Omega-6 Fatty Acids: Linoleic Acid, Arachidonic Acid and What Research Shows
What omega-6 fats are, where linoleic and arachidonic acid come from, and what cohort studies, trials and the American Heart Association advisory say about heart health and inflammation.
Content last updated . This page has not been medically reviewed.
What is Omega-6 fatty acids good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Essential fat the body cannot make
Established roleLinoleic acid is an omega-6 fat the body cannot make, so it has to come from food. Most people get enough from vegetable oils, nuts and seeds.
Supplements: Food intake covers the need for most people; there is no evidence that extra linoleic acid from supplements adds benefit when intake is adequate.
Building block of cell and mitochondrial membranes
Established roleLinoleic acid is a major fatty acid in cardiolipins, fats that help keep the energy-making parts of cells (mitochondria) intact.
Supplements: This is a normal biological role; it does not show that supplements improve cell function.
Skin health in a deficiency state
Deficiency linkEarly studies found that infants fed very low-fat diets developed skin changes that cleared when linoleic acid was added back.
Supplements: Applies to true deficiency, which is rare; no evidence from the sources we read that extra linoleic acid improves healthy skin.
Precursor of arachidonic acid and signalling molecules
Established roleThe body can turn linoleic acid into arachidonic acid, which is used to make short-lived signalling molecules (eicosanoids) involved in inflammation and clotting.
Supplements: A normal pathway, not a supplement benefit. A review reports that arachidonic acid production levels off above about 2 percent of calories from linoleic acid.
Blood cholesterol when replacing saturated fat
Preliminary or mixedIn trials, eating more omega-6 fats modestly lowered total cholesterol, with little or no effect on LDL, HDL or triglycerides in the Cochrane review. A separate review says linoleic-acid-rich diets tend to lower LDL compared with saturated or trans fat diets.
Supplements: Results come from diet changes, not from taking omega-6 supplements; findings differ between reviews.
Heart disease risk (observational link)
Preliminary or mixedLarge pooled studies of people's diets and blood levels link higher linoleic acid to lower heart disease risk. Trials of eating more omega-6 found little or no difference in deaths or cardiovascular events.
Supplements: Mixed: observational benefit, no clear trial benefit. Not a reason to take omega-6 supplements.
Inflammation balance
Lab or animal research onlyOmega-6 fats are sometimes blamed for driving inflammation. A review reports that higher linoleic acid intake has not been shown to raise inflammatory markers in humans, though some oxidised linoleic acid products may promote inflammation under oxidative stress.
Supplements: The debate is unresolved; the sources do not show that adding or cutting omega-6 changes inflammation-related health outcomes.
Type 2 diabetes and blood sugar (association)
Not enough evidenceA review reports that cohort studies link higher linoleic acid intake and blood levels with lower type 2 diabetes risk. Some data in people with obesity point the other way.
Supplements: Insufficient: reported by one review; we did not read the underlying studies.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Health goals (2)
- Heart HealthPreliminary or mixed
Observational studies link higher linoleic acid to lower heart disease risk, but trials of eating more omega-6 show little or no difference in events. Not a reason to take omega-6 supplements.
- Cholesterol BalancePreliminary or mixed
Replacing saturated fat with omega-6 modestly lowers total cholesterol in trials; effects on LDL, HDL and triglycerides were small or absent in the Cochrane review.
Body systems (3)
- Cardiovascular SystemPreliminary or mixed
Higher linoleic acid is linked to lower heart disease risk in observational studies, but trials of eating more omega-6 found little or no difference in deaths or events.
- Heart & CirculationPreliminary or mixed
Observational studies link higher linoleic acid to lower heart and stroke risk; trial evidence is low quality and mixed.
- Integumentary SystemDeficiency link
Skin changes were the early sign of linoleic acid deficiency in infants on very low-fat diets and cleared when it was restored. Deficiency is rare.
Body parts (3)
- CellsEstablished role
Linoleic acid is a component of cell and mitochondrial membrane fats and cannot be made by the body.
- HeartPreliminary or mixed
Higher linoleic acid intake and blood levels are linked to lower heart disease risk in cohorts; trials are mixed and low quality.
- SkinDeficiency link
Skin changes are the historical sign of linoleic acid deficiency; no sourced evidence of benefit for healthy skin.
Root causes (1)
- Nutrient DeficiencyDeficiency link
Not getting enough linoleic acid causes essential fatty acid deficiency (skin changes in infants; lab-confirmed deficiency in patients on certain intravenous feeds). It is rare in people eating normally.
Habits (1)
- Balanced NutritionEstablished role
Omega-6 comes from everyday foods such as vegetable oils, nuts and seeds, and the NHS says most people get enough.
Conditions & symptoms (2)
- Coronary Heart DiseasePreliminary or mixed
Higher linoleic acid intake was linked to about 15 percent lower coronary heart disease events in a pooled cohort analysis; trials of eating more omega-6 show little or no difference in events, and one older trial found higher deaths.
- Fatty Acid DeficiencyDeficiency link
Too little linoleic acid causes essential fatty acid deficiency, which is rare. It caused skin changes in infants on very low-fat diets and has been confirmed by lab markers in patients on lipid emulsions low in essential fats.
What the terms mean
- Linoleic acid (LA, 18:2 omega-6): the shortest omega-6 fat and the one regarded as essential. [2][3]
- Arachidonic acid (ARA): a longer omega-6 fat the body makes from LA. A 2025 position paper says ARA is virtually non-existent in plant foods and that healthy adults can make it from LA. [4] EFSA wrote that no intake recommendations have been specifically set for ARA in adults. [3]
- Where they are found: the NHS lists omega-6 in vegetable oils such as rapeseed, corn and sunflower, and in nuts such as walnuts, almonds and cashews. [1]
Why omega-6 became controversial
A 2010 review notes there have been calls in the popular press to reduce omega-6 intake because of presumed proinflammatory and prothrombotic effects. [5] The biochemical reason is that many eicosanoids made from arachidonic acid have pro-inflammatory and pro-thrombotic properties, while certain other omega-6 products, such as those from dihomo-gamma-linolenic acid, are anti-inflammatory. [2] The key question is whether eating more LA actually raises arachidonic acid and inflammation in people.What the research found
| Question | What the source found | Strength of evidence |
|---|---|---|
| Does more dietary LA raise inflammatory markers? | A 2026 review reports that intakes above 2 percent of calories do not significantly increase arachidonic acid levels, and that higher LA intake in humans does not increase inflammatory markers. [2] | Reported by a review; not independently read at trial level |
| Does LA intake relate to heart disease in cohorts? | A 2014 pooled analysis of 13 cohort studies (310,602 people) found the highest versus lowest LA intake associated with a 15 percent lower risk of coronary heart disease events. [6] | Observational association, evidence in adequately nourished people |
| Do blood and tissue LA levels relate to heart disease? | A 2019 analysis of 30 prospective studies found higher LA levels significantly associated with lower risks of total cardiovascular disease, cardiovascular mortality and ischemic stroke. [7] | Observational association |
| Do trials of more omega-6 prevent heart disease? | A 2018 Cochrane review (19 trials, 6,461 people, 1 to 8 years; omega-6 usually replaced saturated or monounsaturated fat) found low-quality evidence of little or no difference to all-cause mortality or cardiovascular events, and was uncertain about other outcomes. [8] | Low to very low quality; mixed |
| What did the American Heart Association advise? | A 2010 review of the AHA science advisory says Americans should maintain, and possibly increase, omega-6 intake. [5] We could not read the 2009 advisory itself. | Expert advisory |
Cohort studies cannot prove cause, and people who eat more LA also differ in other ways. Trials are fewer, shorter and often mixed with other changes. Together the evidence is mixed on benefit and does not support the claim that ordinary dietary LA causes harm.
Amounts
EFSA proposed, in 2009, a label reference value of 10 g a day of LA for adults in the EU, and noted that average adult LA intakes in some European countries range from nearly 7 to about 19 g a day. [3] That label value is not a personal target. We could not read the US National Institutes of Health fact sheet (access error), so no US Adequate Intake figure is quoted.Omega-6 and omega-3 together
The AHA review concludes that Americans need to increase long-chain omega-3 while maintaining omega-6. [5] For the ratio debate see the omega-6 to omega-3 ratio and for oils see seed oils and omega-6 claims checked.Omega-6 supplements
Evening primrose, borage and similar oils contain the omega-6 fat GLA. They are different products with their own cautions. Proper evidence not found here for LA supplements as a treatment; the Cochrane review's GLA trials were separate. [8] See ALA, EPA and DHA for omega-3 types.Frequently asked questions
Is omega-6 inflammatory?
Some molecules made from arachidonic acid are pro-inflammatory. [2] A 2026 review says higher LA intake in humans does not increase inflammatory markers. [2]
Should I cut omega-6?
The AHA advisory, as described in a 2010 review, recommends maintaining omega-6 intake. [5] A clinician or dietitian can advise on your diet.
Is arachidonic acid essential?
EFSA says strictly speaking only LA is essential, and that no intake recommendations have been specifically set for ARA in adults. [3]
Do vegans lack arachidonic acid?
A 2025 position paper says healthy adults and pregnant and lactating women can make ARA from LA and do not require ARA supplements. [4] Infants are discussed separately; ask a clinician.
Do omega-6 trials show heart benefit?
A Cochrane review found low-quality evidence of little or no difference in all-cause mortality or cardiovascular events. [8]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and who should ask a clinician
References
- NHS, Fat: the facts. Read 2026-10-22.
- Berkowitz L et al. The controversial role of linoleic acid in cardiometabolic health: from molecular pathways to human studies. Front Nutr 2026. Read 2026-10-22.
- EFSA NDA Panel, Labelling reference intake values for n-3 and n-6 polyunsaturated fatty acids, EFSA Journal 2009;1176 (copy of the opinion hosted by the EFSA Focal Point Bulgaria; efsa.europa.eu returned an access error). Read 2026-10-22.
- 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. PubMed. Read 2026-10-22.
- Harris WS. Omega-6 and omega-3 fatty acids: partners in prevention. Curr Opin Clin Nutr Metab Care 2010 (reviews the American Heart Association science advisory on omega-6). Read 2026-10-22.
- Farvid MS et al. Dietary linoleic acid and risk of coronary heart disease: a systematic review and meta-analysis of prospective cohort studies. Circulation 2014. Read 2026-10-22.
- Marklund M et al. Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality. Circulation 2019. Read 2026-10-22.
- Hooper L et al. Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2018. Read 2026-10-22.