A shadowy corner of the Internet would have you believe that common kitchen staples you probably have in your pantry right now are poison. Social media personalities have waged war against the so-called “Hateful Eight”: canola, corn, cottonseed, grapeseed, soy, rice bran, sunflower, and safflower. According to certain TikTok-ers and podcasters, the oils extracted from these plants are toxic, inflammatory, and entirely to blame for serious health issues sweeping North America — from obesity to diabetes, heart disease, and stroke. No one is more baffled by these claims than scientists, nutritionists, and doctors. Below, we pit fact against fiction, breaking down the scientific evidence experts want you to know in the face of all the myths and misinformation proliferating online right now.
“It’s so odd that the internet has gone wild demonizing these things. They are not to be feared.” — Dr. Christopher Gardner, professor of medicine at Stanford University School of Medicine and nutrition scientist at the Stanford Prevention Research Center
What Are Seed Oils?
Also known as vegetable oil, seed oils are plant-based oils that have been used for cooking and baking in kitchens around the world for decades. They first came on the scene as an alternative to partially hydrogenated oils — a hefty source of trans fat. Starting around the 1950s, research started to uncover a link between these trans fats and increases in “bad” cholesterol levels. Today, partially hydrogenated oils and trans fats are widely known to cause heart disease and increase people’s risk of heart attacks. Seed oils were developed as a heart-healthy alternative. As their name suggests, seed oil is extracted from plants’ seeds, as opposed to their fruit. Some examples of seed oils include:
- Canola (rapeseed) oil
- Sunflower oil
- Safflower oil
- Soybean oil
- Corn oil
- Cottonseed oil
- Grapeseed oil
To ensure delicious taste, cost-efficiency, and longer shelf life, many seed oils undergo a refining process — which brings us to the first false allegation waged against seed oils in the social media debate.
Seed Oil Myths vs Truths
Myth#1: Are seed Oils Toxic?
Critics claim this production process makes seed oils “unnatural,” full of toxic additives. But experts emphasize it’s precisely what makes the oils safe. “The processing actually takes out potentially toxic material,” explains Tom Sanders, emeritus professor of nutrition and dietetics at King’s College London. These impurities could impact seed oils’ taste, or cause them to spoil. The refining process helps keep seed oils fresh and shelf stable. Others point the finger at the “linoleic acid” in seed oils, which detractors say breaks down into unhealthy toxins when heated. Dr. Gardner explains that seed oils are indeed rich with linoleic acid, a type of omega-6 fatty acid. Where critics go wrong is in their claims that these acids are somehow “bad.” Omega-6 is a polyunsaturated fatty acid: a “good fat” that provides many health benefits, including reducing “bad” cholesterol and, in turn, risk of heart disease and stroke. In fact, the American Heart Association lists omega-6 fatty acids as part of a healthy diet.
Expert Insight
“The idea that linoleic acid is some sort of toxic thing is absolute nonsense. It’s an essential nutrient. Of the essential fatty acids, it’s the most important one. If you’re deficient, it impairs immune function and platelet function doesn’t work.” — Tom Sanders, emeritus professor of nutrition and dietetics at King’s College London.
Myth#2: Are Seed Oils Inflammatory?
Linoleic acid is also at the heart of a second myth about seed oils, which is that they are “inflammatory” and, as a result, causes chronic illness. Science says otherwise. Sarah Berry, professor of nutritional sciences at King’s College London, explains that this myth hinges on a misunderstanding of the difference between omega-6 and omega-3. Like the omega-6 found in linoleic acid, omega-3 is also an essential polyunsaturated fatty acid. Omega-3 is found in foods like fish, chia seeds, and flaxseed and is widely praised for being “anti-inflammatory” and health-promoting. “The enzymes used to convert omega-3 into anti-inflammatory chemicals are the same ones used to convert omega-6,” Berry notes. This seems to concern seed oil critics: “Their argument is that having too much seed oil will mean the enzymes are stolen away from the omega-3. This isn’t true.” Instead, Berry and countless other experts say a balance is best. “Scientists who study omega-6 and omega-3 think we need both,” says Martha Belury, an Ohio State University food science professor who has studied fatty acids for three decades. “Seed oils do not increase acute or chronic inflammation markers.” Dr. Gardner from Stanford agrees. “Both omega-6 and omega-3 fats play a role in the inflammatory response of the body,” he says. “What is optimal is a balance.”
Myth#3: Do Seed Oils Cause Obesity and Heart Disease?
Whether they reference the toxicity myth or misinformation on inflammation, most people are wondering if seed oils are unhealthy — responsible for the obesity and heart health epidemics. Ironically, science says the opposite: seed oils lower bad cholesterol, reduce inflammation, and offer a heart-healthy alternative to trans fats. Remember, seed oils emerged in the first place because research revealed the dire health consequences of consuming trans-fat-laden partially hydrogenated oils. These saturated fats can raise cholesterol levels and increase people’s risk for heart disease and stroke. Over the past 50 years, cardiovascular disease has been on the decline — and scientists say we have seed oils to thank. “It has been shown to reduce blood cholesterol significantly,” reports Berry. “I would say that not only are seed oils not bad for us, they are a healthy part of our diet.” For example, one study published in Journal of the American Medical Association (JAMA) found that people who consumed 2.5 to three teaspoons of butter every day increased their risk of death by 15 per cent. On the other hand, those who replaced butter with the same amount of plant-based oil saw a 17% reduction in risk of death. Another study found that people who consumed more linoleic acid had lower levels of glucose, insulin, and inflammation. These are all risk factors for type 2 diabetes and heart disease. In other words, this study showed that higher consumption of linoleic acid is associated with a lower risk of diabetes, heart attack, and stroke.
Expert Insight
“Despite growing concern by the public that seed oils are health-harming, this study adds to the already sizable body of research that says this is just not true. I hope that this study and others like it quash some of the fears that people have about seed oils. “If I thought [canola oil] was harmful, I wouldn’t be [cooking with] it myself.” — Nate Wood, Yale Medicine obesity and internal medicine physician
Myth#4: Aren’t Chronic Diseases Rising Alongside Seed Oil Consumption?
Seed oil consumption has increased exponentially over the last several decades. Rates of concerning health issues, from obesity to diabetes, have also risen over a similar timeframe — causing critics to speculate that seed oils are to blame. But as Berry explains: “Association does not mean causality. Think what else has changed; our food landscape is almost unrecognisable compared with 70 years ago. It’s estimated 60% of the seed oils we consume come from ultra-processed food which has many other chemicals that are unhealthy for us and processes that affect the healthfulness of the food.” In other words: it’s not the seed oils themselves that are the problem here. Abby Langer, a registered dietitian in Toronto, says over-consuming ultra-processed foods can cause rapid weight gain and ultimately lead to other health issues. Often, these negative health consequences stem from harmful ingredients in these foods, like high-fructose corn syrup, added sugars, and sodium. Dr. Gardner agrees: “It’s hard to cast the blame on the seed oils when these foods contain so many other things.”
Expert Insight
“We do know that diets high in processed foods are linked to poorer health outcomes. The seed oil is not the likely driver for negative health effects. These processed foods also tend to have higher levels of refined carbohydrates, salt and sugar, which are all things we know in excess can impact health negatively.” — Jason S. Ewoldt, M.S., RDN, wellness dietitian at Mayo Clinic
How Did We Get Here?
The science on seed oils is very clear. Decades of research shows that seed oils are safe, non-toxic, and can in fact reduce your risk for various health concerns. Given the overwhelming amount of evidence in favour of seed oils, you might be wondering: how did these pantry staples become so vilified? Qualified experts are equally exasperated by the baseless speculation they see online. For social media influencers, more dramatized, outrageous claims typically mean more attention and engagement. Some therefore reduce complex science to oversimplified soundbites.
“The seed oil scare is all just gossip. It’s not based on any good science at all. Human nature is such that we are more susceptible to risk and scare headlines. They’re going to get more clicks than a balanced, boring nutrition scientist like myself saying seed oils are fine as part of a balanced diet.” — Sarah Berry, professor of nutritional sciences at King’s College London
In short, not all “influencers” are qualified to offer nutrition or health guidance. Instead, let’s hear from the experts who are.
Seed Oils: Part of Your Healthy, Balanced Diet
Doctors, scientists, and nutritionists emphasize that seed oils can be a valuable inclusion in your healthy, well-rounded diet for many reasons:
1. Heart Health
As mentioned, seed oils can lower “bad” cholesterol, reducing risk for challenges such as heart attacks. Studies show that using seed oils in place of butter is an easy way to protect your cardiovascular health. Public health organizations, including the American Heart Association, recommend this switch.
2. The “Gateway Ingredient” Effect
With their high smoke points and varied flavours, seed oils are suitable for a diverse range of cooking needs — from sautéing to salad dressings. Experts say they can therefore serve as “gateway ingredients,” opening the door to even more nutritious food choices. To illustrate the concept, Dr. Gardner says he would use sesame oil when making a vegetable stir-fry. “And if it means that, because you did that, you’re going to have the veggie stir-fry and the salad and you’re going to eat more of it because of the flavor? Fantastic.”
“The seed oils are not killing you. They are helping you enjoy more healthy foods.” — Dr. Christopher Gardner, professor of medicine at Stanford University School of Medicine and nutrition scientist at the Stanford Prevention Research Center
The Bottom Line: What Should You Eat?
At the end of the day, it’s up to each of us to believe in science over soundbites. And the science couldn’t be clearer: seed oils are not only perfectly safe, but a valuable addition to your diet. Qualified experts emphasize the bigger picture. If you’re aiming to eat well and take care of your health, focus on:
- Enjoying more home-cooked meals, as opposed to eating out
- Opting for more whole foods over ultra-processed ones
- Incorporating a variety of vegetables, lean protein, whole grains, and healthy fats into each meal
And if seed oils help you achieve these goals? Then they’ve earned their place in your pantry.
References and Further Reading:
- Dietary Linoleic Acid and Risk of Coronary Heart Disease
- Kennedy and Influencers Bash Seed Oils, Baffling Nutrition Scientists
- Replacing Butter by Some Plant Oils Could Significantly Lower Risk of Mortality, New Study Finds
- RFK Jr Says They Are Poisoning Us, Influencers Call Them Unnatural – But What is the Truth About Seed Oils?
- Robert F. Kennedy Jr. Says Beef Tallow is Healthier Than Seed Oils. Is He Right?
- Social Media Suggests Seed Oils — Like Canola — Are Bad For You. More Science is Saying Otherwise
- The Pros and Cons of Seed Oils, and How to Incorporate Them in Your Diet
- There’s No Reason to Avoid Seed Oils and Plenty of Reasons to Eat Them
- Worried About Seed Oils? Studies Say Linoleic Acid May Actually Lower Disease Risk