Vitamin D is important for many reasons and deficiencies are also very common. The study reviewed here is interesting, since it examined the relationship between serum 25-hydroxyvitamin D (25OHD) and fat infiltration in muscle (Gilsanz V, et al. 2000).
25OHD is the most common way of testing to determining vitamin D status. The participants in this study were women aged 16-22 years residing in California.
Approximately 59% of the participants were found to be vitamin D insufficient with 25OHD levels of 29 ng/mL or lower and 24% of these women were deficient with a 25OHD of 20 ng/mL or less.
The percent muscle fat was found to be significantly lower in the women with normal serum 25OHD than in women with insufficient levels and deficient levels of 25OHD.
The researchers concluded that vitamin D insufficiently is associated with increased fat infiltration in muscle in healthy young women.
These women lived in California where there are plenty of sunny days, but even so the majority of the study participants did not get enough vitamin D.
Even if you do not get enough sun exposure without sunscreen it is easy to correct. Supplementing the diet with 1000-2000 IU of vitamin D3 daily will take care of that.
Gilsanz Vicente, Kremer Arye, Mo, Ashley O., Wren, Tishya A.L., Kremer, Richard. Vitamin D Status and Its Relation to Muscle Mass and Muscle Fat in Young Women. Journal of Clinical Endocrinology & Metabolism, doi:10.1210/jc.2009-2309.