Vitamin D may help to optimise muscle, according to scientists at the University of Birmingham. new facts increased levels in the body. The study involved 116 healthy volunteers, those aged between 20 and 74 years. Participants mingle where the level of ‘active and inactive’ levels of vitamin D have measured along with physical characteristics including body fat, slim body, muscle mass and size. Women with a healthy body composition and body fat is lower, there are no markers ‘inactive’ lack of vitamin D. The analysis is based on the findings of active vitamin D levels lower in women with increased body fat.