The Impact of Vitamin D on Weight Loss

Along with the increased prevalence of obesity, the incidence of vitamin D deficiency is rising with 10–60 % of adults having values lower than 20 ng/ml. Serum or plasma 25-hydroxyvitamin D (25OHD) is the most widely accepted measure of vitamin D status (deficiency <20 ng/ml, insufficiency 20–29 ng/ml, and sufficiency >30 ng/ml). Many studies have shown it is inversely associated with measures of obesity and that obese participants have lower suboptimal 25OHD levels compared with healthy weight participants. Adipose tissue sequesters the fat-soluble vitamin and this leads to lower levels in obese populations. It is also thought that obese people may spend less time outdoors, or expose less skin to the sun, which may lead to reduced synthesis of vitamin D.