Are Seed Oils Really That Bad for Your Health?
And should you avoid them if you have celiac disease?
A few months ago, I picked up a product from a trendy gluten-free brand and noticed that it was also labeled “seed oil-free.” Then, when I was traveling to Austin, I dined at a gluten-free restaurant that advertised themselves as being seed oil-free. More recently, I walked past a hip fast casual gluten-free chain in New York City that proudly proclaimed they don’t use seed oils.
There’s been a lot of negative buzz around seed oils lately—but that doesn’t mean there are scientifically sound reasons to cut them out of your diet. Are seed oils really bad for you—and should you ditch them if you have celiac disease? I chatted with a variety of food and nutrition experts to find out.
Table of Contents
What are seed oils?
“Seed oils are a grouping of the oils extracted from a list of sources, some of which are not even seeds,” explains Mark Jensen, associate food consultant at Mendocino Food Consulting. “The eight most common sources listed are canola, corn, cottonseed, soybean, sunflower, safflower, grape, and rice bran.”
Seed oils are widely used in the food industry because they’re cost effective and shelf-stable, adds Tamar Samuels, RDN, CDN, co-founder and head of clinical partnerships at Culina Health.
“These oils are typically extracted using chemical solvents or mechanical presses, then refined to remove impurities,” says Samuels. This process isn’t exclusive to seed oils. “Other oils like olive oil also go through similar refining processes,” she says.
“Seed oils have become a target in the wellness world. Critics argue that they’re ‘pro-inflammatory’ due to their high omega-6 content and susceptibility to oxidation, especially in highly processed foods.” - Tamar Samuels, RDN, CDN, co-founder and head of clinical partnerships at Culina Health
Why have seed oils gotten such a bad rap lately?
If you read this newsletter, chances are you’re tapped into the health and wellness space—and that means you’ve probably heard influencers or people with a poor understanding of science and nutrition rail against seed oils.
“Seed oils have become a target in the wellness world,” notes Samuels. “Critics argue that they’re ‘pro-inflammatory’ due to their high omega-6 content and susceptibility to oxidation, especially in highly processed foods.”
Leah McGrath, RD, LDN, author of Build Up Dietitians Newsletter, adds that the anti-seed oil push seems to have coincided with the rise of the keto, carnivore, and “whole foods” movements.
These lifestyles involve a move away from consuming processed foods (which are made with seed oils) and an appeal to “nature/natural” foods, encouraging the consumption of butter, tallow, and lard as more “natural.” (As you’ll learn by the end of this post, natural doesn’t always mean healthier.)
Why are so many gluten-free businesses going seed oil-free?
Oftentimes, those who go gluten-free for lifestyle reasons will also avoid other ingredients they deem unhealthy. Seed oils are just the latest “bad” ingredient having a moment—and gluten-free businesses are starting to capitalize on that.
“Brands and restaurants are starting to label ‘seed oil-free’ to appeal to health-conscious or influencer-following customers who are actively avoiding ingredients they’ve been told are ‘bad,’ even when there’s no strong scientific reason to avoid them,” says Samuels.
McGrath says she thinks there’s been some very effective fear-based marketing about seed oils—and that can make life with celiac disease unnecessarily harder.
“It is unfortunate to see someone who has to restrict their diet due to medical reasons, like having celiac disease and not consuming gluten, also feel they also need to avoid seed oils when there is no medical reason for this and may just further complicate their efforts to enjoy meals out with friends or family,” she says.
The bottom line? “For people with celiac disease or gluten sensitivity, avoiding gluten is medically essential, but avoiding seed oils isn’t,” says Samuels.
“Brands and restaurants are starting to label ‘seed oil-free’ to appeal to health-conscious or influencer-following customers who are actively avoiding ingredients they’ve been told are ‘bad,’ even when there’s no strong scientific reason to avoid them.” - Tamar Samuels, RDN, CDN, co-founder and head of clinical partnerships at Culina Health
Are seed oils actually bad for you?
A little history lesson: Brittany Raftis, MScFN, RD, mentions in her recent newsletter that our consumption of seed oils has increased a lot since the 1960s. This is when large health authorities like the American Heart Association (AHA) started recommending we reduce our intake of saturated fats for heart health.
“In response, food manufacturers started seeking alternatives to traditional sources of saturated fat, such as butter, lard, and palm oil, and turned to seed oils instead,” she writes.
Fast-forward to today: Current health recommendations from the AHA and the US Dietary Guidelines (2020) recommend using liquid oils that contain less saturated fats and more monunsaturated fats, like canola oil in place of saturated fats like butter, lard, and tallow, says McGrath.
What does this all mean? Ahead, I’m busting some of the specific myths surrounding seed oils so you can see how they really impact your health.
Myth: Seed oils are bad for you.
There are no risks in eating seed oils, says Jensen. On the flip side, they actually have some benefits.
“Seed oils are a source of polyunsaturated fatty acids (PUFAs) like omega-3 (n-3) and omega-6 (n-6) fats, which play important roles in heart health, brain function, immune regulation, and hormone balance,” explains Samuels.
As Raftis notes in her newsletter, study after study shows PUFAs have positive health effects. She cites the following research in her piece:
A 2025 study published in JAMA Internal Medicine found that replacing 10 grams per day of butter with vegetable oil was associated with a 17% reduction in total mortality and cancer mortality.
A 2024 study published in JAMA Internal Medicine found that adults with a higher intake of plant-based fats—including vegetable oil—had a lower risk of dying from heart disease.
A 2021 study published in BMC Medicine found that replacing butter or margarine with vegetable oil was associated with lower mortality overall and lower mortality from specific diseases including heart disease, diabetes, cancer, and Alzheimer’s.
Myth: Seed oils are toxic.
One of the extraction methods for seed oils involves liquid hexane, says Jensen. Per Harvard Health Publishing, hexane is “a solvent that's hazardous in gas form but evaporates during oil processing, leaving limited if any residual hexane in the liquid form.”
Jensen says seed oil opponents claim hexane residues remain in the oil—and “because there is no government regulation to prove the veracity of this claim, they say that their theory is correct.”
Here’s the deal, though: The average person’s intake of any potential residual traces of hexane in oils and other foods is exponentially lower than from other sources, like gasoline, according to Harvard Health Publishing.
Myth: Seed oils are dangerous to cook with.
It’s true that repeatedly heating seed oils to high temperatures (which is what occurs in a restaurant deep-fryer, where the oil isn’t changed often) creates trans fats and other harmful substances, according to Harvard Health Publishing.
As for using seed oils in your own kitchen? Experts tell Consumer Reports that there’s absolutely no issue with cooking with seed oils at home.
Myth: Seed oils make you gain weight.
One common refrain I’ve heard from people in the wellness community is that seed oils make you gain weight. That’s not exactly true, though.
As noted in UCHealth Today, seed oils are calorically dense—and a diet that’s higher in fat and calories can lead to weight gain. But it’s important to note that people don’t eat seed oils by themselves—rather, they eat foods that have been cooked in these oils or have these oils as an ingredients, says McGrath.
These are often fried foods or highly processed foods, which can be high in fat, sodium, and sugar and have been linked to health issues, including high body weights.
However, according to Harvard T.H. Chan School of Public Health, it’s usually other components in these foods (like sugar and sodium) that are the culprit behind negative health outcomes—not seed oils.
Myth: Seed oils cause inflammation.
The final popular myth about seed oils is that the omega-6 fatty acids (aka linoleic acid) in them contribute to inflammation—and therefore chronic illness, says Jensen.
“To put it simply, opponents claim that linoleic acid is a precursor to inflammation, but studies have proven otherwise—and some have even shown it to combat inflammation, which suggests that inflammation is caused by something else,” he says.
Samuels explains that some of the negative linoleic acid claims are around the fact that it’s converted into arachidonic acid, a compound associated with inflammation. “While that conversion does happen, the evidence linking dietary omega-6 intake to increased inflammation in healthy humans is weak,” she says.
What’s more, Samuels shares that a 2022 meta-analysis of randomized controlled trials found no link between omega-6 supplementation and higher risk of cardiovascular disease. “The AHA echoed this in a 2019 pooled analysis of 30 cohort studies, showing no harm—and in some cases, potential benefit—of omega-6 consumption on heart health,” she adds.
Should you avoid seed oils?
In general, most people (including celiacs) don’t need to avoid seed oils. “There’s no strong evidence that seed oils cause harm when eaten in moderation, especially as part of a balanced diet,” says Samuels.
The only reason to skip seed oils would be if you have a severe food allergy or intolerance—“but these oils are typically processed to a degree that would eliminate any protein allergen which could cause an allergic reaction,” notes McGrath. You may also want to avoid seed oils if you have a lipid metabolism disorder, adds Samuels.
Both Samuels and McGrath think the focus is on the wrong thing (seed oils) in this conversation. “A better way to look at this would be to avoid consuming foods that are high in fats, like fried food, as they can contribute to excess calories, affect gut health, and increase inflammation—regardless of what they are fried in,” says McGrath.
So, if you’re looking to make helpful dietary changes, focus less on cutting out seed oils and more on adding in nutrient-dense foods, suggests Samuels. “Aim for a variety of fats—think olive oil, avocado, nuts, seeds, fatty fish—and let your overall eating pattern do the heavy lifting for your health,” she says.
Have you fallen for any of these seed oil myths? What nutrition myth would you like me to bust next? Drop a comment and let me know!
Sources
Mark Jensen, associate food consultant at Mendocino Food Consulting
Tamar Samuels, RDN, CDN, co-founder and head of clinical partnerships at Culina Health
Leah McGrath, RD, LDN, author of Build Up Dietitians Newsletter
The Grocery Edit. Are Seed Oils Bad? Let’s Break It Down.
American Heart Association. Saturated Fat. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/saturated-fats
American Heart Association. The American Heart Association Diet and Lifestyle Recommendations. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/aha-diet-and-lifestyle-recommendations
United States Department of Agriculture. Dietary Guidelines for Americans (2020 - 2025). https://www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf
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Great article, thanks for sharing!
It drives me bananas when people demonize an ingredient based on junk science and Internet rumors. So grateful for your deep dive into this topic, Christina!