Dietary sources: dairy, milk fat differences

Longevity science is shifting fast. New discoveries are revealing that aging may be influenced not just by genetics or lifestyle, but by specific nutrients that regulate cellular health.

In this episode of Habits & Hustle, I sit down with Dr. Stephanie Venn-Watson to explore the discovery of C15, a fatty acid that emerged from decades of research studying Navy dolphins. Her work suggests that declining C15 levels may weaken cell membranes, accelerate aging, and increase vulnerability to metabolic disease.

We break down how this molecule works, why not all saturated fats are the same, and how modern dietary shifts away from full-fat dairy may be contributing to widespread nutrient deficiencies.

We also discuss how C15 interacts with longevity pathways like AMPK and mTOR, the same pathways targeted by drugs like metformin and rapamycin, and why researchers believe C15 may function as a geroprotector — a compound capable of slowing biological aging.

Dr. Stephanie Venn-Watson is a veterinary epidemiologist, CEO of Seraphina Therapeutics, and author of The Longevity Nutrient. Her work bridges marine biology, epidemiology, and human longevity science to uncover how nutrition influences cellular aging.

What’s Discussed

• (07:48) How studying Navy dolphins led to a breakthrough in longevity research
• (10:31) Why dolphins are a powerful model for studying human aging
• (16:04) The discovery of C15 and its role in metabolic health
• (17:33) Why not all saturated fats are harmful
• (20:25) How C15 interacts with longevity pathways like mTOR and AMPK
• (22:23) How modern diets may be creating a widespread C15 deficiency
• (24:30) The link between C15 deficiency and accelerated cellular aging
• (27:11) How dairy fat became the primary source of C15 in humans
• (31:18) Why C15 may qualify as a “geroprotector”
• (34:28) How to measure C15 levels through blood testing
• (39:23) Signs of cellular fragility and biological aging in blood markers
• (43:02) How C15 may influence inflammation and autoimmune conditions
• (50:20) The lifestyle factors that matter most for longevity
• (55:17) Other ways to increase C15 levels through diet and exercise

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Find more from Jen: 

Website: https://jennifercohen.com

Instagram: @therealjencohen

Books: https://jennifercohen.com/books

Speaking: https://jennifercohen.com/speaking-engagement

Find more from Stephanie Venn-Watson:

Website: https://fatty15.com

Instagram: https://www.instagram.com/fatty15/?hl=it 

LinkedIn: https://www.linkedin.com/in/stephanievennwatson/

Book: The Longevity Nutrient