Vitamin D is surprisingly versatile. It is critical for bone health, and also for muscle strength. Vitamin D helps keep the immune system in shape to fight off infection and cancer. At adequate levels, it also reduces the risk of diabetes, high blood pressure and osteoarthritis.
But how to get enough vitamin D? New research shows that just 13 minutes of sun exposure a day three times a week in the summer is enough to bring vitamin D blood levels of light-skinned people into the adequate range. The British investigators predict that in North America fair-skinned people would need between nine and 16 minutes for a comparable beneficial effect. People with darker skin need more time in the sun. People at high risk of skin cancer should avoid even short periods of sun exposure. They may need supplements to get their blood levels up to the optimal point of 30 ng/ml of 25-hydroxy vitamin D.
