A study was forwarded from the Journal of Clinical Endocrinology and Metabolism discussing the relationship between vitamin D status and muscle mass and muscle fat in young women. Vitamin D insufficiency has now reached epidemic proportions and has been linked to increased body fat and decreased muscle strength. Whether vitamin D insufficiency is also related to adipose tissue infiltration in muscle is not known. The objective of the study was to examine the relationship between serum 25-hydroxyvitamin D (25OHD) and the degree of fat infiltration in muscle.

In the conclusion they found that vitamin D insufficiency is associated with increased fat infiltration in muscle in healthy young women.

The most important question, where does vitamin D come from?

The main source of Vitamin D is sunlight. The only other place to naturally get vitamin D is from fish. From an evolutionary standpoint, many of our ancestors might have ate a limited amount of fish, as they all did not all live near the ocean. But one thing is true about our ancestors, they spent a lot of time in the sun. Studies show that people that spend a lot of time in the sun can get ten times the amount of vitamin D we get today.

Just another reason to get outside and soak up some rays, the sun is a performance enhancer and will help with muscle mass.