Science Update

New study demonstrates the effects of vitamin D on numerous aspects of PCOS

Polycystic ovarian syndrome (PCOS) is a condition associated with irregular menstrual periods, infertility, obesity, diabetes, excess hair growth, acne, and other hormonal difficulties. Past research has looked at the effect of combining lifestyle changes with metformin in those with PCOS. It was found that lifestyle modifications had a positive impact, helping to improve weight loss, body mass index (BMI), and menstruation.

According to a new study just published in Gynecological Endocrinology, researchers demonstrated the effects of vitamin D supplementation on insulin resistance, visceral fat, and adiponectin in vitamin D deficient women with PCOS.

Pharmaceutical interventions provide some improvements with PCOS but they do not correct many of the underlying factors and often have side effects that may not be tolerated by patients. Also, many patients with PCOS are overweight and have dietary habits that exacerbate the condition.

In this randomized, placebo-controlled clinical trial, 36 women with PCOS ages from 20 to 38 years with plasma 25OHD <20 ng/mL were randomized into two groups. Individuals received 50,000 IU of oral vitamin D3 once a week or placebo for 8 weeks. Visceral adipose tissue, insulin resistance (HOMA-IR), HOMA-B, QUICKI, and circulating adiponectin were compared at baseline and at the end of the 8 week period.

As a result, the individuals in the vitamin D group had significantly decreased fasting plasma glucose levels and increased homeostasis model of assessment-estimated B cell function (HOMA-B), adiponectin, and serum vitamin D levels.

Other Nutrients to Consider

Studies have shown that an inositol deficiency is common in women with PCOS, as there appears to be a reduced ability for them to process, metabolize, and effectively use inositol from foods. As a result, the nutritional requirements of those with PCOS may not be met by a simple change in the diet and that inositol should be viewed as a conditionally essential nutrient in these women.

The conversion of myo-inositol to D-chiro-inositol is of interest here because this conversion appears to be impaired in women with PCOS. Thus, it is important to always include D-chiro-inositol with myo-inositol through supplementation. D-chiro-inositol is the more potent form of inositol for supporting insulin resistance; however, myo-inositol is needed for oocyte quality and maturation. Therefore, supplementing with D-chiro-inositol alone cannot not fulfill myo-inositol’s roles that are specific and different from D-chiro-inositol, since it does not convert to myo-inositol.

Essential fatty acids should also be considered. Fish oils help to improve insulin sensitivity and reduce inflammation, and most individuals with insulin resistance are deficient in EFAs.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS


Source: Seyyed Abootorabi, Ayremlou P, et al. The effect of vitamin D supplementation on insulin resistance, visceral fat and adiponectin in vitamin D deficient women with polycystic ovary syndrome: a randomized placebo-controlled trial. Gynecol Endocrinol. 2018 Jun;34(6):489-494. doi: 10.1080/09513590.2017.