Vitamin D Deficiency? Here's What's Really Happening

Feb 16, 2026

Description

Are you one of the 1 billion people worldwide with a hidden deficiency? In this episode, Dr. Mark Hyman reveals the essential health tips you need to know about the profound impact of Vitamin D on our immune system.

While often called a vitamin, it’s actually a powerful hormone that controls over 1,000 genes and acts as a master key for your health. Dr. Hyman discusses how optimal levels can significantly prevent disease and even reduce the risk of severe outcomes from COVID-19 to near zero.

In this video, you’ll learn:

The "Shin Test": A simple way to check for deficiency at home.

The "Optimal" Range: Why "normal" lab results are often wrong.

Disease Prevention: How Vitamin D can lower breast cancer risk by 82%.

The Supplement Guide: Why Dr. Hyman says almost everyone should supplement for longevity.

Don't Guess Test. Dr. Hyman emphasizes the role of proper nutrition and supplements in maintaining overall health. Stop ignoring the warning signs and start taking control of your biology

(0:00) Introduction and overview of vitamin D's significance
(1:15) Vitamin D's role in health and disease
(5:25) Vitamin D's impact on the immune system and chronic diseases during COVID-19 (7:32) Vitamin D deficiency: statistics, symptoms, and associated diseases
(10:30) Sponsor: Function Health
(11:29) Vitamin D in disease prevention and the importance of sun exposure
(15:29) Ensuring adequate vitamin D through sun, supplements, and diet
(23:04) Identifying and managing risk factors for vitamin D deficiency
(27:31) Recap and recommendations for optimal vitamin D levels