VITAMIN D UPDATE: New study challenges one-size-fits-all approach to vitamin D supplementation guidelines. “The first key insight is that ambient UVB emerges as a critical predictor of vitamin D status, even in a place like the UK, which receives relatively little sunlight. The second is that age, sex, body mass index (BMI), cholesterol level, and vitamin D supplementation significantly influence how individuals respond to UVB. For example, as BMI and age increase, the amount of vitamin D produced in response to UVB decreases.”