Oils & Fats · Cooking oil
Corn Oil
Zea mays (corn oil) · also called Maize oil, corn germ oil
Corn oil is a light cooking and salad oil made from corn. It is mostly polyunsaturated fat, with some vitamin E. In feeding trials it lowered LDL cholesterol more than olive oil and coconut oil did, but the trials were short and used large amounts. A large old trial found a corn-oil diet lowered cholesterol without lowering deaths. The main cautions are calories and, for people with a corn allergy, asking an allergist.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Corn Oil
Corn oil is a polyunsaturated cooking oil made from corn. It is a food, not a proven remedy: the best evidence is a short-term fall in LDL cholesterol when it replaces other fats in large amounts, and whether that means fewer heart events or deaths is mixed.
What it is
Corn oil is the oil from corn, Zea mays, a member of the grass family (Poaceae). It is a light liquid oil used for frying, baking and dressings. The USDA item described here is an industrial and retail all-purpose salad or cooking oil.
USDA data per 100 g: 900 kcal, 100 g fat (12.9 g saturated, 27.6 g monounsaturated, 54.7 g polyunsaturated, of which 53.2 g is linoleic acid), 14.3 mg vitamin E and 1.9 mcg vitamin K. One tablespoon (13.6 g) has about 122 kcal, 1.8 g saturated fat and 1.9 mg vitamin E. There is no protein, carbohydrate or fibre. These numbers come from our stored summary of the USDA record and were not re-opened on the USDA site when this page was built.
This page covers the oil as a food. It does not cover corn as a grain, corn masa or corn-oil margarine.
What the research shows
Cholesterol is the best-studied use. In a 21-day trial in 54 adults with raised LDL, foods made with 4 tablespoons a day of corn oil lowered LDL by 10.9%, against 3.5% for extra virgin olive oil. Total and non-HDL cholesterol also fell more, and triglycerides rose less. A second report of the same trial found corn oil also lowered apolipoprotein B and LDL particle number more, while apolipoprotein A1 rose more with olive oil. A small preliminary trial (25 adults, 4 weeks) found corn oil looked better than coconut oil, but its main LDL result did not reach statistical significance. These were short trials with large amounts of oil, and the abstracts do not say who paid.
For heart disease itself the picture is mixed. A 2010 analysis of 8 trials found 19% fewer coronary events when polyunsaturated fat replaced saturated fat, and the American Heart Association advisory describes about 30% fewer cardiovascular events in such trials. But those results are about the swap in general. In the Minnesota Coronary Experiment (1968-73, 9,423 people in institutions), a diet using corn oil and corn-oil margarine lowered cholesterol and, in recovered data, did not lower deaths. A Cochrane review of 19 omega-6 trials found low-quality evidence of little or no difference in deaths or cardiovascular events.
The FDA allows only a very cautious corn oil label claim. Its 2007 letter rated the evidence as giving a very low level of comfort and says there is little scientific evidence for the claim. Pooled trials found no significant effect of linoleic acid, the main fat in corn oil, on inflammation markers overall.
Food versus supplements
The human trials are of corn oil eaten as a food fat, usually baked into muffins, rolls and yogurt, in amounts much larger than a typical serving. The pooled analyses cover polyunsaturated fat or linoleic acid from many sources. They do not cover corn kernels, corn masa or supplements.
At a glance
Traditional uses history, not proof
- Used as an everyday cooking, frying and salad oil
- Long use as a food is not proof that it treats any condition
Studied for research
- Fat and nutrient content, high certainty for the numbers (USDA)
- LDL cholesterol compared with olive oil, low certainty (one short trial, large amounts)
- LDL cholesterol compared with coconut oil, very low certainty (25 people)
- Heart events when polyunsaturated oil replaces saturated fat, moderate certainty for the swap
- FDA cautious heart claim, low certainty (FDA's own rating: very low comfort)
- Deaths, mixed (the Minnesota trial did not show fewer deaths)
- Omega-6 fat and heart events, low certainty (little or no difference)
- Inflammation markers, low certainty (no clear effect)
Main compounds
- Linoleic acid (omega-6)
- Monounsaturated fat
- Saturated fat
- Vitamin E (alpha-tocopherol)
Common forms
- Refined corn oil as a food fat (USDA values read)
- Corn-oil margarine is a different product; unrefined corn oil was not read
Research links: 2015 trial: corn oil vs olive oil on cholesterol (54 adults) · 2016 re-analysis: Minnesota Coronary Experiment · 2018 review: omega-6 fats and heart disease (Cochrane) · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Zea mays L. (corn or maize), the plant the oil comes from
- Naming authority
- L.
- Common names
- Corn oil (en); Maize oil (en); Corn germ oil (en)
- Family or group
- Poaceae (the grass family), per GBIF.
- Classification
- Plantae > Poaceae > Zea > Zea mays
- Native range
- Not verified from a source read.
- Habitat
- Not verified from a source read.
- What it looks like
- Fruit: The oil is pressed or extracted from corn. Which part of the kernel it comes from was not confirmed from a source read.
- Cultivation
- Not verified from a source read.
- Harvest and processing
- Not verified from a source read. The USDA item described here is an industrial and retail all-purpose salad or cooking oil. Pressing, refining and solvent extraction were not read.
- Look-alikes and adulterants
- Name: Corn-oil margarine; Note: A different product from the oil. Corn oil and corn-oil polyunsaturated margarine were used together in the Minnesota Coronary Experiment.; Name: Corn (maize) as a grain or masa; Note: Whole-grain corn and corn masa are separate foods and are not covered here.
- Sustainability and conservation
- Not assessed.
Photographs
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 |
|---|---|---|---|---|
| Polyunsaturated fat (mostly linoleic acid, omega-6) | fatty acid | Corn oil USDA: 54.7 g per 100 g, of which linoleic acid 53.2 g and alpha-linolenic acid (omega-3 ALA) 1.2 g | The main fat in corn oil. Replacing saturated fat with it lowers LDL cholesterol (American Heart Association advisory). 18 9 4 | Human data |
| Monounsaturated fat | fatty acid | Corn oil USDA: 27.6 g per 100 g | Part of the unsaturated fat that replaces saturated fat in swap studies. 18 | Nutrient database |
| Saturated fat | fatty acid | Corn oil USDA: 12.9 g per 100 g | The AHA advisory links swapping saturated for unsaturated fat with lower LDL. 18 9 | Human data |
| Vitamin E (alpha-tocopherol) | vitamin | Corn oil USDA: 14.3 mg per 100 g | A nutrient present in the oil. MedlinePlus lists corn oil among vegetable oil sources of vitamin E. No trial of corn oil as a vitamin E source was read. 18 16 | Nutrient database |
| Vitamin K (phylloquinone) | vitamin | Corn oil USDA: 1.9 mcg per 100 g | A very small amount; see the warfarin note on the Safety tab. 18 | Nutrient database |
| Phytosterols | plant sterol | Corn oil No value in the USDA item read. | The FDA letter notes the petitioner named phytosterols as a possible contributor to the cholesterol effect, and says there is no scientific evidence that phytosterols in corn oil provide the claimed benefit. 13 | Regulator statement |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| LDL cholesterol (swap of saturated for unsaturated fat) | Not specified in the sources read | The AHA advisory says replacing saturated with unsaturated fats lowers LDL, a cause of atherosclerosis. 9 | Human data |
| Blood pressure and vessel function with repeatedly heated oil | Not specified | In rats, diets containing repeatedly heated corn oil raised blood pressure and inflammation markers and weakened blood vessel relaxation. 2 | Animal research |
Absorption, metabolism and elimination
- Absorption
- Not researched.
- Distribution
- Not found.
- Metabolism
- Not found.
- Elimination
- Not found.
- Bioavailability
- Not established on this page.
Isolated compounds versus whole extracts
The human trials are on corn oil eaten as a food fat, usually baked into muffins, rolls and yogurt, and in large amounts. The pooled heart-event and omega-6 analyses cover polyunsaturated fat or linoleic acid from many sources, not corn oil alone. They do not cover corn kernels, corn masa or supplements.
Nutritional composition
Nutrition from USDA FoodData Central, Oil, corn, industrial and retail, all purpose salad or cooking (FDC 171029, SR Legacy). Per 100 g: 900 kcal; 100 g total fat; 12.9 g saturated, 27.6 g monounsaturated, 54.7 g polyunsaturated (53.2 g linoleic acid, 1.2 g ALA); 14.3 mg vitamin E; 1.9 mcg vitamin K; 0 mg cholesterol. USDA's household portion is 1 tablespoon (13.6 g): about 122 kcal, 13.6 g fat, 1.8 g saturated, 3.8 g monounsaturated, 7.4 g polyunsaturated, 1.9 mg vitamin E and 0.26 mcg vitamin K. Source note: copied from our stored summary of that USDA record; the record was not re-opened on 2026-10-26 because the USDA service was rate-limited. Oil has no protein, carbohydrate or fibre. The USDA vitamin D value for this item looks like a data error for a plant oil and is not used.
1 high certainty1 moderate certainty1 mixed findings4 low certainty1 very low certainty
What was looked at
The 8 benefits and uses checked for Corn Oil, each with how strong the evidence is. Tap one to open it.
- Fat profile and vitamin E (nutrient content)High certainty
- LDL cholesterol compared with extra virgin olive oilLow certainty
- Cholesterol compared with coconut oilVery low certainty
- Heart disease when polyunsaturated oil replaces saturated fatModerate certainty
- FDA label claim for heart diseaseLow certainty
- Deaths: the Minnesota Coronary Experiment (corn-oil diet)Mixed findings
- Heart events with more omega-6 fatLow certainty
- Inflammation markers (linoleic acid)Low certainty
Lab markers tracked in the studies
LDL cholesterolNon-HDL cholesterol and apolipoprotein BTriglyceridesTotal (serum) cholesterolC-reactive protein (CRP)
What is Corn Oil good for?
The main studied uses and how strong the human evidence is for each. Most results are about corn oil replacing other fats in the diet, and most are blood tests, not health events. Trial amounts were large and are not advice.
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.
Fat profile and vitamin E (nutrient content)
High certaintyBy USDA data, corn oil is 100% fat. It is mostly polyunsaturated fat (about 55 g of every 100 g, nearly all of it omega-6 linoleic acid), with about 13 g of saturated fat. One tablespoon (13.6 g) has about 122 kcal and about 1.9 mg of vitamin E.
3 studiesRefined corn oil, industrial and retail, all-purpose salad or cooking…
Studies, doses and limits
What the trials found
No trial was read showing that the vitamin E in corn oil corrects a shortfall. MedlinePlus lists corn oil among vegetable oils that contain vitamin E. NHS lists corn oil among vegetable oils that provide omega-6 fats.
Results
Corn oil is a polyunsaturated, low-saturated-fat oil with some vitamin E, on paper. It supplies no protein, carbohydrate or fibre.
Effect sizes as reported
USDA per 100 g: 900 kcal; saturated fat 12.9 g; monounsaturated 27.6 g; polyunsaturated 54.7 g; linoleic acid 53.2 g; vitamin E 14.3 mg; vitamin K 1.9 mcg. One tablespoon (13.6 g) is the same numbers times 0.136.
Why this rating
High that the oil contains about these amounts (USDA data). The USDA record was not re-opened on the day this page was built (the USDA service was rate-limited), so the numbers come from our stored summary of that record. No health effect is claimed from the numbers alone.
Form and dose studied
Refined corn oil, industrial and retail, all-purpose salad or cooking, as listed by USDA. Unrefined corn oil and corn-oil margarine were not read.
Who was studied
General adult diet.
Limits
Nutrient facts, not trials. The tablespoon is USDA's household portion, not a recommendation.
Why researchers looked
Oils are judged first on their fat mix, because swapping saturated fat for unsaturated fat is the main diet advice for heart health.
Traditional use
Not a traditional remedy. It is a refined cooking and salad oil.
Proposed mechanism Nutrient database
These are nutrient amounts in the oil, from a USDA table.
A proposed mechanism does not show that the effect happens in people.
Oils are energy dense: about 122 kcal in a tablespoon.
LDL cholesterol compared with extra virgin olive oil
Low certaintyIn one controlled feeding trial in 54 adults with raised LDL, foods made with corn oil lowered LDL ('bad') cholesterol more than foods made with extra virgin olive oil over 21 days. The amount was large and the trial was short. It measured blood tests, not heart attacks.
2 studiesCorn oil baked into muffins, rolls and yogurt in a controlled diet. T…
Studies, doses and limits
What the trials found
A double-blind crossover trial gave 54 adults (LDL 130 to 199 mg/dL) foods made with 4 tablespoons a day of corn oil or extra virgin olive oil, 21 days each. LDL fell 10.9% with corn oil and 3.5% with olive oil. Total and non-HDL cholesterol also fell more with corn oil. Triglycerides rose less with corn oil (3.5% vs 13.0%). A second report of the same trial found corn oil lowered apolipoprotein B and LDL particle number more, while apolipoprotein A1 rose more with olive oil.
Results
In this one short trial, corn oil gave larger falls in LDL and related cholesterol measures than olive oil.
Effect sizes as reported
LDL -10.9% vs -3.5%; total cholesterol -8.2% vs -1.8%; non-HDL -9.3% vs -1.6% (all P<.001). Non-HDL -0.39 vs -0.04 mmol/L in the second report. HDL did not differ.
Why this rating
Low because it is one trial (reported in two papers), 54 people, 21 days per oil, a very large amount of oil, and blood markers only. The rating is ours; the abstracts do not give a GRADE rating. The abstracts do not say who paid for the trial.
Form and dose studied
Corn oil baked into muffins, rolls and yogurt in a controlled diet. Trial amounts, not advice.
Who was studied
Adults with LDL cholesterol 130 to 199 mg/dL.
Limits
The trial amount (4 tablespoons, 54 g a day) is far above a typical serving. Olive oil has other evidence not covered here. LDL is a marker, not a health outcome.
Why researchers looked
Corn oil is mostly polyunsaturated fat and olive oil is mostly monounsaturated fat, and researchers asked which changes blood cholesterol more.
Proposed mechanism Authoritative guidance
Not tested in these reports. The usual explanation is that unsaturated fat replacing saturated fat lowers LDL, as the American Heart Association advisory describes.
A proposed mechanism does not show that the effect happens in people.
At trial amounts the oil adds many calories, so the trials were run on weight-maintenance diets.
Cholesterol compared with coconut oil
Very low certaintyA small preliminary trial in 25 adults found foods made with corn oil gave a better blood fat profile than foods made with coconut oil over 4 weeks. The change in LDL, the main outcome, narrowly missed statistical significance.
1 studiesCorn oil or coconut oil in muffins and rolls. Trial amounts, not advi…
Studies, doses and limits
What the trials found
In a randomized crossover trial, 12 men and 13 women ate foods with about 54 g a day of corn oil or coconut oil for 4 weeks each. LDL changed -2.7% with corn oil and +4.6% with coconut oil (P=0.06). Non-HDL cholesterol changed -3.0% vs +5.8% (P=0.034). hs-CRP and glucose handling did not differ.
Results
Corn oil looked better than coconut oil for blood fats, but the trial was small and its main result was not statistically significant.
Effect sizes as reported
LDL -2.7% vs +4.6% (P=0.06); non-HDL -3.0% vs +5.8% (P=0.034); total cholesterol -0.5% vs +7.1% (P=0.06).
Why this rating
Very low: 25 people, the authors call the trial preliminary, and the main outcome was not significant. The rating is ours.
Form and dose studied
Corn oil or coconut oil in muffins and rolls. Trial amounts, not advice.
Who was studied
Adults with LDL cholesterol 115 to under 190 mg/dL.
Limits
Small, short, large oil amount, blood markers only. Funding is not stated in the abstract.
Why researchers looked
Coconut oil is high in saturated fat, and few trials had compared it with a polyunsaturated oil such as corn oil.
Proposed mechanism Not assessed
Not tested.
A proposed mechanism does not show that the effect happens in people.
None specific beyond calories.
Heart disease when polyunsaturated oil replaces saturated fat
Moderate certaintyPooled trials found fewer coronary events when polyunsaturated fat replaced saturated fat: 19% fewer in 8 trials. The American Heart Association says about 30% fewer cardiovascular events in such trials. These results are about the fat swap, not corn oil on its own.
2 studiesPolyunsaturated vegetable oils in place of saturated fat, as food.
Studies, doses and limits
What the trials found
A 2010 pooled analysis of 8 randomized trials (13,614 people, 1,042 coronary events) found a 19% lower risk of coronary events when polyunsaturated fat replaced saturated fat (risk ratio 0.81), about 10% lower for each 5% of energy swapped. The 2017 American Heart Association advisory says trials replacing saturated fat with polyunsaturated vegetable oil reduced cardiovascular disease by about 30%. The abstracts do not name which oils were used or separate corn oil. The Minnesota trial on the Evidence tab is a more mixed result for corn oil in particular.
Results
Moderate support for the swap in general. Not shown for corn oil alone.
Effect sizes as reported
Coronary events: risk ratio 0.81 (95% CI 0.70 to 0.95). Per 5% of energy: 0.90 (0.83 to 0.97).
Why this rating
Moderate for the swap (pooled randomized trials and an AHA advisory); the rating is ours. It does not apply to corn oil alone, and a 2016 re-analysis of one corn-oil trial did not show fewer deaths (see Evidence tab).
Form and dose studied
Polyunsaturated vegetable oils in place of saturated fat, as food.
Who was studied
Adults in long trials (at least 1 year).
Limits
Trial diets differed. Corn oil was not separated. Abstracts only.
Why researchers looked
Corn oil is a common polyunsaturated oil, and the question is whether swapping it for saturated fat prevents heart disease.
Proposed mechanism Authoritative guidance
Replacing saturated with unsaturated fats lowers LDL cholesterol, a cause of atherosclerosis (AHA advisory).
A proposed mechanism does not show that the effect happens in people.
None specific.
FDA label claim for heart disease
Low certaintyIn 2007 the US FDA said it would allow a very cautious heart-health label on corn oil. It rated the evidence as 'very low' comfort and said there is 'little scientific evidence' behind the claim, which depends on corn oil replacing a similar amount of saturated fat without adding calories.
1 studiesCorn oil and corn-oil-containing products, as labelled.
Studies, doses and limits
What the trials found
The FDA letter (26 March 2007) says the evidence is credible, but because only two small intervention studies showed benefit and not every study did, it represents a very low level of comfort among qualified scientists. The wording it would allow says 'very limited and preliminary scientific evidence suggests' that corn oil may reduce heart disease risk due to its unsaturated fat, and 'FDA concludes that there is little scientific evidence supporting this claim'.
Results
A regulator's cautious label wording, not a finding that corn oil prevents heart disease.
Why this rating
Low: the FDA itself rated its comfort 'very low'. The letter is from 2007 and later FDA changes were not checked.
Form and dose studied
Corn oil and corn-oil-containing products, as labelled.
Who was studied
General US population.
Limits
From 2007, based on studies older than the trials above. Read from an archived copy.
Why researchers looked
A food company petitioned the FDA to allow a heart-health claim for corn oil.
Proposed mechanism Regulator letter
The FDA letter attributes the effect to the unsaturated fat content of corn oil.
A proposed mechanism does not show that the effect happens in people.
FDA concluded the use of unsaturated fat from corn oil at the levels needed for the claim was safe and lawful.
Deaths: the Minnesota Coronary Experiment (corn-oil diet)
Mixed findingsIn a 1968-73 trial of 9,423 people in a nursing home and state mental hospitals, a diet using corn oil and corn-oil margarine in place of saturated fat lowered cholesterol but did not lower deaths, according to data recovered decades later. This does not match the cholesterol benefit seen in other studies, so the picture for corn oil is mixed.
1 studiesCorn oil and corn-oil polyunsaturated margarine as the main fats in a…
Studies, doses and limits
What the trials found
The corn-oil diet lowered serum cholesterol by 13.8% versus 1.0% on the control diet. Kaplan-Meier graphs showed no survival benefit in the whole group or any prespecified subgroup, and autopsies showed no benefit for coronary atherosclerosis or heart attacks. A pooled analysis of five trials of this kind (10,808 people) found no lower coronary death (risk ratio 1.13) or all-cause death (1.07), with wide uncertainty. The authors said incomplete publication had contributed to overestimating the benefit of replacing saturated fat with linoleic-rich oils.
Results
Cholesterol went down; deaths did not. The result applies to a whole diet using corn oil and corn-oil margarine in institutions, not to corn oil alone.
Effect sizes as reported
Serum cholesterol -13.8% vs -1.0%. Coronary heart disease deaths RR 1.13 (95% CI 0.83 to 1.54); all-cause deaths RR 1.07 (0.90 to 1.27).
Why this rating
Mixed: this randomized trial did not show fewer deaths, while a pooled analysis of other trials (8 trials, 2010) found fewer coronary events when polyunsaturated fat replaced saturated fat. The rating is ours.
Form and dose studied
Corn oil and corn-oil polyunsaturated margarine as the main fats in a whole diet.
Who was studied
Adults aged 20 to 97 living in institutions, 1968-73.
Limits
Old trial, institutional setting, recovered data, corn oil mixed with corn-oil margarine. The paper drew published comments and an erratum that were not read. Only the abstract was read.
Why researchers looked
It was designed to test whether lowering cholesterol with a linoleic-rich vegetable oil reduces heart disease and death.
Proposed mechanism Not assessed
Not tested.
A proposed mechanism does not show that the effect happens in people.
The paper also reports an association of 22% higher risk of death for each 30 mg/dL fall in serum cholesterol in adjusted models. This is an association, not proof that corn oil caused harm.
Heart events with more omega-6 fat
Low certaintyA Cochrane review of 19 trials (6,461 people) found low-quality evidence that eating more omega-6 fat (corn oil is mostly linoleic acid, an omega-6) may make little or no difference to deaths or cardiovascular events. It may lower heart attacks a little, and total cholesterol falls a little.
1 studiesOmega-6 fats (linoleic acid) from various sources, not corn oil alone.
Studies, doses and limits
What the trials found
The 2018 review included trials of 1 to 8 years where omega-6 fat usually displaced saturated or monounsaturated fat. All-cause deaths: risk ratio 1.00. Cardiovascular events: 0.97. Heart attack: 0.88 (confidence interval 0.76 to 1.02), low-quality evidence. Total cholesterol fell 0.33 mmol/L (high-quality evidence). Body mass index changed little.
Results
Little or no difference in deaths or overall cardiovascular events; a small fall in total cholesterol.
Effect sizes as reported
All-cause deaths RR 1.00 (0.88 to 1.12); cardiovascular events RR 0.97 (0.81 to 1.15); total cholesterol -0.33 mmol/L (-0.50 to -0.16).
Why this rating
Low, using the reviewers' own wording for deaths and events ('low-quality evidence', GRADE). Only 3 of 19 trials were at low risk of bias.
Form and dose studied
Omega-6 fats (linoleic acid) from various sources, not corn oil alone.
Who was studied
Adults with or without cardiovascular disease.
Limits
Not specific to corn oil. Only the abstract was read.
Why researchers looked
Omega-6 fats are common in vegetable oils, and their effect on heart disease has been debated.
Proposed mechanism Not assessed
Not tested in the review.
A proposed mechanism does not show that the effect happens in people.
None specific.
Inflammation markers (linoleic acid)
Low certaintyA pooled analysis of 30 trials (1,377 people) found no significant effect of eating more linoleic acid, the main fat in corn oil, on blood inflammation markers overall. This does not show an anti-inflammatory benefit either.
1 studiesLinoleic acid from various foods and supplements.
Studies, doses and limits
What the trials found
The 2017 analysis found no significant change in tumor necrosis factor, interleukin-6, adiponectin, monocyte chemoattractant protein 1, fibrinogen, plasminogen activator inhibitor-1 or adhesion molecules. For CRP, pooled results were not significant (SMD 0.09, 95% CI -0.05 to 0.24), but a subgroup analysis hinted that a much larger increase in linoleic acid might raise CRP.
Results
No clear effect on blood inflammation markers.
Effect sizes as reported
CRP SMD 0.09 (95% CI -0.05 to 0.24); interleukin-6 SMD 0.11 (-0.07 to 0.29); tumor necrosis factor SMD -0.01 (-0.19 to 0.17).
Why this rating
Low: linoleic acid came from many sources, not corn oil alone, and for some markers there were few trials. The rating is ours.
Form and dose studied
Linoleic acid from various foods and supplements.
Who was studied
Adults in 30 randomized trials.
Limits
Markers only, not diseases. Not corn oil specific. Only the abstract was read.
Why researchers looked
A popular claim says that omega-6 seed oils cause inflammation, so researchers tested linoleic acid directly.
Proposed mechanism Not assessed
Not tested.
A proposed mechanism does not show that the effect happens in people.
The CRP subgroup hint is a caution that very large increases were not shown to be neutral.
Connections to the rest of health
How Corn Oil 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
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Preventive Wellness | High certainty | Fat profile and vitamin E (nutrient content): By USDA data, corn oil is 100% fat. It is mostly polyunsaturated fat (about 55 g of every 100 g, nearly all of it omega-6 linoleic acid), with about 13 g of saturated fat. One tablespoon (13.6 g) has about 122 kcal and about 1.9 mg of vitamin E. | 18 16 17 | |
| Cholesterol Balance | Low certainty | LDL cholesterol compared with extra virgin olive oil: In one controlled feeding trial in 54 adults with raised LDL, foods made with corn oil lowered LDL ('bad') cholesterol more than foods made with extra virgin olive oil over 21 days. The amount was large and the trial was short. It measured blood tests, not heart attacks. Cholesterol compared with coconut oil: A small preliminary trial in 25 adults found foods made with corn oil gave a better blood fat profile than foods made with coconut oil over 4 weeks. The change in LDL, the main outcome, narrowly missed statistical significance. | 4 5 6 | |
| Heart Health | Low certainty | LDL cholesterol compared with extra virgin olive oil: In one controlled feeding trial in 54 adults with raised LDL, foods made with corn oil lowered LDL ('bad') cholesterol more than foods made with extra virgin olive oil over 21 days. The amount was large and the trial was short. It measured blood tests, not heart attacks. Heart disease when polyunsaturated oil replaces saturated fat: Pooled trials found fewer coronary events when polyunsaturated fat replaced saturated fat: 19% fewer in 8 trials. The American Heart Association says about 30% fewer cardiovascular events in such trials. These results are about the fat swap, not corn oil on its own. | 4 5 7 9 3 | |
| Heart Health | Low certainty | FDA label claim for heart disease: In 2007 the US FDA said it would allow a very cautious heart-health label on corn oil. It rated the evidence as 'very low' comfort and said there is 'little scientific evidence' behind the claim, which depends on corn oil replacing a similar amount of saturated fat without adding calories. | 13 | |
| Heart Health | Mixed findings | Deaths: the Minnesota Coronary Experiment (corn-oil diet): In a 1968-73 trial of 9,423 people in a nursing home and state mental hospitals, a diet using corn oil and corn-oil margarine in place of saturated fat lowered cholesterol but did not lower deaths, according to data recovered decades later. This does not match the cholesterol benefit seen in other studies, so the picture for corn oil is mixed. | 8 | |
| Inflammation Balance | Low certainty | Inflammation markers (linoleic acid): A pooled analysis of 30 trials (1,377 people) found no significant effect of eating more linoleic acid, the main fat in corn oil, on blood inflammation markers overall. This does not show an anti-inflammatory benefit either. | 10 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Cardiovascular System | Biological association | High certainty | Studied for: Fat profile and vitamin E (nutrient content) Studied for: LDL cholesterol compared with extra virgin olive oil | 18 16 17 4 5 6 7 9 13 8 3 |
| Immune System | Biological association | Low certainty | Studied for: Inflammation markers (linoleic acid) | 10 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| LDL cholesterol | Limited human evidence (blood measure) | Lower with corn oil than with olive oil in one 21-day trial in 54 adults with raised LDL; large amounts were used. Preparation or compound: Corn oil as food |
4 5 6 | |
| LDL cholesterol | Biological association | Low certainty | Measured in trials: lowered (more than olive oil or coconut oil in short trials). A lab change is not the same as a health benefit. | 4 5 6 |
| Non-HDL cholesterol and apolipoprotein B | Biological association | Low certainty | Measured in trials: lowered (more than olive oil or coconut oil in short trials). A lab change is not the same as a health benefit. | 5 6 |
| Triglycerides | Biological association | Very low certainty | Measured in trials: mixed (rose less than with olive oil; fell slightly versus coconut oil). A lab change is not the same as a health benefit. | 4 6 |
| Total (serum) cholesterol | Biological association | Moderate certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 8 3 |
| C-reactive protein (CRP) | Biological association | Low certainty | Measured in trials: no significant change. A lab change is not the same as a health benefit. | 10 6 |
K. Biological pathways
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Linoleic acid (omega-6) | Preliminary mechanism | Human | Corn oil is mostly linoleic acid; pooled trials found little or no change in deaths or cardiovascular events and no significant change in inflammation markers overall. | 18 3 10 |
| LDL cholesterol | Preliminary mechanism | Human | Lower with corn oil than with olive oil in one 21-day feeding trial in 54 adults with raised LDL. | 4 5 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Polyunsaturated fat (mostly linoleic acid, omega-6) | Biological association | Human | The main fat in corn oil. Replacing saturated fat with it lowers LDL cholesterol (American Heart Association advisory). Preparation or compound: Corn oil |
18 9 4 |
| Monounsaturated fat | Biological association | Nutrient database | Part of the unsaturated fat that replaces saturated fat in swap studies. Preparation or compound: Corn oil |
18 |
| Saturated fat | Biological association | Human | The AHA advisory links swapping saturated for unsaturated fat with lower LDL. Preparation or compound: Corn oil |
18 9 |
| Vitamin E (alpha-tocopherol) | Biological association | Nutrient database | A nutrient present in the oil. MedlinePlus lists corn oil among vegetable oil sources of vitamin E. No trial of corn oil as a vitamin E source was read. Preparation or compound: Corn oil |
18 16 |
| Vitamin K (phylloquinone) | Biological association | Nutrient database | A very small amount; see the warfarin note on the Safety tab. Preparation or compound: Corn oil |
18 |
| Phytosterols | Biological association | Regulator statement | The FDA letter notes the petitioner named phytosterols as a possible contributor to the cholesterol effect, and says there is no scientific evidence that phytosterols in corn oil provide the claimed benefit. Preparation or compound: Corn oil |
13 |
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 changed in 1 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Corn Oil. 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 started from our existing corn oil summary, re-read the FDA corn oil letter, FDA allergen and trans fat pages, NHS and MedlinePlus pages, checked the plant name against GBIF, and re-checked ten PubMed records by summary and abstract. Items we could not verify are flagged in the research gaps.
Study library: every study we checked 18
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Chiang 2022 Particulate matters, aldehydes, and polycyclic aromatic hydrocarbons produced from deep-frying emissions: comparisons of three cooking oils with distinct fatty acid profiles. NPJ Sci Food · PMID 35660737 · DOI |
Simulated kitchen laboratory comparison n/a |
3 oils Not a human study |
Palm oil gave the most particles and PAHs; soybean oil gave the most aldehydes, which rose with the share of polyunsaturated fatty acids in the oil. Olive oil gave the least toxic emissions. Corn oil was not tested. Not applicable (Not applicable) Methods, limits and fundingOutcomes: Fine particles, aldehydes and polycyclic aromatic hydrocarbons in cooking emissions Limitations: Corn oil was not one of the three oils. It cannot be used to say how corn oil behaves when heated. Only the abstract was read. Funding and conflicts: Funding is not stated in the abstract. Read: abstract | |
| Das 2017 Changes in blood pressure, vascular reactivity and inflammatory biomarkers following consumption of heated corn oil. Pak J Pharm Sci · PMID 29084680 |
Animal feeding experiment animal |
30 male Sprague-Dawley rats, 5 groups Rats |
Rats fed once-, five- and ten-times heated corn oil had higher blood pressure than controls, with higher CRP and adhesion molecules and weaker blood vessel relaxation. The authors concluded that repeatedly heated corn oil may predispose to hypertension in rats. Not given in the abstract (Not given in the abstract) Methods, limits and fundingOutcomes: Blood pressure, CRP, soluble adhesion molecules, blood vessel reactivity Limitations: Animal study in rats with a very large share of oil in the diet. It cannot be applied to people or to normal home cooking. No human study of heated corn oil was found. Only the abstract was read. Funding and conflicts: Funding is 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 and meta analysis of randomized trials (Cochrane) |
19 trials, 6,461 participants, followed 1 to 8 years Adults with or without cardiovascular disease (12 trials of linoleic acid; 7 of gamma-linolenic acid) |
Low-quality evidence that more omega-6 fat may make little or no difference to deaths from any cause or to cardiovascular events. Very low-quality evidence leaves cardiovascular death, coronary events and stroke uncertain. Heart attacks may be a little lower (low-quality evidence). High-quality evidence says total serum cholesterol falls a little in the long term; LDL, HDL and triglycerides may change little. All-cause deaths RR 1.00; cardiovascular events RR 0.97; heart attack RR 0.88; total cholesterol -0.33 mmol/L (All-cause deaths 0.88 to 1.12; cardiovascular events 0.81 to 1.15; heart attack 0.76 to 1.02; total cholesterol -0.50 to -0.16) Methods, limits and fundingOutcomes: All-cause deaths, cardiovascular deaths and events, blood fats, body mass index Limitations: Not specific to corn oil; many trials used other omega-6 sources. Only 3 of 19 trials were at low risk of bias. Only the abstract was read. Funding and conflicts: Cochrane review; the abstract reports Non-US Government research support. Read: abstract | |
| Maki 2015 Corn oil improves the plasma lipoprotein lipid profile compared with extra-virgin olive oil consumption in men and women with elevated cholesterol: results from a randomized controlled feeding trial. J Clin Lipidol · PMID 25670360 · DOI |
Randomized, double blind, crossover controlled feeding trial |
54 adults Men and women with LDL cholesterol 130 to 199 mg/dL and triglycerides up to 350 mg/dL |
Corn oil lowered LDL, total and non-HDL cholesterol and the total-to-HDL ratio more than olive oil. Triglycerides rose less with corn oil. HDL cholesterol did not differ between the two. LDL -10.9% vs -3.5%; total cholesterol -8.2% vs -1.8%; non-HDL -9.3% vs -1.6%; total/HDL -4.4% vs +0.5% (all P<.001 vs olive oil); triglycerides +3.5% vs +13.0% (P=.007); HDL -3.4% vs -1.7% (not significant) (Not given in the abstract) Methods, limits and fundingOutcomes: LDL cholesterol, total cholesterol, non-HDL cholesterol, HDL cholesterol, total-to-HDL ratio, triglycerides Limitations: Short (21 days per oil). The amount used was large (4 tablespoons a day), far above a typical home serving. Cholesterol blood markers only, not heart events. Both oils were given inside a controlled low-saturated-fat diet. Only the abstract was read. Funding and conflicts: Funding is not stated in the abstract. The abstract does not say who paid for the trial. Read: abstract | |
| Maki 2017 Corn oil intake favorably impacts lipoprotein cholesterol, apolipoprotein and lipoprotein particle levels compared with extra-virgin olive oil. Eur J Clin Nutr · PMID 27677368 · DOI |
Randomized, double blind, crossover controlled feeding trial (second analysis of the same trial as p25670360) |
54 completers Men and women, as in the first report of this trial |
Corn oil lowered total cholesterol, LDL, VLDL and non-HDL cholesterol, apolipoprotein B and LDL particle number more than olive oil. HDL cholesterol did not differ, but apolipoprotein A1 rose more with olive oil. Non-HDL cholesterol -0.39 vs -0.04 mmol/L (P<0.001); apolipoprotein A1 +4.6 mg/dL with olive oil vs +0.7 mg/dL with corn oil (P=0.016) (Not given in the abstract) Methods, limits and fundingOutcomes: Lipoprotein cholesterol subfractions, apolipoprotein A1 and B, LDL particle concentration Limitations: Same people and same short trial as the 2015 report, so it is not an independent second trial. Large amount of oil. Blood markers only. Only the abstract was read. Funding and conflicts: Funding is not stated in the abstract. Read: abstract | |
| Maki 2018 Corn Oil Lowers Plasma Cholesterol Compared with Coconut Oil in Adults with Above-Desirable Levels of Cholesterol in a Randomized Crossover Trial. J Nutr · PMID 30204921 · DOI |
Preliminary randomized crossover trial (registered NCT03202654) |
25 adults (12 men, 13 women) Adults with LDL cholesterol from 115 to under 190 mg/dL, mean age 45.2 years |
Foods made with corn oil gave a more favorable blood fat profile than coconut oil. Non-HDL cholesterol differed significantly; LDL and total cholesterol differences came close to significance. hs-CRP and glucose measures did not differ. LDL -2.7% vs +4.6% (P=0.06, main outcome); non-HDL -3.0% vs +5.8% (P=0.034); total cholesterol -0.5% vs +7.1% (P=0.06) (Not given in the abstract) Methods, limits and fundingOutcomes: LDL cholesterol (main outcome), non-HDL, total and HDL cholesterol, triglycerides, hs-CRP, glucose handling Limitations: The authors call it preliminary. Small (25 people). The main outcome, LDL, did not reach statistical significance. Large amount of oil, short trial, blood markers only. Only the abstract was read. Funding and conflicts: Funding is 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 and meta analysis of randomized trials |
8 trials, 13,614 participants, 1,042 coronary events Adults in trials lasting at least 1 year (searched to June 2009) |
Pooled coronary events were 19% lower when polyunsaturated fat replaced saturated fat. Trials that ran longer showed greater benefit. The abstract does not say which oils were used, and corn oil on its own was not separated. Risk ratio 0.81; about 10% lower risk for each 5% of energy swapped (risk ratio 0.90) (95% CI 0.70 to 0.95 (overall); 0.83 to 0.97 (per 5% of energy)) Methods, limits and fundingOutcomes: Coronary heart disease events (heart attack and/or cardiac death) Limitations: Tests a fat swap, not corn oil by itself. Trial diets differed. Only the abstract was read. Funding and conflicts: Funding is not stated in the abstract. 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 |
Recovered data analysis of a double blind randomized trial, plus systematic review and meta analysis |
9,423 randomized (2,355 on the diets for a year or more; 149 autopsy files); meta-analysis of 5 trials, 10,808 people Men and women aged 20 to 97 in one nursing home and six state mental hospitals in Minnesota, 1968-73 |
The corn-oil diet lowered serum cholesterol but did not lower deaths in the whole group or in any prespecified subgroup. There was no benefit for coronary atherosclerosis or heart attacks at autopsy. In pooled trials of this kind, deaths from coronary heart disease and from all causes were not lower. The authors concluded that incomplete publication had contributed to overestimating the benefit of replacing saturated fat with linoleic-rich vegetable oils. Serum cholesterol -13.8% vs -1.0% (P<0.001). Coronary heart disease deaths RR 1.13; all-cause deaths RR 1.07 (pooled 5 trials). Association: hazard ratio 1.22 for death per 30 mg/dL fall in serum cholesterol. (Coronary heart disease deaths 95% CI 0.83 to 1.54; all-cause deaths 0.90 to 1.27; hazard ratio 1.14 to 1.32) Methods, limits and fundingOutcomes: Death from all causes; link between change in serum cholesterol and death; coronary atherosclerosis and heart attacks at autopsy Limitations: An old trial (1968-73) in institutionalised adults, with data recovered decades later. The diet included corn oil and corn-oil margarine together, so corn oil is not tested on its own. The hazard ratio is an association, not proof of harm. The paper drew published comments and an erratum, which were not read. Only the abstract was read. Funding and conflicts: Funding listed by PubMed as NIH and US public health service grants; the abstract does not state the details. Read: abstract | |
| Sacks 2017 Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association. Circulation · PMID 28620111 · DOI |
Expert advisory review n/a |
Not applicable General population |
The advisory says trials that cut saturated fat and replaced it with polyunsaturated vegetable oil reduced cardiovascular disease by about 30%, and that replacing saturated fat with unsaturated fats lowers LDL cholesterol. It recommends the shift within an overall healthful diet such as DASH or Mediterranean. About 30% fewer cardiovascular events in the trials it reviewed (Not given in the abstract) Methods, limits and fundingOutcomes: Cardiovascular disease Limitations: Advice about fats in general, not corn oil specifically. Only the abstract was read. Funding and conflicts: Written by the American Heart Association; no funding statement in the abstract. 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 and meta analysis of randomized trials |
30 trials, 1,377 participants Adults in randomized trials |
Higher linoleic acid intake had no significant effect on blood inflammatory markers overall. For CRP, subgroup analysis suggested that a larger increase in linoleic acid might raise CRP. CRP SMD 0.09; tumor necrosis factor SMD -0.01; interleukin-6 SMD 0.11 (CRP -0.05 to 0.24; tumor necrosis factor -0.19 to 0.17; interleukin-6 -0.07 to 0.29) Methods, limits and fundingOutcomes: Inflammatory markers: cytokines, C-reactive protein (CRP), fibrinogen, adhesion molecules Limitations: About linoleic acid from many sources, not corn oil alone. Few trials for some markers. Only the abstract was read. Funding and conflicts: Funding is not stated in the abstract. Read: abstract | |
| s-fda-allergen-qa FDA: Questions and Answers Regarding Food Allergens, Including the Food Allergen Labeling Requirements (Edition 5), guidance for industry · Source |
Regulator guidance n/a |
Methods, limits and fundingRead: excerpt | ||
| s-fda-allergens FDA: Food Allergies · Source |
Regulator page n/a |
Methods, limits and fundingRead: full-text | ||
| s-fda-corn-qhc FDA: Qualified Health Claims, Letter of Enforcement Discretion, Corn Oil and Corn Oil-Containing Products and a Reduced Risk of Heart Disease (Docket 2006P-0243), 26 March 2007 · Source |
Regulator letter n/a |
Methods, limits and fundingRead: full-text | ||
| s-fda-trans-fat FDA: Trans Fat · Source |
Regulator page n/a |
Methods, limits and fundingRead: excerpt | ||
| s-gbif-zea-mays GBIF Backbone Taxonomy: species match for Zea mays · Source |
Taxonomy database n/a |
Methods, limits and fundingRead: full-text | ||
| s-medlineplus-vite-e MedlinePlus: Vitamin E in diet · Source |
Regulator page n/a |
Methods, limits and fundingRead: full-text | ||
| s-nhs-fats NHS: Different fats in our diet (fat: the facts) · Source |
Regulator page n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-171029 USDA FoodData Central: Oil, corn, industrial and retail, all purpose salad or cooking (FDC 171029, SR Legacy) · Source |
Food composition database n/a |
Methods, limits and fundingRead: summary-only |
What we do not know yet
- No trial of corn oil alone against heart attacks, strokes or deaths was found; the cholesterol results are blood measures, and the Minnesota diet combined corn oil with corn-oil margarine.
- The USDA record was not re-opened on the day this page was built; nutrient numbers come from our stored summary.
- Both olive-oil reports come from one trial of 54 people, and funding is not stated in the abstracts read.
- Corn allergy, pregnancy, breastfeeding, children, smoke point, heating in people, pesticide residues and genetic modification were not researched.
- Only abstracts were read for the studies, and the FDA letter was read from an archived 2007 copy.
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".
Metabolic 3
LDL cholesterol
Lowered (more than olive oil or coconut oil in short trials) in trials
The 'bad' cholesterol carried in the blood. Higher levels are linked to more heart disease.
Low certaintyResults and what it means
Why it was measured
It is the usual blood marker used in diet trials for heart risk.
Statistical vs. clinical meaning
A short-term change in a blood marker when corn oil is eaten in large amounts in place of other fats.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 4 | LDL -10.9% with corn oil vs -3.5% with extra virgin olive oil (P<.001) | 54 adults with LDL 130 to 199 mg/dL | Corn oil, 4 tablespoons a day in food, 21 days |
| 6 | LDL -2.7% with corn oil vs +4.6% with coconut oil (P=0.06, not significant) | 25 adults with LDL 115 to under 190 mg/dL | Corn oil, about 54 g a day in food, 4 weeks |
Triglycerides
Mixed (rose less than with olive oil; fell slightly versus coconut oil) in trials
A type of fat in the blood. High levels are linked to heart and pancreas problems.
Very low certaintyResults and what it means
Why it was measured
Reported in the corn oil trials alongside cholesterol.
Statistical vs. clinical meaning
Small, short-term differences between oils. Corn oil did not lower triglycerides compared with where people started in the olive oil trial.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 4 | Triglycerides rose 3.5% with corn oil vs 13.0% with olive oil (P=.007) | 54 adults | Corn oil, 4 tablespoons a day in food, 21 days |
| 6 | Triglycerides -2.1% with corn oil vs +6.0% with coconut oil (significance not given in the abstract) | 25 adults | Corn oil, about 54 g a day in food, 4 weeks |
Total (serum) cholesterol
Lowered in trials
All the cholesterol in the blood, including LDL and HDL.
Moderate certaintyResults and what it means
Why it was measured
It was the main marker used to judge the diet in the Minnesota trial and in the omega-6 review.
Statistical vs. clinical meaning
Cholesterol fell, but the Minnesota trial did not show fewer deaths.
Safety implication
Lower cholesterol was not shown to mean longer survival in the Minnesota trial.
| Study | Result | People | Product |
|---|---|---|---|
| 8 | Serum cholesterol -13.8% with the corn-oil diet vs -1.0% with the control diet | 9,423 adults in institutions | Corn oil and corn-oil margarine replacing saturated fat, whole diet |
| 3 | Total cholesterol -0.33 mmol/L (95% CI -0.50 to -0.16) with more omega-6 fat | 10 trials, 4,280 people | More omega-6 fat, mostly in place of saturated fat |
Other 2
Non-HDL cholesterol and apolipoprotein B
Lowered (more than olive oil or coconut oil in short trials) in trials
Non-HDL cholesterol is all cholesterol except the HDL ('good') type. Apolipoprotein B counts the particles that carry harmful cholesterol.
Low certaintyResults and what it means
Why it was measured
These markers capture more of the artery-clogging particles than LDL alone.
Statistical vs. clinical meaning
Same short trials as LDL; a blood marker, not a health outcome.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 5 | Non-HDL -0.39 vs -0.04 mmol/L with corn oil vs olive oil (P<0.001); apolipoprotein B and LDL particle number also fell more with corn oil | 54 adults | Corn oil, 54 g a day in food, 21 days |
| 6 | Non-HDL -3.0% vs +5.8% with corn oil vs coconut oil (P=0.034) | 25 adults | Corn oil, about 54 g a day in food, 4 weeks |
C-reactive protein (CRP)
No significant change in trials
A blood marker that rises with inflammation.
Low certaintyResults and what it means
Why it was measured
It is the most common inflammation marker in diet trials.
Statistical vs. clinical meaning
No clear change either way.
Safety implication
None established.
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
- High in calories. One tablespoon (13.6 g) has about 122 kcal by USDA data, like other oils. The trials on this page that lowered cholesterol swapped oils inside weight-maintenance diets, not extra oil on top of a usual diet. Nutrient database 18 4
- Corn is not a major US food allergen, but corn allergy exists. Corn is not on the FDA list of the nine major allergens (milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, sesame). We did not find a source on reactions to corn oil, so if you have a known corn allergy, ask an allergist. Authoritative guidance 12
- Heated corn oil: animal data only. A rat study found that diets with repeatedly heated corn oil raised blood pressure and inflammation markers. No human study of heated corn oil was found, and no study tested corn oil in a kitchen simulation. Nothing here shows that normal cooking with corn oil is harmful. Animal research 2 1
- Cholesterol fell, but deaths did not, in the Minnesota trial. A corn-oil diet lowered cholesterol in the Minnesota Coronary Experiment (1968-73), but recovered data did not show fewer deaths or fewer heart attacks, and the authors said incomplete publication had inflated past benefit estimates. This is not a finding of harm from corn oil. Human trial 8
Side effects 3
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| No harm from eating corn oil as an ordinary food was found in the sources read. The FDA's 2007 letter concluded that use of the unsaturated fat from corn oil at the levels needed for its cautious claim was safe and lawful. Absence of findings in the few sources read is not proof of safety. | No frequency data found. | not applicable Not applicable. | Not assessed 13 |
| Weight gain if oil adds calories on top of an unchanged diet (general to all oils). The FDA claim wording describes corn oil replacing a similar amount of saturated fat without adding calories. | Not quantified for corn oil. | mild Not described. | Nutrient database 18 |
| Possible rise in CRP at much higher linoleic acid intakes (a subgroup hint, not a firm finding). Overall, more linoleic acid did not change inflammation markers significantly. | Not quantified. | not established Not described. | Meta analysis subgroup 10 |
Liver
No liver injury from eating corn oil as a food was found in the sources read. Corn oil was not searched in LiverTox 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 Corn Oil supports liver health.
Medicines and supplements 2
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Warfarin and other vitamin K-sensitive blood thinners prescription | USDA lists 1.9 mcg of vitamin K per 100 g of corn oil, about 0.26 mcg in a tablespoon, which is very little. | No source read links ordinary corn oil intake with a change in warfarin control. | Nutrient database Not enough evidence 18 | If you take warfarin, keep your diet steady and tell your clinic about big changes in oils or leafy foods. |
| Cholesterol medicines (statins and others) prescription | Both lower LDL by different routes. | No interaction or added effect was found in the sources read. | Not assessed Not enough evidence | Ask your clinician or pharmacist before changing your fats if you are on cholesterol medicine. |
Who should check first 1
| Situation | Advice | Evidence |
|---|---|---|
| Known corn allergy | No source on corn oil reactions was found. People with a diagnosed corn allergy should ask their allergist before eating corn oil. | Not assessed |
Overdose, product quality and regulators
Summary. No toxicity from corn oil as an ordinary food was found. The only harm signal found was in rats fed repeatedly heated corn oil as 15% of their diet.
Animal. Rats fed once-heated or repeatedly heated corn oil for 16 weeks had higher blood pressure, higher CRP and adhesion molecules, and weaker blood vessel relaxation than controls. The authors recommend people avoid heated corn oil; we report this as animal data only.
High dose or long term signals. The Minnesota trial recovered-data analysis reported an association between larger cholesterol falls and higher death risk (hazard ratio 1.22 per 30 mg/dL). This is an association in one old trial, not proof that corn oil caused harm.
Overdose response. Not found.
Genotoxicity. Not researched.
Contamination (pesticide or solvent residues, aflatoxin, oxidation, genetic modification) was not researched for this page. Heating was covered only by one rat study.
Heating. No study of heated corn oil in people was found. One rat study found raised blood pressure with repeatedly heated corn oil. A laboratory comparison of frying emissions tested palm, olive and soybean oils, not corn oil. 2 1
Trans fat. USDA lists no trans fat value for this item. The FDA determined in 2015 that partially hydrogenated oils are no longer generally recognized as safe, and most uses ended in 2018. Corn-oil margarine is a different product from the oil. 18 14
Labeling. FDA guidance says the source of an oil, such as corn oil, must be part of its common or usual name in the ingredient list. 11
| Body | Action | Date |
|---|---|---|
| US FDA (United States) | Qualified health claim letter (enforcement discretion), 26 March 2007: very limited and preliminary evidence that corn oil replacing a similar amount of saturated fat, without more calories, may reduce heart disease risk. FDA rated its comfort in the evidence as very low and concluded the use was safe and lawful. source | 2007-03-26 |
| US FDA (United States) | Food allergies: lists nine major allergens (milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, sesame). Corn is not on the list. source | 2026-03-11 |
| US FDA (United States) | Allergen guidance (Edition 5): highly refined oils are exempt from the definition of major food allergen; the source of an oil must be part of its common or usual name in the ingredient list. source | |
| US FDA (United States) | Partially hydrogenated oils no longer generally recognized as safe (2015); manufacturers could not add them to most foods after 18 June 2018. source | 2024-04-30 |
When to get medical help
- Trouble breathing, wheezing, or swelling of the lips, face, tongue or throat after eating any food: call 911 or your local emergency number.
- Hives spreading over the body with vomiting or dizziness after a meal.
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 is corn oil?
Corn oil is a light cooking and salad oil made from corn (Zea mays). By USDA data, a tablespoon (13.6 g) has about 122 kcal, and the fat is mostly polyunsaturated.
What fats are in corn oil?
Per 100 g, USDA lists 12.9 g saturated fat, 27.6 g monounsaturated fat and 54.7 g polyunsaturated fat, of which 53.2 g is omega-6 linoleic acid and 1.2 g is the plant omega-3 ALA. It also has 14.3 mg of vitamin E.
Is corn oil healthy?
Does corn oil lower cholesterol?
In a 21-day feeding trial in 54 adults with raised LDL, corn oil lowered LDL by 10.9% against 3.5% for extra virgin olive oil. In a small 4-week trial, LDL changed -2.7% with corn oil and +4.6% with coconut oil, though that main result was not statistically significant. These were large amounts and blood tests only.
Is corn oil better than olive oil for cholesterol?
What was the Minnesota Coronary Experiment?
A 1968-73 trial in 9,423 people in a nursing home and state mental hospitals. A diet using corn oil and corn-oil margarine in place of saturated fat lowered cholesterol, but recovered data did not show fewer deaths or heart attacks. The authors said incomplete publication had inflated past estimates of benefit.
Does corn oil prevent heart disease?
Does corn oil cause inflammation?
A pooled analysis of 30 trials found no significant effect of more linoleic acid, the main fat in corn oil, on blood inflammation markers overall. One subgroup hinted that a much larger increase might raise C-reactive protein, so the question is not fully settled.
What does the FDA say about corn oil and heart disease?
In 2007 the FDA said it would allow a qualified label claim worded as 'very limited and preliminary scientific evidence'. It rated its comfort in the evidence as very low and said there is little scientific evidence for the claim, which depends on corn oil replacing a similar amount of saturated fat without adding calories.
Is corn oil a common food allergen?
Corn is not on the FDA list of nine major allergens (milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, sesame). We found no source on reactions to corn oil, so people with a corn allergy should ask an allergist. For trouble breathing or swelling of the face or throat after any food, call 911 or your local emergency number.
Is heated or fried corn oil harmful?
No human study was found. A rat study found higher blood pressure and inflammation markers when rats ate repeatedly heated corn oil as 15% of their diet. That is animal data and does not show harm from normal home cooking. A laboratory frying study tested palm, olive and soybean oils, not corn oil.
Does corn oil have trans fat or interact with medicines?
USDA lists no trans fat value for this item, and the FDA ruled in 2015 that partially hydrogenated oils are no longer generally recognized as safe. No medicine interaction was found in the sources read; if you take warfarin or cholesterol medicine, ask your clinic or pharmacist about big changes in your fats.
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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 started from our existing corn oil summary, re-read the FDA corn oil letter, FDA allergen and trans fat pages, NHS and MedlinePlus pages, checked the plant name against GBIF, and re-checked ten PubMed records by summary and abstract. Items we could not verify are flagged in the research gaps.
- 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. Funding is not stated in the abstracts read.
Sources 18
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Chiang KM, Xiu L, Peng CY, et al.. Particulate matters, aldehydes, and polycyclic aromatic hydrocarbons produced from deep-frying emissions: comparisons of three cooking oils with distinct fatty acid profiles.. NPJ Sci Food. 2022. PMID 35660737. DOI 10.1038/s41538-022-00143-5. (abstract)
- Das S, Hamsi MA, Kamisah Y, et al.. Changes in blood pressure, vascular reactivity and inflammatory biomarkers following consumption of heated corn oil.. Pak J Pharm Sci. 2017. PMID 29084680. (abstract)
- Hooper L, Al-Khudairy L, Abdelhamid AS, 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)
- Maki KC, Lawless AL, Kelley KM, et al.. Corn oil improves the plasma lipoprotein lipid profile compared with extra-virgin olive oil consumption in men and women with elevated cholesterol: results from a randomized controlled feeding trial.. J Clin Lipidol. 2015. PMID 25670360. DOI 10.1016/j.jacl.2014.10.006. (abstract)
- Maki KC, Lawless AL, Kelley KM, et al.. Corn oil intake favorably impacts lipoprotein cholesterol, apolipoprotein and lipoprotein particle levels compared with extra-virgin olive oil.. Eur J Clin Nutr. 2017. PMID 27677368. DOI 10.1038/ejcn.2016.169. (abstract)
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- . FDA: Questions and Answers Regarding Food Allergens, Including the Food Allergen Labeling Requirements (Edition 5), guidance for industry. . . (excerpt)
- . FDA: Food Allergies. . . (full-text)
- . FDA: Qualified Health Claims, Letter of Enforcement Discretion, Corn Oil and Corn Oil-Containing Products and a Reduced Risk of Heart Disease (Docket 2006P-0243), 26 March 2007. . . (full-text)
- . FDA: Trans Fat. . . (excerpt)
- . GBIF Backbone Taxonomy: species match for Zea mays. . . (full-text)
- . MedlinePlus: Vitamin E in diet. . . (full-text)
- . NHS: Different fats in our diet (fat: the facts). . . (full-text)
- . USDA FoodData Central: Oil, corn, industrial and retail, all purpose salad or cooking (FDC 171029, SR Legacy). . . (summary-only)
Where to buy
Check the label first. Whatever you buy, look for these:
- Cold-pressed or refined, to match how you cook
- A harvest or best-by date and a dark glass or tin container
- The oil's origin and any testing statement
- Smoke point for the way you cook
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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