48. Vitamin D Supplements: Do They Work?

Most people take vitamin D pills because their doctor, a commercial, or a supplement aisle told them to.  But do vitamin D supplements actually improve your health? In this episode, Miles Hassell MD breaks down what the evidence really shows — and why vitamin D sources found in nature may be far more powerful. We dive into the massive gap between blood levels of vitamin D and whether supplements actually work, the risks of "false confidence" in pills, and the often-overlooked benefits of sunlight, food, weight management, and real lifestyle habits. Key Takeaways Supplements rarely improve outcomes. Large, well-designed studies show vitamin D pills generally do not reduce cancer, heart disease, fractures, falls, or total mortality. Natural sources matter. People with naturally higher vitamin D levels (sunlight, diet, activity) live longer and healthier — but synthetic vitamin D doesn't recreate that benefit. The "healthy user effect." Higher vitamin D often reflects healthier habits, not pills. Sunlight is the #1 source. Just 10–15 minutes of midday sun can significantly boost levels and also increases nitric oxide, improves metabolism, and supports cardiovascular health. Supplement benefits are limited. Possible small improvements for respiratory infections and progression from prediabetes to diabetes — but usually too small to be clinically meaningful. Toxicity exists. Over-supplementation or manufacturing errors can cause dangerously high levels and hypercalcemia. Food sources are powerful. Oily fish, cod liver oil, free-range eggs, and sunlight-exposed mushrooms all meaningfully improve vitamin D status. Lifestyle > pills. Exercise, weight management, and whole-food nutrition remain far more impactful than supplements. Get your copy of Good Food Great Medicine, 4th ed.: https://a.co/d/1D6hIYM More references can be found at www.GreatMed.org Would you like Dr. Hassell to answer your question on the air?  Contact us! Phone/text: 503-773-0770 e-mail: [email protected] EIN: 88-326-7056   Write us a letter.  We love to hear from you.  This podcast is sponsored by our generous listeners.    Send questions, comments, and support to: GreatMed.org 4804 NW Bethany Blvd., Suite I-2, #273 Portland OR 97229