Omega-3 fatty acids have long been lauded for heart health benefits. Yet, emerging research now points to an even more profound impact, directly on our most complex organ: the brain. Today, we delve into the critical, often misunderstood, role of omega-3s in cognitive function, mental well-being, and even the prevention of neurodegenerative conditions like dementia. We are joined by Dr. Bill Harris, a globally recognised authority in omega-3 fatty acid research. Bill is a Professor at the University of South Dakota and has over 300 peer-reviewed publications. His foundational work includes pioneering studies on fish oil in the 1980s and shaping American Heart Association scientific statements. In this episode, Dr. Harris - along with ZOE's Chief Scientist Professor Sarah Berry - illuminate why most individuals may be operating with suboptimal omega-3 levels, and the tangible implications this has for mood regulation, anxiety, and long-term brain resilience. We navigate nuances between omega-3 types like EPA and DHA, debunk common misconceptions surrounding plant-based sources and mercury content in fish, and explore the precise methods for assessing and improving your own "Omega-3 Index." Unwrap the truth about your food 👉 ⁠⁠Get the ZOE app⁠ 🌱 Try our new plant based wholefood supplement - ⁠Daily 30+⁠ *Naturally high in copper which contributes to normal energy yielding metabolism and the normal function of the immune system Follow ZOE on⁠ Instagram⁠. Measure your Omega 3s https://omegaquant.com/https://omegaquant.com/ Timecodes 00:00 Do Omega 3s Really Protect Your Brain? 01:46 Are We Deficient in Omega 3? 02:15 Plant vs. Fish: Omega 3 Sources Explained 03:34 Are EPA & DHA Really "Essential"? 05:03 The Omega 3 Family Tree: ALA, EPA, and DHA 07:05 Plant Based Myth: Omega 3 Conversion Rates 11:00 The "Optimal" Omega 3 Level: Are You There? 12:51 Historical Omega 3 Intake: What Did Our Ancestors Eat? 14:19 Are Omega 3s Only For Heart Health? 15:13 Why Fish Oil First Made Headlines 18:47 Why Are Omega 3s so Great for Your Heart 21:01 Clearing the Confusion: Omega 3 Supplements for Heart Health 25:11 Omega 3s and Longevity 28:18 Omega 3s and Brain Health: The Latest Science 29:15 Dementia Risk: Omega 3 Levels in the Brain 30:01 Mental Health Breakthrough: Omega 3s for Anxiety & Depression 32:41 EPA vs. DHA for Depression: The Surprising Findings 35:28 The Blood Brain Barrier: Can Omega 3s Reach Your Brain? 38:40 Measuring Your Omega 3 Index: How to Get Tested 42:20 Mercury in Fish: Is it a Real Concern? 45:19 Farmed vs. Wild Salmon: What's the Difference? 48:50 The Omega 6 to Omega 3 Ratio: A Useless Metric? 54:50 Vegan & Vegetarian Options: Algae Based Omega 3s 📚Books by our ZOE Scientists ⁠The Food For Life Cookbook⁠ ⁠Every Body Should Know This by Dr Federica Amati⁠ ⁠Food For Life by Prof. Tim Spector⁠ Free resources from ZOE ⁠Live Healthier: Top 10 Tips From ZOE Science & Nutrition⁠ ⁠Gut Guide - For a Healthier Microbiome in Weeks⁠  Mentioned in today's episode⁠ Associations of plasma omega-3 fatty acid levels and reported fish oil supplement use with depression and anxiety: A cross-sectional analysis from the UK Biobank, 2025 The Association Between Plasma Omega-3 Fatty Acids and Suicidal Ideation/Self-harm in the United Kingdom Biobank, 2025, Plasma Omega-3 Fatty Acids and Risk for Incident Dementia in the UK Biobank Study: A Closer Look, 2013, NutrientsFish consumption advice is depriving children of neurolipids and other nutrients essential to brain and eye development, 2025, NeuroToxicology Have feedback or a topic you'd like us to cover? Let us know ⁠here⁠. Episode transcripts are available ⁠here⁠.