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Research proposes mechanism behind the role of vitamin D in polycystic ovarian syndrome

Posted on: April 12, 2017   by  Amber Tovey


A new study discovered a mechanism underlying the benefits of vitamin D supplementation for PCOS.

Polycystic ovary syndrome (PCOS) is a common hormonal disorder, affecting approximately 6%-10% of reproductive-aged women. PCOS is characterized by irregular menstrual cycles, low fertility, polycystic ovaries and excessively high levels of androgens. Androgens are steroid hormones that promote male characteristics. The two main androgens are androsterone and testosterone. 

Women with PCOS also face an increased risk of type II diabetes, high blood pressure, depression and anxiety.

While the cause of PCOS remains unclear, research suggests that vascular endothelial growth factor (VEGF) dysregulation likely plays a role in its development. Women with PCOS have significantly higher levels of VEGF than women without PCOS.

Research has also found that VEGF is the key mediator in the development of ovarian hyperstimulation syndrome (OHSS), a medical condition that women with PCOS are at risk for developing. OHSS is a condition in which the ovaries become swollen, resulting in rapid weight gain, abdominal pain, vomiting and shortness of breath.

Studies suggest PCOS is associated with vitamin D deficiency. In addition, vitamin D supplementation has been shown to improve total testosterone levels in vitamin D deficient women with PCOS.

Furthermore, studies have found that vitamin D supplementation decreases VEGF production. Therefore, researchers recently hypothesized that vitamin D may improve PCOS symptoms by controlling VEGF. They conducted a randomized controlled trial (RCT) to test their hypothesis.

A total of 68 vitamin D deficient women with PCOS were enrolled in the RCT. The women were divided into two groups; 35 of the women were assigned the vitamin D group and 18 were placed in the placebo group. The treatment group received 50,000 IU of vitamin D3 once weekly for eight weeks, and the control group received a matching dummy pill for the same duration.

Before and after the intervention, the researchers measured vitamin D levels and various hormones, such as progesterone and testosterone. They were also interested in whether vitamin D supplementation led to clinical improvements. They specifically looked at hirsutism, presence of acne, blood pressure and intermenstrual intervals. Hirsutism refers to the presence of male-pattern hair growth in women, which is a common symptom of PCOS.

Here is what the researchers found:

  • Average vitamin D levels significantly increased in the treatment group from 16.3 ng/ml to 43.2 ng/ml (p < 0.01).
  • Average vitamin D levels remained similar in the control group, changing from 17.0 ng/ml to 17.4 ng/ml (p = 0.85).
  • The vitamin D group experienced significant reductions in hirsutism scores, intermenstrual intervals and triglyceride levels (p < 0.05).
  • No significant changes in cholesterol levels, free testosterone levels or blood pressure occurred in either group.
  • VEGF levels significantly decreased in the vitamin D group, but not in the control group (1106.4 pg/ml to 965.3 pg/ml and 893.1 to 866 pg/ml, respectively).
  • The decline in VEGF levels was correlated with the decrease in triglyceride levels, but not the decrease in hirsutism or intermenstrual intervals.

The researchers concluded,

“In conclusion, we have demonstrated that vitamin D supplementation in vitamin D-deficient women with PCOS significantly decreases serum VEGF levels correlating with a significant decrease in serum triglycerides. These data suggest a possible molecular mechanism by which vitamin D mitigates PCOS symptoms.”

The researchers continued to state,

“[The data] also underscores the need to investigate a potential role of vitamin D treatment in the incidence or severity of ovarian hyperstimulation syndrome in women with PCOS undergoing follicular stimulation.”

The Vitamin D Council recommends that women with PCOS take 5,000 IU/day of vitamin D3.  After 3 months of 10,000 IU/day have a vitamin D blood test to make sure your vitamin D level 25(OH)D is around 40 – 60 ng/ml.


Tovey, A. & Cannell, JJ. Research proposes mechanism behind the role of vitamin D in polycystic ovarian syndrome. The Vitamin D Council Blog & Newsletter, April 6, 2017.


Mohamad, I. et al. Vitamin D Decreases Serum VEGF Correlating with Clinical Improvement in Vitamin D-Deficient Women with PCOS: A Randomized Placebo-Controlled Trial. Nutrients, 2017.  

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Research proposes mechanism behind the role of vitamin D in polycystic ovarian syndrome

A new study discovered a mechanism underlying the benefits of vitamin D supplementation for PCOS.

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