Vitamin D deficiency appears to occur frequently in women with PCOS, and may be a contributing factor to some of the biochemical abnormalities seen in this condition.
In a study of 13 women with PCOS, five were found to have obvious vitamin D deficiency and three others had borderline-low vitamin D status.(1) All 13 women were treated with vitamin D2 at a dose of 50,000 IU once or twice a week, and also received 1,500 mg of supplemental calcium per day.
Of the nine women with absent or irregular menstruation prior to vitamin D treatment, seven experienced normalization of their menstrual cycles within two months and the other two became pregnant. Dysfunctional uterine bleeding also resolved within two months in both cases in which it had been present.
Other studies have shown that some women with polycystic ovary syndrome had sub-optimal levels of vitamin D.(2,3) Low vitamin D has been clearly linked to insulin resistance and obesity.
In other words, the heavier you are and the more insulin resistant you are, the more likely it is that your vitamin D is too low.
