Seed oils are the latest villain in the wellness world, with social media influencers blaming them for everything from headaches to heart disease.
The online buzz has gotten so loud, it’s now echoing in the halls of Congress, where Robert F. Kennedy Jr. has railed against seed oils in his bid for Health and Human Services secretary.
While the conversation seems to be reaching a fever pitch online, the debate over seed oils’ health impact has been simmering for decades. The Post spoke with three registered dietitians and nutritionists to find out if they’re really as harmful as the hype suggests — and what you should be eating instead.
Are seed oils unhealthy?
Seed oils — refined cooking oils extracted from the seeds of various plants — are often labeled as “toxic” by critics. First introduced in the early 1900s as a cheaper alternative to animal fats, they are now a staple of the American diet.
The oils most often singled out in the controversy are the so-called “Hateful Eight”: canola, corn, cottonseed, grapeseed, soy, sunflower, safflower and rice bran.
Kennedy and others say that Americans are being “unknowingly poisoned” by these oils, even going so far as to argue that cooking with beef fat is a healthier option. But nutrition experts are pushing back on that claim, with several saying their impact is a bit more complicated.
“Seed oils in and of themselves are not unhealthy,” Maya Feller, a registered dietician and nutritionist, told The Post. “They are a source of monounsaturated and polyunsaturated fatty acids and contain both omega 6 fatty acids as well as omega 3 fatty acids to varying degrees.”
Part of the problem, experts argue, lies in how these oils are processed.
“Many seed oils are refined using high heat and chemical processing, which can lead to oxidation that forms harmful compounds that may increase disease risk,” said Amy Shapiro, a registered dietician and nutritionist.
What’s the deal with omega-6?
One of the biggest concerns surrounding seed oils is their high levels of omega-6 fatty acids, especially in comparison to their lower amounts of omega-3s.
Both omega-6s and omega-3s are polyunsaturated fats. They’re essential for the body, but you can’t produce them on your own, so you need to get them through food.
Throughout human evolution, the ratio of omega-6s to omega-3s that people consumed varied between populations but was generally estimated to be about 1:1. However, in the past century, that balance has shifted dramatically in the Western diet, with some estimates putting it as high as 20:1.
“The problem seems to be in the proportions of the two fats that we take in,” said Stephanie Schiff, a registered dietitian nutritionist at Northwell Huntington Hospital. “We tend to get a higher than healthy ratio of omega-6s to omega-3s and that can lead to problems with inflammation in the body.”
Chronic inflammation is thought to be at the root of many health problems, including arthritis, heart disease and type 2 diabetes. Regulating junk food and stemming the tide of chronic disease in the US is a top priority for the Trump administration, which has tasked Kennedy with carrying out the president’s vision.
Critics of seed oils argue that we should cut back on omega-6s to reduce inflammation and other health ills. But the research isn’t so clear cut.
For example, a 2017 review of randomized control trials found that people who consume more omega-6 fatty acids generally don’t have higher markers of inflammation in their blood. Instead, they may be healthier.
There’s also growing evidence suggesting that a higher intake of omega-6 fatty acids could benefit cardiovascular health and reduce the risk of stroke. The American Heart Association supports including omega-6s in a balanced diet as part of an overall strategy to prevent heart disease.
Other research suggests that when people swap seed oils high in unsaturated fats — like sunflower, safflower and rapeseed — for saturated fats such as butter and lard, it can lower LDL cholesterol (often referred to as the “bad” cholesterol) and overall cholesterol levels.
Seed oils in ultra-processed foods
But it’s not just the oils themselves. How they’re used in our food system is also a big part of their bad rap.
Seed oils are abundant in packaged and ultra-processed foods, which have become a staple in the American diet due to their affordability, accessibility and long shelf life, according to Feller.
“Many processed foods also supply an overabundance of added sugars, saturated and synthetic fats, and added salts, all of which have been linked to increased development as well as the worsening of chronic illnesses like cardiovascular disease and diabetes,” she said.
Shapiro echoed that idea, stressing that ultra-processed foods just generally make for a “nutrient-poor diet.”
Should I avoid seed oils?
Schiff, Feller and Shapiro all agree: You don’t need to completely avoid seed oils, but like anything, they should be used in moderation. They stress the real issue is cutting back on highly processed foods.
“Highly processed foods are already unhealthy because they’re often high in sugar, saturated fat, salt and chemicals. You’re better off limiting them,” said Schiff.
“Try to choose foods as close to their natural state as possible. Mostly plant-based foods, they’re high in antioxidants, vitamins, minerals and fiber. If you prioritize this type of food, you should be able to use some seed oils in your diet.”
When cooking at home, Schiff and Shapiro both advise swapping refined seed oils for healthier fats like extra virgin olive oil or avocado oil.
To balance your omega-6 to omega-3 intake, Shapiro suggests adding more fatty fish, flaxseeds, chia seeds and walnuts to your diet.
The final verdict
“Simply saying the seed oils in packaged goods is the cause of the chronic illness epidemic in the United States is an oversimplification,” said Feller.
“Seed oils are spread throughout our food supply, making them hard to avoid. People who have access to a variety of options and have the financial flexibility will have an easier time omitting seeds oils from their patterns of eating, should they so choose.
“Generally, I recommend that people take an additive approach and actively add more vegetables, beans, nuts, seeds, ancient grains and lean proteins — both animal and plant.”