160. Dr. Kara Fitzgerald on Biological Age, Epigenetic Clocks, and the Future of Aging Reversal

Biological aging is no longer just a concept tied to time. It is something we can now measure, track, and influence through data, lifestyle, and targeted interventions that directly impact how our cells function and age.

In this episode of Extend, we sit down with Dr. Kara Fitzgerald, functional medicine leader, researcher, and author, to unpack how diet and lifestyle can directly influence epigenetics and biological age. We break down the difference between chronological and biological aging, how epigenetic clocks work across organs and systems, and why aging may be driven by both environmental exposures and deeper programmed mechanisms.

We also explore how polyphenols, nutrient-dense diets, and emerging interventions like Yamanaka mimetics may begin to shift the trajectory of aging at the cellular level and open new pathways for extending healthspan and peak performance.

Dr. Kara Fitzgerald is a functional medicine physician, researcher, and author of Younger You, known for her pioneering clinical studies demonstrating how targeted nutrition and lifestyle interventions can reverse biological age and reshape long-term health outcomes.

What We Discuss:

• (01:36) Aging, performance, and menopause

• (05:01) Healthspan vs peak span

• (08:39) The dark matter of nutrition

• (11:36) Polyphenols and urolithin A

• (13:12) Biological age and epigenetics

• (15:41) Epigenetic clocks and measurement

• (21:02) Exposomic aging

• (25:03) Programmed aging

• (28:20) Yamanaka factors

• (33:24) Yamanaka mimetics

• (36:29) Polyphenols and caloric restriction

• (40:33) Nutrition and biological age reversal

Thank You to Our Sponsors:

IM8: Try IM8 today with a 30-day money back guarantee. You can get 10% off your first order with code DRSHAH at https://im8health.com/discount/DRSHAH.

Momentous: Head to livemomentous.com/fiber and use code DRSHAH for up to 35% off your first order.

Learn more about Dr. Shah:

Website: drshah.com

Clinic: next-health.com

Instagram: darshanshahmd

Learn more about Dr. Kara Fitzgerald:

Website: drkarafitzgerald.com

Podcast: New Frontiers in Functional Medicine

Webinars: webinars

Instagram: drkarafitzgerald

Facebook: Dr. Kara Fitzgerald

You tube: @Drkarafitzgerald

X: @kfitzgeraldnd

Pubmed: Potential reversal of epigenetic age using a diet and lifestyle intervention: a pilot randomized clinical trial

Pubmed: Potential reversal of biological age in women following an 8-week methylation-supportive diet and lifestyle program: a case series

Pubmed: Dietary associations with reduced epigenetic age: a secondary data analysis of the methylation diet and lifestyle study