Do Seed Oils Cause Inflammation? What the Science Actually Says
Your Instagram feed says seed oils are poison. Your favorite wellness influencer swears they’re destroying your gut. Meanwhile, Johns Hopkins, Stanford, and three systematic reviews in 2025 say the opposite.
So who’s right?
The claim: seed oils cause inflammation
The argument goes like this: seed oils (canola, soybean, sunflower, corn) are high in omega-6 fatty acids, specifically linoleic acid. Omega-6 produces inflammatory compounds. Therefore, seed oils = inflammation.
It sounds logical. It’s also not what the research shows.
A 2025 systematic review evaluated clinical studies on seed oils and their effects on lipid profiles, inflammatory markers, and glycemic control. Their conclusion: seed oils did not increase inflammatory markers (Lee et al., Nutr Rev, 2025).
What the largest studies found
A 2025 study analyzed blood markers from nearly 1,900 people. Higher levels of linoleic acid — the omega-6 fat everyone fears — were linked to lower inflammation and better cardiometabolic health (Kaviani et al., Mol Nutr Food Res, 2025).
Stanford Medicine reviewed decades of data tracking hundreds of thousands of people. Their conclusion: eating more unsaturated fats (including seed oils) was associated with lower death rates (Petersen et al., Br J Nutr, 2024).
The omega-6/omega-3 ratio — but not how you think
Here’s where it gets nuanced. The ratio of omega-6 to omega-3 fatty acids does affect health. But the problem isn’t seed oils themselves — it’s the overall dietary pattern.
A 2021 review found that a high omega-6/omega-3 ratio was associated with increased risk of autoimmune diseases, asthma, and allergies (DiNicolantonio et al., Mo Med, 2021). But this doesn’t mean “avoid all seed oils.” It means “eat more omega-3s.”
The fix isn’t eliminating seed oils. The fix is adding fatty fish, walnuts, flaxseed, or a quality omega-3 supplement to your diet.
👉 Nordic Naturals Ultimate Omega — the one I recommend for anyone who doesn’t eat fish 2-3x per week.
The real inflammatory triggers
If seed oils aren’t the problem, what is?
Ultra-processed foods — not because of seed oils, but because of added sugars, refined carbohydrates, artificial additives, and the complete absence of fiber and micronutrients. The food is inflammatory. The oil is incidental.
Chronic stress — cortisol directly activates inflammatory pathways. No amount of avocado oil fixes a stress problem. If your cortisol is high, read our guide on adaptogens that actually lower it.
Poor sleep — sleep deprivation increases inflammatory markers like CRP and IL-6 within 24 hours.
Sedentary behavior — regular movement is one of the most potent anti-inflammatory interventions we have.
Gut dysbiosis — your microbiome regulates systemic inflammation. Processed food destroys gut bacteria.
What to actually do
Eat more omega-3s — fatty fish 2-3x per week, or a quality fish oil supplement. Nordic Naturals Ultimate Omega is the one I recommend.
Focus on whole foods — the inflammatory problem is ultra-processed food, not the specific oil used in it.
Fix your sleep — this matters more than any dietary change. Magnesium glycinate at night can help restore your sleep rhythm.
Move daily — even 20 minutes of walking reduces inflammatory markers.
Manage stress — cortisol is inflammatory. Meditation, breathwork, or just going outside.
The bottom line
Seed oils are not toxic. Linoleic acid is not poison. The internet wellness industry found a villain, and seed oils were easy targets.
The science consistently shows that seed oils do not increase inflammation when consumed as part of a balanced diet. The real issue is ultra-processed food, chronic stress, poor sleep, and inactivity. Fix those, and the oil in your pan becomes irrelevant.
Coming soon
- At-home hormone testing (coming May 15) — what to test and when
- The truth about cortisol curves — why you crash at 2pm
This post contains affiliate links. If you purchase through these links, I may earn a small commission at no extra cost to you. I only recommend products I’ve personally tested or that have strong research backing.
👉 Nordic Naturals Ultimate Omega
👉 Magnesium Glycinate
References:
Lee K et al. Are Seed Oils the Culprit in Cardiometabolic and Chronic Diseases? Nutr Rev (2025). PubMed
Petersen KS et al. Perspective on the health effects of unsaturated fatty acids. Br J Nutr (2024). PubMed
DiNicolantonio JJ et al. The Importance of Maintaining a Low Omega-6/Omega-3 Ratio. Mo Med (2021). PubMed
Kaviani E et al. Synergic Effects of Omega-6 Fatty Acids on Immune System. Mol Nutr Food Res (2025). PubMed
Mercola J. Historical rise of cancer and dietary linoleic acid. World J Clin Oncol (2025). PubMed