Are seed oils truly harmful? Do omega-6 fats like linoleic acid increase inflammation, oxidative stress, or chronic disease risk? Or is this just another wellness myth gone viral?
In this episode, I’m joined by Dr. Bill Harris—one of the world’s leading experts on dietary fats and cardiovascular health—to unpack the science on linoleic acid, an essential omega-6 fat found in foods like nuts, seeds, and vegetable oils.
We kick off by discussing Dr Harris’ reaction to American fast food chain Steak ‘n Shake’s decision to swap out seed oils for beef tallow. Why has linoleic acid become such a scapegoat? And what does the science actually say?
We take a close look at the evidence—from randomised controlled trials to large-scale biomarker studies—and explore how this essential fat affects inflammation, cholesterol, oxidative stress, blood sugar, and risk of chronic disease.
In this episode, we cover:
- The origins of omega-6 controversy and the omega-6 to omega-3 ratio
- Whether linoleic acid is truly “pro-inflammatory”
- What the highest quality human studies say about disease risk and mortality
- Oxidation, lipid peroxidation, and the truth about heating seed oils
- How linoleic acid compares to saturated fat in terms of your risk of disease
- Why removing seed oils from the food supply could backfire
- The real drivers of chronic disease—and what actually deserves our attention
- How Dr Harris recommends you think about choosing cooking oils at the grocery store
We also address the broader issue of cherry-picked mechanistic studies and why outcome data—like heart attacks and mortality—need to be front and centre when we assess health claims.
Bill brings deep expertise and scientific humility to this conversation. If you’ve felt confused by the anti-seed oil narrative, this episode will hopefully bring clarity and reduce some of the fear.
- Omega-6 Fats and Health Overview (00:00)
- Why the Review Was Updated (01:22)
- What Is Linoleic Acid? (06:47)
- Linoleic Intake Over Time & Health Links (12:45)
- Research Methods and Key Evidence (16:25)
- Omega-6 and Inflammation Explained (41:00)
- Common Myths About Seed Oils (44:37)
- The Oxidation Concern with Seed Oils (49:20)
- Omega-6 vs Omega-3: The Real Story (53:39)
- Blood Sugar, Insulin & Linoleic Acid (01:03:48)
- Heart Health and Linoleic Benefits (01:05:44)
- Cancer Risk and Seed Oils (01:13:49)
- Public Health and Future Research (01:16:55)
- How to Use Vegetable Oils Wisely (01:25:17)
- Wrap-Up and Takeaway Advice (01:32:22)
You can learn more about Dr Bill Harris’ research at the Omega Quant and Fatty Acid Research Institute websites. To connect with Omega Quant team, you can access their Instagram, Twitter, and Facebook pages.#
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Enjoy, friends.
Simon
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More about Dr Bill Harris
Dr. Bill Harris is one of the world’s preeminent experts in the field of omega-3 fatty acid research. His work focuses on the roles that these fatty acids play in cardiovascular and neurocognitive health. The author of more than 300 scientific papers on fatty acids and health, Dr. Harris is a professor in the Department of Medicine in the Sanford School of Medicine at the University of South Dakota, the co-inventor of the Omega-3 Index, founder of OmegaQuant Analytics, and president and founder of the Fatty Acid Research Institute (FARI).
Further readings and supporting studies:
- Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association
- Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality
- Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39 740 adults from 20 prospective cohort studies
- Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies
- Adipose tissue content of ω-6 polyunsaturated fatty acids and all-cause mortality: A Danish prospective cohort study
- Randomized trials of replacing saturated fatty acids with n-6 polyunsaturated fatty acids in coronary heart disease prevention: Not the gold standard?
- Diet-heart disease hypothesis is unaffected by results of analysis of recovered data from Minnesota Coronary Experiment
- Are Seed Oils the Culprit in Cardiometabolic and Chronic Diseases? A Narrative Review
- ω-6 Polyunsaturated Fatty Acids and Cardiometabolic Health: Current Evidence, Controversies, and Research Gaps
- Comparison of the effects of flaxseed oil and sunflower seed oil consumption on serum glucose, lipid profile, blood pressure, and lipid peroxidation in patients with metabolic syndrome
- Incidence of cancer in men on a diet high in polyunsaturated fat
- Sigma Nutrition Podcast | Episode 504: Vegetable Oil vs. Saturated Fat – Analysis of the LA Veterans Study
- Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies
- HHS secretary praises burger chain for ‘RFK’ing’ their french fries, calls on other companies to join MAHA | Fox News
- Linoleic acid, glycemic control and Type 2 diabetes
- Dietary linoleic acid and risk of coronary heart disease: a systematic review and meta-analysis of prospective cohort studies
- Are Omega-3s Good or Bad For Your Heart? | Examining the Evidence | The Proof Podcast EP #325
- Reduction in saturated fat intake for cardiovascular disease
- Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association
- Comparison of the effects of flaxseed oil and sunflower seed oil consumption on serum glucose, lipid profile, blood pressure, and lipid peroxidation in patients with metabolic syndrome
- Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies
- Reduction in saturated fat intake for cardiovascular disease
- Relationship of Dietary Linoleic Acid to Blood Pressure
- Low-density lipoproteins cause atherosclerotic cardiovascular disease. 1. Evidence from genetic, epidemiologic, and clinical studies. A consensus statement from the European Atherosclerosis Society Consensus Panel
- Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomised controlled trial
- Beneficial effects of linoleic acid on cardiometabolic health: an update
- Butter and Plant-Based Oils Intake and Mortality
- How Industrial Seed Oils Are Making Us Sick | Kriss Kresse
