If you've been told APOE4 means you're destined for Alzheimer's, the science says something very different.

As a vascular surgeon who has spent years treating the end-stages of preventable disease, I want to give you a clearer picture of what APOE4 actually does, and what it doesn't.

In this video, I break down:
- What the APOE4 gene is and how it affects your brain
- Why it raises Alzheimer's risk — but doesn't guarantee it
- The surprising evolutionary reason APOE4 exists in the first place
- What the science actually says about Alzheimer's prevention if you carry the allele
APOE4 is the most significant genetic risk factor for late-onset Alzheimer's. But risk is not destiny. Understanding the biology gives you real options — and that's exactly what this channel is about.

🔔 Subscribe for evidence-based prevention medicine — straight from the OR to your screen.
📩 Questions? Leave them below — I read everything.

I advise you to go through your clinician for testing. But if you want to do it on your own, you can order it here: https://www.ultalabtests.com/partners/lilyjohnstonmd/test/cardio-iq-apoe-genotype-test

Chapters:
0:00 APOE4 is not fate
0:24 What ApoE does in the brain
1:54 ApoE2, ApoE3, and ApoE4 explained
3:22 How APOE4 became linked to Alzheimer’s
4:23 How much APOE4 raises risk
5:37 Why APOE4 does not guarantee Alzheimer’s
6:50 What APOE4 is actually doing
9:46 Amyloid, lipid trafficking, and brain fuel
11:07 Why does APOE4 still exist?
11:29 APOE4 is the original gene
14:51 APOE4 as an immune-modulator gene
17:05 Ancient immune system, modern environment
19:03 The blood-brain barrier feedback loop
20:02 Same gene, different environment
21:36 The gene is fixed, but the provocation isn’t
22:55 What we’ll cover in Part 2
23:40 Should you test for APOE4?
25:04 Knowing turns fate into a head start

This content is for educational purposes only and does not constitute medical advice. Always consult your physician.

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🧬 About Dr. Lily Johnston

Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.

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