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."

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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

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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, Nutrients
Fish consumption advice is depriving children of neurolipids and other nutrients essential to brain and eye development, 2025, NeuroToxicology

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Episode transcripts are available ⁠here⁠.