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.

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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

Mitochondrial decline is one of the most overlooked drivers of aging, impacting energy, muscle function, cognitive performance, and immune resilience long before symptoms become obvious. Many of the changes we associate with aging may actually stem from a loss of cellular efficiency and the body's ability to renew itself.

In this episode of Extend, I sit down with Dr. Anurag Singh, Chief Medical Officer at Timeline, to unpack the science behind urolithin A and how mitochondrial health shapes longevity. We break down how the gut microbiome influences cellular function, why mitophagy declines with age, and what clinical research shows about improving muscle strength, recovery, metabolic health, and immune function.

We also explore how targeted supplementation and lifestyle strategies can help restore mitochondrial quality and support long-term performance and resilience.

Dr. Anurag Singh is a physician-scientist with an M.D. in internal medicine and a Ph.D. in immunology, currently serving as Chief Medical Officer at Timeline, where he leads the development of advanced nutritional and skincare products focused on mitochondrial and cellular health.

What We Discuss:

• (04:58) Drug vs nutraceutical and what urolithin A actually is

• (06:23) Gut microbiome differences and why most people don't produce it

• (08:11) How urolithin A is made from diet and polyphenols

• (10:25) Effective dosing and supplementation strategy

• (15:32) What mitochondria are and why they matter for aging

• (21:26) Mitophagy and how mitochondrial quality declines over time

• (23:43) Main drivers of mitochondrial damage

• (26:24) How urolithin A supports cellular renewal

• (28:55) Muscle aging, strength, and performance

• (33:07) Clinical trial results in older and sedentary adults

• (35:32) Effects on recovery in elite athletes

• (37:07) Brain health and neurodegeneration research

• (43:00) Immune system impact and inflammation

• (47:29) When to start and how to think about supplementation

Thank You to Our Sponsors:

Timeline: Visit timeline.com/drshah for 20% off a subscription on top of the new starting price of $79.

Learn more about Dr. Shah:

Website: drshah.com

Clinic: next-health.com

Instagram: darshanshahmd

Learn more about Dr. Anurag Singh:

Website: https://www.timeline.com/

Modern life is quietly accelerating biological aging, from posture and movement patterns to sleep disruption, chronic stress, and constant digital stimulation. Many of the symptoms people experience daily, like pain, fatigue, brain fog, and disconnection, may reflect a deeper misalignment with how the human body was designed to function.

In this episode of Extend, I sit down with Dr. Kavin Mistry, board-certified neuroradiologist and author of Primal Health Design, to unpack how modern lifestyles are reshaping our biology and accelerating aging. We break down how posture, movement, circadian rhythm, nutrition, and environment influence brain and spine health, and why reconnecting with our primal design is essential for long-term resilience and performance.

We also explore how daily practices like morning sunlight, grounding, deep work, and intentional routines can help restore alignment with your biology and create more energy, clarity, and longevity in a fast-moving, AI-driven world.

Dr. Kavin Mistry is a board-certified neuroradiologist, author, and thought leader in longevity and human performance, known for developing the Primal Health Design framework to help individuals reconnect with their biology and reverse the hidden effects of modern living.

What We Discuss:

• (05:04) Seeing accelerated biological aging in brain and spine scans

• (06:02) Childhood exposure to primal tribes and longevity insights

• (10:19) Tech neck, posture, and modern spinal degeneration

• (12:09) Nerve compression, numbness, and daily symptoms

• (15:03) Primal posture and how alignment reduces aging

• (18:07) Strength training, hanging, and back development

• (21:17) Deep squat and reversing sedentary damage

• (24:14) Walking, movement, and daily activity patterns

• (25:01) Grounding, inflammation, and connection to earth

• (28:01) Morning sunlight and circadian rhythm optimization

• (31:27) Sleep, stress, and parasympathetic recovery

• (32:11) Nutrition, microbiome diversity, and prebiotics

• (36:44) Stillness, presence, and flow state

• (42:20) Tribe, relationships, and loneliness in modern life

• (48:44) Purpose, service, and greater cause

• (51:02) Finite life awareness and long-term decision making

• (56:07) AI, time leverage, and becoming more human

• (59:47) Morning and night routines as the foundation
  

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. Mistry:

Website: kavinmistrymd.com

Instagram: kavinmistry.md

LinkedIn: Kavin Mistry MD

YouTube: @kavinmistrym.d