Low vitamin D may mean fatter, weaker muscles

March 08, 2010

     Insufficient blood levels of vitamin D may be associated with the accumulation of fat in muscle tissue, leading to lower muscle strength, says a new study. The study included 90 young women aged 16 to 22. It found that almost 60 % of them were vitamin D insufficient, and that muscle fat levels were higher in the Vitamin D insufficient women, compared with women with normal vitamin D levels. The findings are said to be the first to show a clear link between Vitamin D levels and the accumulation of fat in muscle tissue, and add to an ever growing body of science supporting the benefits of maintaining healthy vitamin D levels.
     In collaboration with Dr Vincente Gilsanz from the University of Southern California, researchers from McGill University in Montreal recruited young Californian women and measured blood levels of 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form of the vitamin, as well as levels of fat, muscle mass, and percent muscle fat. Results showed that almost 60 % of the women had insufficient levels of Vitamin D, equivalent to blood levels lower than 29 nanograms per millilitre, of which 24 % were classed as vitamin D deficient (levels below 20 ng/ml).
     Vitamin D levels were found to be strongly linked to the percent of fat in muscle, with lower D levels resulting in higher fat content. “This reciprocal association between vitamin D status and muscle fat was not previously reported and is unexplained and intriguing,” wrote the researchers in the JECM. The researchers noted surprise at their findings since the women were all healthy young women living in California, with adequate exposure to sunshine. “We are not yet sure what is causing vitamin D insufficiency in this group,” said Dr Kremer. The study is published online ahead of print in the Journal of Clinical Endocrinology and Metabolism.