meaning

Observational link only.

Safety implication

None described.

Study	Result	People	Product
¹⁹	RR 0.65 per interquintile range (0.60 to 0.72)	39,740 adults, 4,347 new cases	Observed biomarker levels

¹⁹

●

Arachidonic acid in plasma and muscle

Higher after supplement in trials

How much arachidonic acid sits in blood and muscle fat after a supplement.

Not enough evidence

Results and what it means

Why it was measured

To check whether an arachidonic acid supplement reaches the blood and muscle.

Statistical vs. clinical meaning

It shows the supplement is taken up, not that this helps health.

Safety implication

None beyond the exercise inflammation note.

Study	Result	People	Product
¹¹	ARA supplementation increased plasma ARA and muscle ARA; no effect on basal inflammation	19 trained men	ARA 1.5 g a day for 4 weeks versus placebo

¹¹

●

Inflammation after a hard exercise session

Higher response after exercise (transient) in trials

Blood white cells and creatine kinase after a leg session.

Not enough evidence

Results and what it means

Why it was measured

To check whether arachidonic acid supplements change the exercise inflammatory response.

Statistical vs. clinical meaning

Transient; recovery was not impaired.

Safety implication

Not a long-term safety finding.

Study	Result	People	Product
¹⁰	Higher exercise-stimulated creatine kinase (P = 0.046) and white cell counts; no change in soreness or force loss	19 trained men	ARA 1.5 g a day for 4 weeks versus placebo

¹⁰

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 4

In one old trial, swapping saturated fat for omega-6 oil was followed by more deaths. In the recovered Sydney Diet Heart Study, 458 men with a recent coronary event who swapped saturated fat for safflower-oil omega-6 had more deaths than controls: all-cause 17.6% versus 11.8% (HR 1.62, 1.00 to 2.64), cardiovascular 17.2% versus 11.0%. A later Cochrane review of 19 trials found little or no difference in deaths overall (RR 1.00) and rated the evidence low quality. The Minnesota trial found no benefit for deaths. Old trials cannot be repeated, and results are mixed. Randomised trials and meta analysis ^{14 6 15}
Higher dietary linoleic acid was linked to bowel problems in observational studies. A 2025 meta-analysis of 20 cohorts linked the highest dietary linoleic acid intake to higher colorectal cancer risk (RR 1.15, 1.05 to 1.27), though tissue levels showed no link. A 2009 European study linked the highest quartile of intake to ulcerative colitis (OR 2.49, 1.23 to 5.07). These are associations and cannot show cause. Cohort meta analysis and case control study ^{1 7}
Arachidonic acid supplements have only been tested in 19 men for 4 weeks. In a small trial in trained men, arachidonic acid (1.5 g a day for 4 weeks) raised some inflammation signals after a hard exercise session (creatine kinase P = 0.046; higher white cell counts) without more soreness or strength loss, and did not raise basal inflammation. No long-term safety data, and no data in women, older adults or people with disease, were found. Small randomised trial ^{10 11}
Infants have special needs; ask before using any supplement. A 2025 position paper says infants should be breastfed or given arachidonic acid-containing formula, and that healthy adults, pregnant and breastfeeding women can make arachidonic acid from linoleic acid without supplements. Ask a doctor, midwife or paediatrician before giving any omega-6 supplement to a child. Expert consensus ¹⁸

Side effects 7

Effect	How often	Severity and recovery	Evidence
More deaths in the safflower-oil group of the Sydney Diet Heart Study Men aged 30 to 59 with a recent coronary event; omega-6 replaced saturated fat. An updated meta-analysis showed only non-significant trends towards more coronary (HR 1.33) and cardiovascular deaths (HR 1.27).	All-cause 17.6% versus 11.8% (HR 1.62, 1.00 to 2.64, P = 0.05); cardiovascular 17.2% versus 11.0% (HR 1.70, 1.03 to 2.80).	Serious (death) Not applicable.	Randomised trial (recovered data) ¹⁴
No mortality benefit despite lower cholesterol (Minnesota Coronary Experiment) The authors say findings do not support that lowering cholesterol this way reduces coronary or all-cause death.	Cholesterol -13.8% versus -1.0%; each 30 mg/dL fall linked to HR 1.22 (1.14 to 1.32) for death in adjusted models.	Not a side effect, but a missing benefit Not applicable.	Randomised trial (recovered data) ¹⁵
Stroke result very uncertain The wide range includes both benefit and harm; no firm conclusion.	Cochrane: RR 1.36 (0.45 to 4.11), 54 events, 4 trials; very low quality.	Unknown Not stated.	Meta analysis of trials ⁶
Colorectal and rectal cancer (association) Tissue levels were not linked. Observational.	Colorectal RR 1.15 (1.05 to 1.27); rectal RR 1.30 (1.00 to 1.68) for highest versus lowest dietary linoleic acid intake.	Serious if real Not stated.	Meta analysis of cohorts ¹
Ulcerative colitis (association) Observational and small in cases.	OR 2.49 (1.23 to 5.07) for the highest versus lowest quartile; 126 cases.	Chronic condition Not stated.	Nested case control study ⁷
Higher inflammation signals after hard exercise with arachidonic acid supplements Nineteen trained men; four weeks of 1.5 g a day.	Creatine kinase iAUC P = 0.046; white cell counts higher (P < 0.001 for total white cells). No change in soreness or force loss.	Transient Described as transient by the authors.	Small randomised trial ¹⁰
Side effects of omega-6 oils in normal food use Gamma-linolenic acid oils (evening primrose, borage) are a different product with their own cautions.	No source read gave a side-effect list for linoleic acid from food.	Not established Not stated.	Gap

Liver

No source read described liver injury from linoleic acid or arachidonic acid. The liver-safety database LiverTox was not opened for this page.

How often. No frequency was found.

Monitoring. No agency monitoring advice was found.

This is a safety connection. It is not evidence that Omega-6 fatty acids supports liver health.

Medicines and supplements 4

With	Why it matters	Importance	Evidence	What to do
Saturated fat in the diet (what the omega-6 replaces) food	In trials the omega-6 fat usually replaced saturated or monounsaturated fat, so results describe a swap.	Cochrane: omega-6 fats usually displaced dietary saturated or monounsaturated fats; Farvid 2014: a 5%-of-energy increase of linoleic acid replacing saturated fat was linked to 9% lower coronary events.	Meta-analysis Moderate certainty ^{6 3}	Talk to a dietitian before changing the fats in your diet.
Omega-3 fats (EPA and DHA) supplement	Both are essential fat families; the AHA, as summarised in a 2010 review, says Americans need to increase long-chain omega-3 and maintain omega-6.	Advisory statement, not a drug interaction.	Advisory Moderate certainty ^{5 4}	See the omega-3 and the omega-6 to omega-3 ratio pages; ask a clinician about your own balance.
Blood thinners and anti-inflammatory medicines medicine	Arachidonic acid is a precursor of clotting and inflammation signals, so a link is possible in theory.	No source read tested arachidonic acid or linoleic acid supplements with blood thinners or NSAIDs.	Theory, not tested in a source read Not enough evidence ¹²	Ask a pharmacist or doctor before using an arachidonic acid supplement if you take these medicines.
Gamma-linolenic acid (GLA) oils such as evening primrose and borage supplement	GLA is also an omega-6 fat; seven of the 19 trials in the Cochrane review used GLA.	GLA oils have their own page and cautions.	Meta-analysis Moderate certainty ⁶	See the evening primrose, borage and GLA oils page.

Who should check first 7

Situation	Advice	Evidence
Pregnancy	A 2025 position paper says healthy adults and pregnant and breastfeeding women can make arachidonic acid from linoleic acid and do not need arachidonic acid supplements. No safety trial of linoleic acid or arachidonic acid supplements in pregnancy was read. Ask a doctor or midwife.	Expert consensus ¹⁸
Breastfeeding and infants	The same paper says infants should be breastfed or given arachidonic acid-containing formula. The LactMed database was not opened. Ask a doctor, midwife or paediatrician.	Expert consensus ¹⁸
Children and teenagers	The paper says infants, children and adolescents probably make enough arachidonic acid, but data are sparse. No safety trial in children was read.	Expert consensus ¹⁸
Ulcerative colitis or other bowel disease	One European study linked higher linoleic acid intake to ulcerative colitis. If you have bowel disease, ask your doctor or dietitian about fats in your diet.	Observational study ⁷
Heart disease or recent heart attack	The Sydney trial in men after a coronary event had more deaths with an omega-6 oil swap; Cochrane found little or no difference overall. Do not change heart medicines or diets without your doctor.	Randomised trial and meta analysis ^{14 6}
Allergy to nuts, seeds or soy	Many omega-6 sources are nut, seed or soy oils or foods. No source read described allergy risks for omega-6 products. If you have an allergy, ask your doctor and read labels.	Gap
Kidney disease or long-term conditions	No omega-6-specific kidney or liver advice was read. Ask your doctor before using supplements.	Gap

Overdose, product quality and regulators

Summary. No source read described poisoning from the omega-6 fats found in food. The signals are from trials and cohorts, not poisoning cases.

Animal. Not reviewed.

High dose or long term signals. Sydney trial: more deaths in the omega-6 group. Cohorts: higher colorectal cancer and ulcerative colitis with the highest intakes. No long-term data on arachidonic acid supplements.

Overdose response. No source read described an overdose of linoleic acid or arachidonic acid. If someone has swallowed a large amount of a supplement and feels unwell, call poison control or emergency services.

Genotoxicity. Not researched.

Oil quality (rancidity, heating, label accuracy) and contamination of omega-6 or arachidonic acid supplements were not researched for this page.

Oxidised or heated oils. A 2025 review says the idea that linoleic acid has pro-inflammatory and oxidative effects began as a hypothesis. No source read tested heated or rancid oils in people. ²

Supplement label accuracy. No source read examined arachidonic acid or linoleic acid product testing.

Body	Action	Date
NHS (UK) (United Kingdom)	Fat: the facts page: omega-6 fats are found in vegetable oils (rapeseed, corn, sunflower) and nuts such as walnuts, almonds and cashews; some omega-3 and omega-6 fats cannot be made by the body so small amounts are essential; most people get enough omega-6 in their diet. source	2023-04-14
American Heart Association (as summarised in a 2010 review) (United States)	AHA Nutrition Subcommittee science advisory (2009): Americans should maintain, and possibly increase, omega-6 intake. The review gives approximately 15 g a day of linoleic acid (12 g for women, 17 g for men) as the healthy target intake, and about 500 mg a day of long-chain omega-3. This is the advisory's statement, not advice to take any amount. source	2009-02-17

When to get medical help

Hives, swelling of the lips or face, wheezing or trouble breathing after eating a nut, seed or oil (possible allergy): get emergency help.
Sudden chest pain, trouble breathing or weakness on one side: call emergency services.
Blood in the stool, ongoing diarrhoea or unexplained weight loss: see a doctor.

Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

What are omega-6 fatty acids?

They are essential polyunsaturated fats. Linoleic acid is the main one in food, and the body can make arachidonic acid from it. The NHS says most people get enough omega-6.

^{21 18}

Which foods have omega-6?

The NHS names rapeseed, corn and sunflower oils and walnuts, almonds and cashews. By USDA data, a tablespoon of soybean oil has about 6.9 g of linoleic acid and an ounce of almonds about 3.5 g.

^{21 23}

Is omega-6 inflammatory?

Arachidonic acid, made from linoleic acid, is the parent of some inflammatory signals. But two reviews of randomised trials in adults found no significant rise in inflammation blood markers with more linoleic acid.

^{8 17 2}

Is omega-6 bad for the heart?

Cohort studies link higher linoleic acid to less heart disease. Trials gave mixed results: Cochrane found little or no difference in deaths or events, and one old Sydney trial found more deaths. It does not clearly harm or protect.

^{3 6 14}

Does omega-6 lower cholesterol?

A little. In 10 trials, total cholesterol fell about 0.33 mmol/L. LDL, HDL and triglycerides changed little or not at all. The Minnesota trial lowered cholesterol but not deaths.

^{6 15}

Does omega-6 raise the risk of cancer or bowel disease?

Observational studies are mixed. The highest dietary linoleic acid intakes were linked to colorectal cancer (RR 1.15) and ulcerative colitis, but tissue levels were not linked to colorectal cancer, and these studies cannot show cause.

^{1 7 16}

Does omega-6 affect diabetes?

In 20 cohorts, higher linoleic acid in the blood was linked to a lower chance of developing type 2 diabetes (RR 0.65). Arachidonic acid showed no link. This is observational.

¹⁹

Do vegans lack arachidonic acid?

A 2025 position paper says healthy adults, and pregnant and breastfeeding women, can make arachidonic acid from linoleic acid and do not need supplements. Infants should be breastfed or given formula that contains it.

¹⁸

Do arachidonic acid supplements build muscle?

One small trial in 19 trained men found no change in muscle protein synthesis after exercise. It raised some inflammation signals briefly without worse soreness. The evidence is insufficient.

^{12 10}

Is omega-6 safe in pregnancy?

No safety trial of omega-6 supplements in pregnancy was read. The 2025 position paper says pregnant women can make arachidonic acid from linoleic acid. Ask a doctor or midwife.

¹⁸

How does omega-6 relate to omega-3?

They are two essential fat families. The AHA, as summarised in a 2010 review, says to increase long-chain omega-3 while maintaining omega-6.

⁵

Can omega-6 interact with medicines?

No source read tested omega-6 supplements with blood thinners or NSAIDs, so this is unknown. Ask a pharmacist, especially before using an arachidonic acid supplement.

¹²

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-26
Last substantive update: 2026-10-26
How we research: We read the NHS fat page, re-checked linoleic acid values in saved USDA FoodData Central data, and re-read PubMed abstracts for reviews, trials and cohort studies. Only abstracts were read for studies. The NIH Office of Dietary Supplements and EFSA pages were blocked and are marked unread.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. Two pooled analyses (2017 and 2019) have authors with research grants from a food company; this is flagged in the studies table.

Sources 23

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

Atashi N, Eshaghian N, Anjom-Shoae J, Askari G, Asadi M, Sadeghi O. Dietary intake and tissue biomarkers of omega-6 fatty acids and risk of colorectal cancer in adults: a systematic review and dose-response meta-analysis of prospective cohort studies.. Nutr Diabetes. 2025. PMID 40251189. DOI 10.1038/s41387-025-00367-w. (abstract)
Berkowitz L, Araneda P, Cofré G, Sara D, Olsen M, Urzúa I et al.. The controversial role of linoleic acid in cardiometabolic health: from molecular pathways to human studies.. Front Nutr. 2025. PMID 41613930. DOI 10.3389/fnut.2025.1728865. (abstract)
Farvid MS, Ding M, Pan A, Sun Q, Chiuve SE, Steffen LM et al.. Dietary linoleic acid and risk of coronary heart disease: a systematic review and meta-analysis of prospective cohort studies.. Circulation. 2014. PMID 25161045. DOI 10.1161/CIRCULATIONAHA.114.010236. (abstract)
Harris WS, Mozaffarian D, Rimm E, Kris-Etherton P, Rudel LL, Appel LJ et al.. Omega-6 fatty acids and risk for cardiovascular disease: a science advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention.. Circulation. 2009. PMID 19171857. DOI 10.1161/CIRCULATIONAHA.108.191627. (citation-only)
Harris W. Omega-6 and omega-3 fatty acids: partners in prevention.. Curr Opin Clin Nutr Metab Care. 2010. PMID 20145438. DOI 10.1097/MCO.0b013e3283357242. (abstract)
Hooper L, Al-Khudairy L, Abdelhamid AS, Rees K, Brainard JS, Brown TJ et al.. Omega-6 fats for the primary and secondary prevention of cardiovascular disease.. Cochrane Database Syst Rev. 2018. PMID 30488422. DOI 10.1002/14651858.CD011094.pub4. (abstract)
IBD in EPIC Study Investigators, Tjonneland A, Overvad K, Bergmann MM, Nagel G, Linseisen J et al.. Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study.. Gut. 2009. PMID 19628674. DOI 10.1136/gut.2008.169078. (abstract)
Johnson GH, Fritsche K. Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials.. J Acad Nutr Diet. 2012. PMID 22889633. DOI 10.1016/j.jand.2012.03.029. (abstract)
Marklund M, Wu JHY, Imamura F, Del Gobbo LC, Fretts A, de Goede J et al.. Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality.. Circulation. 2019. PMID 30971107. DOI 10.1161/CIRCULATIONAHA.118.038908. (abstract)
Markworth JF, D'Souza RF, Aasen KMM, Mitchell SM, Durainayagam BR, Sinclair AJ et al.. Arachidonic acid supplementation transiently augments the acute inflammatory response to resistance exercise in trained men.. J Appl Physiol (1985). 2018. PMID 29698111. DOI 10.1152/japplphysiol.00169.2018. (abstract)
Markworth JF, Mitchell CJ, D'Souza RF, Aasen KMM, Durainayagam BR, Mitchell SM et al.. Arachidonic acid supplementation modulates blood and skeletal muscle lipid profile with no effect on basal inflammation in resistance exercise trained men.. Prostaglandins Leukot Essent Fatty Acids. 2018. PMID 29413364. DOI 10.1016/j.plefa.2017.12.003. (abstract)
Mitchell CJ, D'Souza RF, Figueiredo VC, Chan A, Aasen K, Durainayagam B et al.. Effect of dietary arachidonic acid supplementation on acute muscle adaptive responses to resistance exercise in trained men: a randomized controlled trial.. J Appl Physiol (1985). 2018. PMID 29389245. DOI 10.1152/japplphysiol.01100.2017. (abstract)
Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials.. PLoS Med. 2010. PMID 20351774. DOI 10.1371/journal.pmed.1000252. (abstract)
Ramsden CE, Zamora D, Leelarthaepin B, Majchrzak-Hong SF, Faurot KR, Suchindran CM et al.. Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis.. BMJ. 2013. PMID 23386268. DOI 10.1136/bmj.e8707. (abstract)
Ramsden CE, Zamora D, Majchrzak-Hong S, Faurot KR, Broste SK, Frantz RP et al.. Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73).. BMJ. 2016. PMID 27071971. DOI 10.1136/bmj.i1246. (abstract)
Sadeghi R, Norouzzadeh M, HasanRashedi M, Jamshidi S, Ahmadirad H, Alemrajabi M et al.. Dietary and circulating omega-6 fatty acids and their impact on cardiovascular disease, cancer risk, and mortality: a global meta-analysis of 150 cohorts and meta-regression.. J Transl Med. 2025. PMID 40075437. DOI 10.1186/s12967-025-06336-2. (abstract)
Su H, Liu R, Chang M, Huang J, Wang X. Dietary linoleic acid intake and blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials.. Food Funct. 2017. PMID 28752873. DOI 10.1039/c7fo00433h. (abstract)
Weder S, Müller S, Dawczynski C, Keller M. Arachidonic acid as a potentially critical nutrient for vegetarians and vegans - position paper of the Research Institute for Plant-based Nutrition (IFPE).. Lipids Health Dis. 2025. PMID 40684216. DOI 10.1186/s12944-025-02645-z. (abstract)
Wu JHY, Marklund M, Imamura F, Tintle N, Ardisson Korat AV, de Goede J et al.. Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39 740 adults from 20 prospective cohort studies.. Lancet Diabetes Endocrinol. 2017. PMID 29032079. DOI 10.1016/S2213-8587(17)30307-8. (abstract)
. EFSA opinion on dietary reference values for fats (including linoleic acid). . . (blocked)
. Fat: the facts (NHS; page last reviewed 14 April 2023, next review due 14 April 2026). . . (full-text)
. NIH Office of Dietary Supplements: Omega-3 Fatty Acids fact sheet for health professionals. . . (blocked)
. USDA FoodData Central, SR Legacy (April 2018 release): linoleic acid 18:2 for soybean oil (FDC 171411), corn oil (171029), canola oil (172336), hemp seed (170148), almonds (170567), dry-roasted peanuts (173806). . . (saved-copy)

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