Positive PCOS

A positive and practical information resource on polycystic ovary syndrome

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PCOS & Vitamin D Deficiency

Posted by Allie on 14th May 2016

The link between PCOS and vitamin D
Photo: Unsplash.com

Are you getting enough vitamin D? Highly prevalent in the general population (1), vitamin D deficiency is also common in women with PCOS (2). Deficiency is linked with symptoms such as excessive hair growth (medical term for which is hirsutism), fertility difficulties and insulin resistance (2).

What is Vitamin D?

Vitamin D isn’t actually a vitamin but a fat-soluble hormone. It comes in different forms including D2, made in plants, and D3, synthesized by humans when skin is exposed to UVB rays in sunlight hence why vitamin D is often called the ‘sunshine vitamin’.

Vitamin D helps to maintain normal amounts of calcium and phosphorus in the body, and aids the absorption of calcium needed for healthy bones and teeth. A deficiency in vitamin D can cause rickets in children and osteomalacia in adults, a disease which causes the bones to become soft and weak. It also increases the risk of other health conditions including cancers, heart and autoimmune diseases (2).

What is the link between vitamin D and PCOS?

Although the exact mechanisms are unclear, there is a substantial amount of evidence demonstrating a relationship between vitamin D deficiency and insulin resistance (3), which many women with the condition suffer from.

A substantial amount of evidence [demonstrates] a relationship between vitamin D deficiency and insulin resistance

An increasing amount of evidence shows that a vitamin D deficiency can lead to menstruation and fertility problems. The chances of successful pregnancy are linked to higher levels of vitamin D. Women with excessive hair growth, a symptom of PCOS, have also been shown to have lower vitamin D levels and deficiency appears linked to high androgen levels (2).

Some studies have found that women with PCOS have higher or lower levels of vitamin D than those without the condition. Other studies have found that obese women with PCOS are at higher risk of deficiency (2). However, further research is needed to confirm whether there is a correlation between Body Mass Index (BMI) and vitamin D levels.

What are good sources of Vitamin D?

We make most of our vitamin D from exposing skin to direct sunlight for a short period of time depending on skin type and sensitivity. The British Dietetic Association recommend going out in the sun 2-3 times a week for at least 15 minutes a day. Be careful not to allow skin to get burned or red/pink. You can read more about vitamin D and sun safety on the NHS Choices website.

You can get vitamin D by eating certain foods however, even a healthy balanced diet alone is unlikely to provide all the vitamin D you need. The following foods are rich in vitamin D:

  • Oily fish such as salmon, tuna, mackerel, sardines and trout
  • Eggs
  • Foods fortified with vitamin D

Vitamin D supplements are also available. The European Food Safety Authority (4) have recommended that the tolerable upper intake level for vitamin D in adults is 4,000 IU (International Unit) per day. Studies have shown that a vitamin D supplement helps with insulin resistance and regulating periods. However, more research is needed to ascertain whether it is beneficial for pregnancy and with the management of PCOS (2).

How much vitamin D do I need?

Studies have shown that a vitamin D supplement helps with insulin resistance and regulating periods

The majority of people get sufficient amounts of vitamin D from the sun and a balanced diet. However, groups at risk of vitamin D deficiency include people who have limited exposure to the sun, darker skin tones, are aged 65 years and over, and women who are pregnant and breastfeeding.

If you’re concerned that you’re not getting enough vitamin D, please liaise with your medical practitioner or health professional.


Note that referenced or mentioned authors, websites and organisations are not affiliated with, nor endorsing, the content published on Positive PCOS.

1: J.H. Lee et al. 2008. Vitamin D Deficiency: An Important, Common, and Easily Treatable Cardiovascular Risk Factor? Journal of the American College of Cardiology. 52 (24): 1949-1956

2: R.L. Thomson, S.Spedding & J.D. Buckley. 2012. Vitamin D in the aetiology and management of Polycystic Ovary Syndrome. Clinical Endocrinology. 77: 343–350

3: Y.H.M. Krul-Poel et al. 2013. The role of vitamin D in metabolic disturbances in polycystic ovary syndrome: a systematic review. European Journal of Endocrinology. 169: 853–865

4: European Food Safety Authority. 2012. Scientific Opinion on the Tolerable Upper Intake Level of vitamin D. EFSA Journal. 10 (7): 2813

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