Vitamin D deficiency is extremely common in women, especially those living in Northern climates, as we cannot absorb enough vitamin D from the sun through the winter months, and tend to cover up through the summer. The effects of vitamin D on immune function, mood and calcium absorption are well known, but vitamin D can have a profound effect on hormone balance in women with polycystic ovarian syndrome especially.
Polycystic ovarian syndrome, or PCOS is a very common hormonal disorder associated with menstrual irregularity, infertility, high androgens levels causing acne and excessive hair growth, and polycystic ovaries. PCOS is associated with an increased risk for both diabetes and cardiovascular disease, and one of the most significant underlying imbalances is insulin resistance.
Many studies have shown that vitamin D deificiency may exacerbate symptoms of PCOS, and that appropriate supplementation can reduce insulin resistance, help acne and hirsutism, and improve fertility. Here is a summary of the research:
- Insulin resistance: In studies, women with PCOS were given vitamin D supplements, resulting in lower fasting and stimulated glucose and insulin levels, less insulin resistance and lower triglycerides. (1) (2) (3)
- Fertility and reproductive function: Vitamin D supplementation resulted in improved menstrual frequency and regularity, and also better fertility rates. (2) (3) (4) (5)
- Androgens – acne and hirutism (excessive hair growth): Studies showed lower testosterone, free testosterone and DHEAS levels, as well as reduced acne with regular vitamin D supplementation. (2) (3) (4)
The key message from this research is that vitamin D levels can have a significant effect on hormone balance, menstrual regularity and fertility, especially in women with PCOS. Vitamin D supplementation is essential through the winter months in North America, and for anyone without regular sun exposure.
It is important to test vitamin D levels though (blood test), as absorption of vitamin D through sun and also through nutritional supplements can vary tremendously. A safe starting dose of vitamin D3 is 3000 IU daily through the winter months in North America (end of October – end of April), and 1000 IU daily through the summer. It is essential however to test your own vitamin D levels in order to determine the optimal dosage for you.
- Kotsa, K., Yavropoulou, M.P., Anastasiou, O., et al (2009) Role of Vitmain D treatment in glucose metabolism in polycystic ovarian syndrome. Fertility and Sterility, 92, 1053-1058.
- Selimoglu, H., Duran, C., Kiyici, S. et al. (2010) The effect of vitamin D replacement therapy on insulin resistance and androgen levels in women with polycystic ovarian syndrome. Journal of Endocrinological Investigation, 33, 234-238.
- Wehr, E., Pilz, S., Schweighofer, N. et al. (2009) Association of hypovitaminoisis D with metabolic disturbances in polycystic ovarian syndrome. European Journal of Endocrinology, 0, EJE-9-EJE0432.
- Thys-Jacobs, S., Donovan, D., Papadopoulos, A., et al. (1999) Vitamin D and calcium dysregulation in the polycystic ovarian syndrome. Steroids, 64, 430-435.
- Rashidi, B., Haghollahi, F., Shariat, M. et al. (2009) The Effects of Calcium-Vitamin D and Metformin on Polycystic Ovary Syndrome: a Pilot Study. Taiwanese Journal of Obstetrics and Gynecology, 48, 142–147.
- Thomson, R., Spedding, S., Buckley, J. (2012) Vitamin D in the Aetiology and Management of Polycystic Ovary Syndrome. Clin Endocrinol, 77(3):343-350.