Unsolved:Seed oil misinformation

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Short description: Medical controversy

Flax, flax seeds, linseed oil, and linseed cake

Since 2018, the health effects of consuming certain processed vegetable oils, or seed oils have been subject to misinformation in popular and social media. The trend grew in 2020 after podcaster and comedian Joe Rogan interviewed fad diet proponent Paul Saladino about the carnivore diet. Saladino made several claims about the health effects of vegetable fats.[1]

The theme of the misinformation is that seed oils are the root cause of most diseases of affluence, including heart disease,[2] cancer,[3] diabetes,[4] and liver spots.[5] These claims are not based on evidence,[6] but have nevertheless become popular on the political right.[7] Critics cite a specific "hateful eight" oils that constitute "seed oils": canola, corn, cottonseed, soybean, sunflower, safflower, grapeseed, and rice bran.[8]

Seed oils emerged in the early 20th century through industrial extraction methods, including solvent use like hexane, which is safe in trace amounts. Although critics raise concerns about processing, omega-6 fatty acids, and linoleic acid, scientific evidence finds these oils safe and beneficial, with omega-6s linked to lower cardiovascular risk and no consistent evidence of increased inflammation, cancer, or chronic disease. Claims that seed oils are harmful are not supported by clinical or epidemiological data, and some health organizations warn that reducing omega-6 intake could worsen heart health.

Consumer vegetable oils are generally recognized as safe for human consumption by the United States FDA.[9]

Origins and scientific evaluation

Cover of the original Crisco cookbook, 1912

Seed oils are oils extracted from the seed, rather than the pulp or fruit, of a plant. Seed oils are characterized by the industrial process used to extract the oil from the seed and a high content of polyunsaturated fatty acids (PUFAs).[10] Critics' "hateful eight" oils consist of canola, corn, cottonseed, soy, sunflower, safflower, grapeseed, and rice bran oils,[8] which are creations of industrialization in the early twentieth century. In the United States, cottonseed oil was developed and marketed by Procter & Gamble as the creamed shortening Crisco in 1911.[11] The extracted oil was refined and partially hydrogenated to give a solid at room temperature and thus mimic natural lard, and canned under nitrogen gas.

Industrial solvents

Critics of seed oils often point to the health hazards of the solvents used in the industrial process of generating vegetable oils.[12] Hexane, which can be neurotoxic, is extremely effective at oil extraction.[13] Thus, it is often quoted as a danger when consuming vegetable oils as it can be found in finished oils in trace amounts.[14] The United States Environmental Protection Agency studied the toxicity of hexane extensively in the 1980s.[15] The studies found that the hexane used in industrial processes was safe for consumption and did not cause nerve damage.[16]

Omega-6 fatty acids

A comparison of the composition of different types of vegetable oils and animal fats. Oils from seeds have the lowest percentage of saturated fat, and range widely in their composition of omega-3, omega-6, and omega-9.

Sunflower, corn, and soybean oil have a higher proportion of omega-6 fatty acids than oils from fish, walnuts, flaxseed, and rapeseed (canola). Omega-6 fatty acids constitute a growing proportion of Americans' fat intake. They have been hypothesized to contribute to several negative health effects, including inflammation[17] and immunodeficiency,[18] but most cardiovascular health researchers believe the data shows that omega-6 fatty acids are safe and healthy for humans.[19] In fact, omega-6 fatty acids are significantly associated with a lowered risk of cardiovascular disease,Template:Sfnpm and the American Heart Association has stated that a reduction in omega-6 fatty acids could lead to an increase, not reduction, in cardiovascular disease.[20] Research indicates that consumption of omega-6 fatty acids has no significant effect on inflammatory bowel disease.[21]

Linoleic acid

Opponents of seed oils have argued that linoleic acid, an essential fatty acid found in seed oils such as safflower oil and sunflower oil increases chronic disease risk such as cardiovascular disease, cancer and systemic inflammation.[22] This idea is not supported by data from recent clinical trials or long-term epidemiological studies.[23] It has been shown that higher in vivo circulating and tissue levels of linoleic acid are associated with lower risk of major cardiovascular events.[24] A 2025 review of human outcome data concluded that linoleic acid from seed oils does not increase chronic disease risk. The review also noted that the human research evidence shows that linoleic acid intake does not affect inflammation or increase inflammatory biomarkers.[25]

The World Cancer Research Fund and Cancer Council Australia have stated that there is no scientific evidence that consuming seed oils increases cancer risk.[26][27]

Omega-6:omega-3 ratio

A 2024 review stated that dietary recommendations should not be made based on the omega-6:omega-3 ratio, but rather on their absolute dietary intake levels.[28] The omega-6:omega-3 ratio is calculated by accounting for all of the omega-6 fatty acids in the diet or blood divided by the sum of all omega-3 fatty acids.[28] Concern about a high omega-6:omega-3 ratio was based on the competition between linoleic acid and alpha-linolenic acid for desaturation enzymes, and because metabolites of omega-6 fatty acids were considered to be pro-inflammatory.[28]

Increased consumption of omega-6 fats has been linked to higher rates of obesity, insulin resistance, hypertension, and coronary heart disease.[29] Evidence indicates that replacing dietary omega-6 fatty acids with plant and marine omega-3s may reduce the risk of cardiovascular disease and certain cancers due to the potential for omega-6 levels to inhibit the body's ability to synthesize and utilize omega-3s.[30] Consuming high amounts of omega-6 fatty acids may compromise cardiovascular health by displacing essential omega-3s as the two compete for the same enzymatic pathways, meaning excess omega-6 can directly interfere with omega-3 metabolism.[31] Maintaining a balanced dietary omega-6 to omega-3 ratio between 1:1 and 4:1 may optimally reduce inflammation and mitigate the risk of chronic conditions, including cardiovascular and neurodegenerative diseases.[32]

A balanced 1:1 omega-6 to omega-3 ratio is also correlated with the integrity and function of male sperm. Consequently, the highly skewed ratios typical of modern Western diets are heavily associated with impaired semen quality and increased rates of male infertility.[33] Animal models support these broader findings, demonstrating that a 1:1 ratio effectively decreases systemic and vascular inflammation in mice.[34]

However, there is insufficient evidence in humans that omega-6 fats are pro-inflammatory and that omega-3 fats are anti-inflammatory.[28] In contrast, higher omega-6 levels are associated with lower inflammatory status, indicating that intake of omega-6 fats is not a dietary concern, and that relatively low intake of dietary omega-3 fats may lead to inflammation.[28] Accordingly, use of the omega-6:omega-3 ratio has been rejected as an inflammation biomarker by health agencies worldwide.[28] Numerous health and scientific organizations recommend intake of omega-6 seed oils as part of a healthy diet to replace sources of saturated fats, such as in palm and coconut oils, butter, tallow, and lard.[28]

Political connotations

Opposition to seed oils has been associated with the political right. Maya Vinokour, an assistant professor at NYU, writing for Jacobin, described the belief as "lifestyle fascism" and "right-wing masculinist discourse".[7]

Robert F. Kennedy Jr., United States Secretary of Health and Human Services since 2025, has expressed opposition to seed oils. In the 2024 U.S. presidential election, Kennedy ran as an independent candidate and campaigned on health-related misinformation.[35] In his speech suspending his campaign and endorsing that of Donald Trump, he blamed several health conditions on processed foods' inclusion of seed oils.[36] Later that day, Kennedy appeared alongside Trump to declare that the latter would "Make America Healthy Again," endorsing Trump's health and food policies.[37]

US vice president JD Vance has also stated that he does not cook with seed oils.[38]

In response to the growing political opposition from the Trump administration's MAHA movement, agricultural trade groups and industry lobbyists have begun campaigning to defend the safety of seed oils to lawmakers and food corporations. [39]

References

  1. ↑
    • Zaleski (2021): "Last year, Joe Rogan talked to doctor and carnivore diet evangelist Paul Saladino about this for more than three hours."
    • Williams (2022): "[T]he interview with Saladino resonated with Rogan's curious, hungry, and enormous audience"
    • Carleton (2022): "Take Dr. Paul Saladino, the doctor behind the Carnivore Diet, which recommends replacing plant foods with meat, for example—he spent three hours on the Joe Rogan Experience in 2020 describing the harms of seed oils, among other fringe views, including that doing cold plunges has the same health benefits as consuming a plate of vegetables. His name is often mentioned on this section of the internet, (one redditor attributed the proliferation of anti-seed oil sentiment entirely to his appearance on the podcast)."
    • Saladino (2020), 58:23: "I think it's important to understand what we talked about, processed vegetable oils and processed sugars, hugely bad for humans."
  2. ↑ Harvard University (2022): "[P]ushed back on the idea that these oils cause health ills ranging from headaches to heart disease."
  3. ↑ Bailey (2023): "the bulk of recent research has not been kind to Simopoulos' assertion that the supposedly imbalanced consumption of linoleic acid found in seed oils 'makes you more vulnerable to heart disease, cancer, obesity, inflammations, autoimmune diseases, allergies, diabetes and depression.'"
  4. ↑ Liao (2022): "[T]hey're blamed for a host of ills, such as headaches, foggy thinking, lowered immunity, heart disease, type 2 diabetes, and more."
  5. ↑ Williams (2022): "[I]f you want something to blame for everything from cancer to heart disease, dementia to age spots, there are a whole lot of people out there who will tell you the culprit is lurking in your pantry"
  6. ↑
    "Scientists debunk claims of seed oil health risks" (in en-us). 2022-06-22. https://www.hsph.harvard.edu/news/hsph-in-the-news/scientists-debunk-seed-oil-health-risks/. "There's no reason to avoid seed oils and plenty of reasons to eat them" (in en). https://www.heart.org/en/news/2024/08/20/theres-no-reason-to-avoid-seed-oils-and-plenty-of-reasons-to-eat-them. 
  7. ↑ 7.0 7.1 Vinokour (2024): "Without ever calling themselves Übermenschen or decrying modern ways of living as 'degenerate,' the Johnsons slot their intention to recover a lost golden age (Brian) or attain futuristic utopia (Bryan) among myriad online wellness trends. Against this background, their contributions to right-wing masculinist discourse seem almost incidental. It is true that Liver King proscribes the consumption of seed oils as one of his 'ancestral tenets,' and that programmatic opposition to seed oils correlates with conspiratorial right-wing thinking."
  8. ↑ 8.0 8.1
    • Zaleski (2021): "On another podcast in 2020, board-certified family physician Cate Shanahan referred to the most common seed oils on the market today as the 'hateful eight,' to be avoided at all costs."
    • Bailey (2023): "The prime sources of linoleic acid in modern diets are seed oils including soybean, corn, cottonseed, sunflower, canola, safflower, rice bran, and grapeseed oils. The use of these oils has increased in modern diets, and they have been dubbed by some self-proclaimed health and wellness gurus as the 'hateful eight.'"
  9. ↑
    • Harvard University (2022): "'Cooking with seed oils at home isn’t an issue.'"
    • Lusas et al. (2017), p. 902: "Canola oil, which contains less than 2% erucic acid compared with 20–40% in earlier rapeseeds, was granted GRAS (generally recognized as safe) status by the US-FDA in 1985"
    • Eskin et al. (2020), p. 5: "In 1985, canola received Generally Recognized as Safe (GRAS) status in the United States"
  10. ↑
    • La Pera et al. (2010)
    • Sharmila et al. (2020), p. 174: "Seed oil is a form of vegetable oil mainly extracted from seeds of various fruits and vegetables."
    • Gaber et al. (2023): "Seed oils are extracted from the seed (endosperm) of some plants such as canola, sunflower, and soybeans. This is commonly achieved through industrial processing of thermally conditioned flaked seeds using expellers to extract the oil mechanically."
  11. ↑ Ramsey & Graham (2012): "Soon the company's scientists produced a new creamy, pearly white substance out of cottonseed oil. It looked a lot like the most popular cooking fat of the day: lard. Before long, Procter & Gamble sold this new substance (known today as hydrogenated vegetable oil) to home cooks as a replacement for animal fats."
  12. ↑ Dennett (2023), p. 18: "Another criticism is that seed oil manufacturers use heat and solvents, such as hexane, to extract oil from seeds, creating unhealthful trans fats and chemical contaminants."
  13. ↑ Wakelyn & Wan (2003), p. 365: "Direct solvent extraction involves the use of a nonpolar solvent, usually commercial hexane, to dissolve the oil from oilseed flakes or collets without removing proteins and other non-oil-soluble compounds. Solvent extraction yields about 11.5% more oil than does the screw press method, and less oil remains in the meal."
  14. ↑ Cravotto et al. (2022), p. 18: "Some studies have been conducted on n-hexane residues in commercial products showing the presence of n-hexane in commercial hexane-extracted oils, in food products, and in functional health foods"
  15. ↑ Environmental Protection Agency (1988), p. 3382: "Pursuant to section 4(a) of the Toxic Substances Control Act (TSCA), EPA is issuing a final test rule requiring manufacturers and processors of commercial hexane to perform testing for subchronic toxicity, oncogenicity, reproductive toxicity, developmental toxicity, mutagencity, neurotoxicity, and inhalation and dermal pharmacokinetics."
  16. ↑
    • Wakelyn & Wan (2003), p. 366: "[C]ommercial hexane, which contains 52% n-hexane and a mixture of hexane isomers (see composition below), does not cause peripheral nerve damage in animals."
    • Galvin (1997), p. 83: "The sum total of this mandated testing program indicates that C. hexane is a relatively safe chemical. It is not a neurotoxicant (as is pure n-hexane). It does not cause cancer in rodents in a mechanism relevant to humans as demonstrated by these studies. Commercial hexane has gone through an extensive EPA-mandated testing program. All the tests to date have shown C. hexane to be rather innocuous."
  17. ↑ Ball & Burch (2024): "While all oils contain varying levels of fatty acids, some argue an excessive intake of a specific omega-6 fatty acid in seed oils called 'linoleic acid' may contribute to inflammation in the body."
  18. ↑
    • Myles (2014), p. 4: "Thus, another potential contributor to modern diet-induced immune dysfunction may be the increased consumption of omega-6 in lieu of omega-3 fatty acids."
    • Harvard University (2019): "The critics argue that we should cut back on our intake of omega-6 fats to improve the ratio of omega-3 to omega-6s."
  19. ↑ Harvard University (2019): "In a science advisory that was two years in the making, nine independent researchers from around the country, including three from Harvard, say that data from dozens of studies support the cardiovascular benefits of eating omega-6 fats."
  20. ↑
    • Harris et al. (2009), p. 904: "The data also suggest that higher intakes appear to be safe and may be even more beneficial (as part of a low–saturated-fat, low-cholesterol diet). In summary, the AHA supports an omega-6 PUFA intake of at least 5% to 10% of energy in the context of other AHA lifestyle and dietary recommendations. To reduce omega-6 PUFA intakes from their current levels would be more likely to increase than to decrease risk for CHD."
    • Petersen (2024): "Seed oils, especially safflower oil, sunflower oil, corn oil and soybean oil, are rich in a kind of unsaturated fat called omega-6. Scientific studies have found that when people swap out some of the saturated fats in their diets (from foods such as butter and red meat) and replace them with omega-6 fats, their levels of LDL cholesterol (the 'bad' cholesterol) lower. Their risk of heart attacks and death from cardiac events also drops."
  21. ↑ Ajabnoor et al. (2021); Dennett (2023), p. 18: "What antiseed oil influencers miss is that arachidonic acid also is a building block for compounds that fight inflammation. The inflammatory claims mostly are based on research in rodents, but mice and rats don’t respond to linoleic acid the same way humans do. In fact, human research has found that linoleic acid isn’t inflammatory overall."
  22. ↑ Lee & Keszya (2025)
  23. ↑ Lee & Keszya (2025)
  24. ↑ Marklund et al. (2019): "In pooled global analyses, higher in vivo circulating and tissue levels of LA and possibly AA were associated with lower risk of major cardiovascular events. These results support a favorable role for LA in CVD prevention."
  25. ↑ Lee & Keszya (2025) "The current human research evidence shows that linoleic acid does not affect inflammation."
  26. ↑ "Are seed oils good or bad for our health?" (in en-GB). 2025. https://www.wcrf.org/about-us/news-and-blogs/are-seed-oils-good-or-bad-for-our-health/. 
  27. ↑ "Can vegetable/seed oils cause cancer?" (in en-GB). 2021. https://www.cancer.org.au/iheard/can-vegetable-seed-oils-cause-cancer. 
  28. ↑ 28.0 28.1 28.2 28.3 28.4 28.5 28.6 "Perspective on the health effects of unsaturated fatty acids and commonly consumed plant oils high in unsaturated fat". The British Journal of Nutrition 132 (8): 1039–1050. October 2024. doi:10.1017/S0007114524002459. PMID 39475012. 
  29. ↑ Saini, Ramesh Kumar; Keum, Young-Soo (2018). "Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism, and significance — A review". Life Sciences 203: 255–267. doi:10.1016/j.lfs.2018.04.049. PMID 29715470. Simopoulos, Artemis P. (1994). "Is insulin resistance influenced by dietary linoleic acid and trans fatty acids?". Free Radical Biology and Medicine 17 (4): 367–372. doi:10.1016/0891-5849(94)90023-X. PMID 8001841. Simopoulos, Artemis P. (2002). "The importance of the ratio of omega-6/omega-3 essential fatty acids". Biomedicine & Pharmacotherapy 56 (8): 365–379. doi:10.1016/S0753-3322(02)00253-6. PMID 12442909. https://www.sciencedirect.com/science/article/pii/S0753332202002536. Retrieved 10 May 2026. Simopoulos, Artemis P. (2003). Omega-6/Omega-3 Essential Fatty Acid Ratio: The Scientific Evidence. S. Karger. ISBN 3-8055-7640-4. Strandvik, Birgitta (2011). "The omega-6/omega-3 ratio is of importance!". Prostaglandins, Leukotrienes and Essential Fatty Acids 85 (6): 405–406. doi:10.1016/j.plefa.2011.09.001. PMID 21945460. https://www.plefa.com/article/S0952-3278(11)00122-0/fulltext. Retrieved 10 May 2026. El-Badry, Ashraf Mohammad; Graf, Rolf; Clavien, Pierre-Alain (2007). "Omega 3 – Omega 6: What is right for the liver?". Journal of Hepatology 47 (5): 718–725. doi:10.1016/j.jhep.2007.08.005. PMID 17869370. 
  30. ↑ de Lorgeril, Michel; Salen, Patricia (2012). "New insights into the health effects of dietary saturated and omega-6 and omega-3 polyunsaturated fatty acids". BMC Medicine 10 (50). doi:10.1186/1741-7015-10-50. PMID 22613931. Bibcode: 2012BMCM...10...50D. 
  31. ↑ Farvid, Maryam S.; Ding, Ming (2014). "Dietary Linoleic Acid and Risk of Coronary Heart Disease: A Systematic Review and Meta-Analysis of Prospective Cohort Studies". Circulation 130 (18): 1568–1578. doi:10.1161/CIRCULATIONAHA.114.010236. PMID 25161045. Bibcode: 2014Circu.130.1568F. de Lorgeril, Michel; Salen, Patricia (2012). "New insights into the health effects of dietary saturated and omega-6 and omega-3 polyunsaturated fatty acids". BMC Medicine 10 (50). doi:10.1186/1741-7015-10-50. PMID 22613931. Bibcode: 2012BMCM...10...50D. Simopoulos, Artemis P. (2008). "The Importance of the Omega-6/Omega-3 Fatty Acid Ratio in Cardiovascular Disease and Other Chronic Diseases". Experimental Biology and Medicine 233 (6): 674–688. doi:10.3181/0711-MR-311. PMID 18408140. Innes, Jacqueline K.; Calder, Philip C. (2018). "Omega-6 fatty acids and inflammation". Prostaglandins, Leukotrienes and Essential Fatty Acids 132: 41–48. doi:10.1016/j.plefa.2018.03.004. PMID 29610056. Haque, M.; Rahman, M.; Alam, M.; Akter, S. (2017). "A Possible Approach for Maintaining Effective Omega-6/ Omega-3 Fatty Acid Ratio from Mixed Vegetable Oils". Journal of Environmental Science and Natural Resources 9 (2): 65–69. doi:10.3329/jesnr.v9i2.32159. Stoll, Andrew (2001). The Omega-3 Connection. New York: Simon and Schuster. p. 40. 
  32. ↑ Gutierres, D; Pacheco, R; Reis, CP (2025). "The Role of Omega-3 and Omega-6 Polyunsaturated Fatty Acid Supplementation in Human Health". Foods 14 (19): 3299. doi:10.3390/foods14193299. PMID 41097470. 
  33. ↑ Safarinejad, M. R.; Safarinejad, S. (2012). "The roles of omega-3 and omega-6 fatty acids in idiopathic male infertility". Asian Journal of Andrology 14 (4): 514–515. doi:10.1038/aja.2012.46. PMID 22659579. 
  34. ↑ DiNicolantonio, James J.; O'Keefe, James H. (2018). "Omega-6 vegetable oils as a driver of coronary heart disease: the oxidized linoleic acid hypothesis". Open Heart 5 (1). doi:10.1136/openhrt-2018-000898. PMID 30364556. Yehuda, S.; Carasso, R. L. (1993-11-01). "Modulation of learning, pain thresholds, and thermoregulation in the rat by preparations of free purified alpha-linolenic and linoleic acids: determination of the optimal omega 3-to-omega 6 ratio.". Proceedings of the National Academy of Sciences of the United States of America 90 (21): 10345–10349. doi:10.1073/pnas.90.21.10345. PMID 7901853. Bibcode: 1993PNAS...9010345Y. 
  35. ↑ Hitchens (2023): "His followers include a chunk of the podcast-loving, seed-oil-skeptical, raw-milk-drinking crowd."
  36. ↑ Eckstein (2024a): "Kennedy, who spent tens of minutes ranting about seed oils, estrogen and pharmaceutical companies, also promoted in his speech the same conspiracy theories against vaccines that he's lobbed for years."
  37. ↑ Eckstein (2024b): "'Don't you want a president that's going to make America healthy again?' the famously vaccine-skeptic Kennedy asked, hours after blaming seed oils and processed foods for America's position during the Trump administration as a world leader in COVID deaths."
  38. ↑ Breland (2024): "Vance says that he doesn't cook with seed oils, a cause du jour of the online right"
  39. ↑ McNamara, Sylvie (August 4, 2025). "It’s a Weird Time to Be a Seed Oil Lobbyist". Washingtonian. https://washingtonian.com/2025/08/04/its-a-weird-time-to-be-a-seed-oil-lobbyist/. 

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