Ricci Flow Nutrition Podcast · Cameron Borg

Michael Holick: Vitamin D & Leveraging Sunlight For Health

·59 min·3 clips

Holick says a bottle of Sephadex LH20 led him to identify the major circulating form of vitamin D on Thanksgiving morning.

1. Ricci Flow Nutrition Podcast episode on Michael Holick focuses on vitamin D, sunlight, and human health. 2. Cameron Borg interviews Michael Holick, an American endocrinologist and vitamin D researcher whose work includes the active form of vitamin D and the circulating assay. 3. The episode asks how Holick identified vitamin D's active form and why he thinks sensible sun exposure matters. 4. Holick says he entered vitamin D research after professors steered him to Dr. DeLuca at the University of Wisconsin. 5. He describes failing a biochemistry prelim, being told to consider pharmacology or physiology, and insisting on becoming a biochemist. 6. Holick says Dr. Avioli sent 100 milliliters of blood from patients with hypoparathyroidism, which let him search for the human circulating vitamin D form. 7. He says a bottle of Sephadex LH20 on a shelf helped him separate the material and identify the major circulating form on Thanksgiving morning. 8. Holick says that breakthrough completed his master's degree in three months and launched the hunt for the active form of vitamin D. 9. He describes a race with Kodachek's group in Cambridge and Tony Norman's group in California to isolate the activation step. 10. Holick says the Cambridge work showed the kidneys, not the intestine, activated vitamin D. 11. He explains that after 17 chromatography methods and about 500 micrograms of junk, he changed the chemistry by silating hydroxyl groups. 12. Holick says that final separation let his team determine the structure and publish two weeks ahead of Cambridge. 13. He says he completed his PhD in 1971, became a postdoc, entered medical school, and published 42 major papers in five years. 14. Holick explains that he wanted to know why sunlight makes vitamin D and studied time of day, latitude, sunscreen, and skin pigmentation. 15. He says skin cells have a vitamin D receptor, and adding the active form of vitamin D made keratinocytes stop growing and mature. 16. Holick says he and a roommate chemically made the active form of vitamin D, which was then used for children with rickets and kidney failure patients with bone disease. 17. He describes a psoriasis trial using the compound mixed into Vaseline and says the topical treatment worked on one arm compared with plain Vaseline. 18. Holick says vitamin D receptors were also found in prostate and cancer cells, and he links better vitamin D status with lower risk of some deadly cancers. 19. The conversation moves to dosage, hunter-gatherer blood levels, and studies showing Maasai herders at 40 to 60 nanograms per mL and lactating women producing enough vitamin D in milk at 6,400 units per day. 20. Holick closes by arguing that UVA is the main driver of skin damage, that full-spectrum sun exposure has different effects than morning-only or late-afternoon exposure, and that sunlight biology has been underfunded when dermatologists sit on review panels.

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