Professor Tim Spector: I was wrong about Vitamin D & sunlight! The 7 health habits he's changed his mind about

What health habits actually protect your brain and long-term health?

In this episode, Professor Tim Spector shares the seven health ideas he has changed his mind about after reviewing new research. From oral health and inflammation to vitamin D, sleep, and exercise, Tim explains the daily habits he now prioritises and helps us understand what we should do differently if the science changes.

Tim revisits 7 common health beliefs and explains how new evidence has shifted his thinking. He explores the link between oral health, inflammation and brain ageing, and discusses vitamin D, sunlight and omega-3s. The conversation also looks at sleep timing, exercise and how everyday habits interact with our biology.

Tim also shares the small changes he now makes in his own routine and provides practical ideas for incorporating them into your daily life.

We all know that science evolves as new evidence emerges, so if the research changes, should our daily health habits change too?

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Timecodes

00:00 Intro

04:00 The nutrition advice scientists completely reversed

08:30 How scientists decide if a health trend is real

10:30 The vitamin D discovery that fooled scientists for years

12:35 The one health belief Tim is more convinced about than ever

14:00 The public health threat Tim says may be worse than smoking

15:20 The new research linking oral health to dementia

17:05 How mouth bacteria may affect your brain

18:20 The test that revealed plastic in Tim’s blood

20:15 The simple changes Tim made to reduce microplastics

21:40 The omega-3 test most doctors still don’t use

23:05 Why Tim chose food over omega-3 supplements

24:50 The omega-3 measurement scientists now care about most

26:40 Should vegans worry about omega-3?

29:25 The vitamin deficiency Tim has had since he was 18

31:20 The surprising brain benefits of folic acid

33:10 Why supplements should be personalised

34:30 Why Tim changed his mind about vitamin D

36:15 The simple way sunlight doubled his vitamin D

38:10 Why we shouldn’t fear winter sun

39:45 The exercise change Tim made this year

42:05 The muscle supplement Tim thought was “complete rubbish”

43:30 The sleep rule Tim now follows every night

45:30 The unusual sleep experiment Tim tried

📚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

Ferment by Prof. Tim Spector

Good Mood Food (preorder) by Prof. Tim Spector

Free resources from ZOE

The Hormone Harmony Guide: Tuning Your Body’s Internal Orchestra

Eating for Better Brain Health: Your brain-gut blueprint

How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health

Live Healthier: Top 10 Tips From ZOE Science & Nutrition

Gut Guide - For a Healthier Microbiome in Weeks

Better Breakfast Guide

Mentioned in today's episode

What is your gut-brain connection and what role does nutrition play?

Oral Health and Dementia, Journal of Dental Research (2025)

Neuroinflammation: A Distal Consequence of Periodontitis, Journal of Dental Research (2022)

Vitamin D Supplementation and the Incidence of Fractures, JGIM (2024)

Does a good diet reduce your heart disease risk?

Vitamin B12 and Age-Related Cognitive Decline-Dementia and "Alzheimer's Disease", FNB (2024)

Vitamin D and Risk for Type 2 Diabetes, Annals of Internal Medicine (2023)

Effects of Creatine Supplementation and Resistance Training, Nutrients (2024)

Why you're probably breathing wrong (and what to do about it) | James Nestor

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Episode transcripts are available here.