What If We Got Sunlight All Wrong? The Truth About Vitamin D & Chronic Disease
Mark Hyman
14 jul 2025
Mindsip insights from this episode:
Understand melanoma's risk beyond sun exposure
Unlike basal and squamous cell cancers, the deadly skin cancer melanoma is not as strongly linked to sun exposure and can occur in non-sun-exposed areas.
Maintain vitamin D levels above 50 ng/mL to eliminate COVID death risk
An Israeli study found that if your vitamin D level was over 50 ng/mL, your risk of death from COVID was zero.
Avoid sunscreens with vitamin A to reduce skin cancer risk
You should be particularly careful with sunscreens containing vitamin A, as it can paradoxically make skin cancer more likely.
Perform simple self-test for vitamin D deficiency
You can perform a simple self-test for vitamin D deficiency by pushing your thumb hard on your shin; if it hurts, you are likely deficient.
Address chronic nutrient deficiencies to prevent long latency diseases
Chronic, low-level nutrient deficiencies can lead to "long latency deficiency diseases" like osteoporosis and cancer over many years.
Maintain vitamin D levels above 60 ng/mL to lower breast cancer risk
Women with vitamin D levels over 60 ng/mL had an 82% lower risk of breast cancer compared to those with levels under 20 ng/mL.
Boost vitamin D levels as aging reduces skin production
The average 70-year-old's skin creates only 25% of the vitamin D from sun exposure that a 20-year-old's does.
Aim for optimal vitamin D levels above 45 ng/mL
Standard lab reference ranges for vitamin D reflect a deficient population, whereas the optimal level for health should be over 45 or 50 ng/mL.
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