Low vitamin D decreases sex hormones, raises disease risk

A Hopkins research team led by Erin Michos recently found conclusive evidence indicating the strong relationship between vitamin D deficiency, low estrogen level and increased risk of cardiovascular and bone diseases in males.

Vitamin D is a fat-soluble substance found naturally in foods such as fatty fish, eggs and milk. It can also be produced by the body through exposure to sunlight. Today, vitamin D can even be found in vitamin supplements.

This nutrient is essential in aiding the body's absorption of calcium, reducing inflammation and improving other immunity functions. Blood levels of vitamin D below 20 nanograms per milliliter are considered unhealthy.

Previous studies have shown that deficits in vitamin D and low levels of estrogen both increase risk of osteoporosis and heart diseases. Recent findings indicate the presence of a direct link between vitamin D concentrations and estrogen levels.

It has long been known that cholesterol levels in blood affect bone and arterial health. Interestingly, vitamin D, estrogen and testosterone are all produced from cholesterol as a precursor. This fact led scientists to investigate the direct relationship between vitamin D and sex hormones.

In a subset of a study designed to determine the effect of vitamin D level on risk of diseases, blood samples from a group of men were analyzed. Both estrogen and testosterone concentrations were measured.

These sex hormones can either be unattached, and thus free-circulating, or attached to a protein called sex hormone binding globulin (SHBG).

At first, low testosterone and estrogen levels seemed to be independent of vitamin D deficiency, although low sex hormone concentrations did point to increased rates of osteopenia - the early stage of osteoporosis - heart diseases and high blood pressure in men.

When estrogen to SHBG ratios were compared however, rates of heart and bone diseases both increased when both estrogen and vitamin D decreased. Every unit decrease of estrogen to SHBG ratios caused an 89 percent increase in bone disease in men deficient in vitamin D, and only a 64 percent increase in men with healthy levels of vitamin D.

Michos plans on extending the study towards women in her future research. She also mentions clinical trials testing whether or not vitamin D supplements can prevent deaths caused by various cardiovascular diseases, such as strokes and heart attacks.