Harvard, Johns Hopkins and Stanford experts debunk viral claims that canola, sunflower and soy oils cause inflammation – as RFK Jr joins anti-seed oil crusade
Social media is awash with warnings that common cooking oils like canola and sunflower are “toxic” and causing everything from acne to cancer – but leading nutrition scientists say these viral claims are simply not backed by evidence.
Despite influencers dubbing them the “Hateful Eight” and blaming seed oils for the obesity epidemic, experts from Harvard, Johns Hopkins and Stanford are pushing back, saying the real problem isn’t the oils themselves but the ultra-processed foods they’re often found in.
“There is abundant evidence suggesting that seed oils are not bad for you. If anything, they are good for you,” says Dr Matti Marklund, assistant professor at Johns Hopkins Bloomberg School of Public Health.
What Are Seed Oils?
The so-called “Hateful Eight” that wellness influencers warn against are:
- Canola oil
- Corn oil
- Soybean oil
- Cottonseed oil
- Grapeseed oil
- Sunflower oil
- Safflower oil
- Rice bran oil
These oils are extracted from plant seeds through either mechanical pressing or chemical extraction, and have become ubiquitous in everything from salad dressings to potato chips since emerging as alternatives to partially hydrogenated oils in the late 1900s.
The ‘Toxic’ Claims vs The Science
CLAIM: Seed oils cause inflammation due to high omega-6 content
REALITY: “Seed oils do not cause inflammation,” according to Johns Hopkins nutrition scientists. A 2017 meta-analysis found that increased dietary intake of linoleic acid (the main omega-6 in seed oils) does not significantly affect inflammatory markers.
CLAIM: The omega-6 to omega-3 ratio in modern diets is dangerous
REALITY: While it’s true Americans consume about 15 times more omega-6s than omega-3s (compared to a 1:1 ratio historically), Stanford’s Dr Christopher Gardner says: “To flip that and suggest this means omega-6 fats are pro-inflammatory is wrong. Both omega-6 and omega-3 fats play a role in the inflammatory response of the body.”
CLAIM: Seed oils are processed with toxic chemicals
REALITY: While hexane is used in some extraction processes, the EPA has extensively studied its safety and found that trace amounts in finished oils are safe for consumption and do not cause nerve damage.
What Top Experts Really Say
Harvard T.H. Chan School of Public Health: “While it’s true that many foods that use seed oils—such as packaged snacks and french fries—are unhealthy, they also tend to be high in refined carbohydrates, sodium, and sugar… these other components, not the seed oils themselves, are the culprit.”
American Heart Association: The AHA supports including omega-6 fatty acids as part of a healthy diet, noting that polyunsaturated fats help reduce bad cholesterol and lower risk for heart disease and stroke.
Cleveland Clinic: Registered dietitian Julia Zumpano notes that while chronic inflammation is linked to various conditions, “this doesn’t mean seed oils cause chronic conditions, per se.”
The Real Culprit: Ultra-Processed Foods
Stanford’s Dr Gardner, who has studied dietary fats for over 30 years, points out a crucial distinction:
“I’ve gone back to some of the social influencer podcasts… what I typically hear is, seed oil consumption has doubled. And in the same time it’s doubled, obesity rates have risen, inflammation has risen… This is an association, not causation.”
The key issue? More than half of calories US adults consume come from ultra-processed foods, which happen to contain seed oils along with:
- High amounts of sugar
- Excessive sodium
- Artificial additives
- Refined carbohydrates
“That’s why it’s bad for you, not the inclusion of seed oils,” says Johns Hopkins’ Dr Marklund.
Surprising Health Benefits
Multiple large studies have actually found benefits to consuming unsaturated fats from seed oils:
- Lower LDL (bad) cholesterol compared to saturated fats
- Reduced risk of cardiovascular disease
- Lower rates of heart attack and stroke
- Better blood sugar regulation
“Every study for decades has shown that when you eat unsaturated fats instead of saturated fats, this lowers the level of LDL cholesterol in your blood,” says Stanford’s Gardner. “There are actually few associations in nutrition that have this much evidence behind them.”
One Exception: Migraines
While seed oils aren’t generally harmful, PBS reports on one rigorous study showing migraine sufferers who reduced omega-6 intake while increasing omega-3s experienced four fewer migraines per month – more effective than current medications.
The Political Connection
Opposition to seed oils has become associated with the political right, with Robert F. Kennedy Jr., the US Secretary of Health and Human Services, expressing opposition to them despite the scientific evidence.
Wikipedia notes that since 2018, seed oil misinformation grew particularly after podcaster Joe Rogan interviewed carnivore diet proponent Paul Saladino in 2020.
The Omega Balance
While experts agree omega-3s are important for health, they stress this doesn’t make omega-6s harmful:
Omega-3s are so important for overall health that we really need to make the effort to get them into our diets,” says Cleveland Clinic’s Zumpano. “Omega-6s, on the other hand, are already in abundance in Western diets.”
The solution? Add more omega-3 rich foods like:
- Fatty fish (salmon, sardines)
- Walnuts
- Flaxseeds
- Chia seeds
Bottom Line: Focus on Real Problems
To think that seed oils are anywhere near the top of the list of major nutrition concerns in our country is just nuts,” says Stanford’s Gardner.
Instead of avoiding seed oils, experts recommend:
- Eating fewer ultra-processed foods
- Increasing fruits and vegetables
- Choosing whole foods over packaged ones
- Using any plant oil over animal fats for cooking
As Johns Hopkins’ Marklund puts it: “Consider eating less ultra-processed food and more whole foods, fruit, and vegetables—and then use seed oils together with those.”
The Verdict
Despite viral TikTok videos and celebrity warnings, the scientific consensus is clear: seed oils are not toxic. The real health threat comes from the ultra-processed foods they’re often found in – not the oils themselves.
So next time you see a social media post warning about the “dangers” of canola oil, remember what the actual scientists say: these common cooking oils are perfectly safe and may even be good for you when used as part of a balanced diet.
