In November 2016 researchers Australia published the results of their study to assess the association between vitamin D, inter- and intra-muscular fatty tissue and insulin resistance in 40 women with and 30 women without polycystic ovary syndrome. In addition, 10 women with and 6 women without polycystic ovary system who had a BMI of over 27 kg/m² undertook an exercise regime for a 12-week period. Levels of vitamin D, insulin resistance, fasting glucose and insulin, visceral fat, inter- and intra-muscular fatty tissue and total body fat were analysed. Results showed that women with polycystic ovary syndrome and low levels of vitamin D had the highest level of insulin resistance, and that those with polycystic ovary syndrome and a higher amount of inter- and intra-muscular fatty tissue had lower vitamin D levels as well as insulin resistance. Overweight women with a pre-exercise vitamin D level of over 30 nmol/L had a lower degree of insulin resistance as well as a decreased amount of visceral and total body fat. This result did not appear to change when polycystic ovary syndrome status was taken into consideration. Higher vitamin D levels prior to starting an exercise regime may therefore improve exercise-induced body changes and insulin resistance in overweight women.
Scott D et al. Associations of Vitamin D with Inter- and Intra-Muscular Adipose Tissue and Insulin Resistance in Women with and without Polycystic Ovary Syndrome. Nutrients. 2016 Nov 30;8(12). pii: E774.