Saturday Jan 7, 2012 -- A new study released recently in the joournal Clinical Endocrinology suggests that maintaining a high level of serum vitamin D may increase the level of testosterone, the major male sexual hormone.
The study led by Katharina Nimptsch at Havard School of Publich Health and colleagues shows that men whose vitamin D levels in their blood were in the highest quintile have 8 percent higher levels of total testosterone, compared to those whose vitamin D levels were in the lowest quintile.
Nimptsch et al in their report say that a small trial has already suggested that vitamin D might boost the production of testosterone in men and experimental studies in animal models and at least one cross-sectional study also show a positive link between plasma 25-hydroxyvitamin D or 25(OH)D and testosterone.
A similar association was also observed between levels of serum vitamin D and free testosterone.
Study results show that once the plasma vitamin D level reached about 75 to 85 nmol per liter, then vitamin D does not seem to have an effect on testosterone anymore. At low levels, the association between vitamin D and testosterone was linear.
The researchers concluded "This study supports previously reported positive associations between vitamin D and testosterone although we did not observe parallel seasonal variation patterns. Possible causality and direction of the vitamin D-testosterone association deserve further scientific investigation."
It is unknown whether low vitamin D leads to low testosterone or vice versus.
There is a good possibility that men have high levels of vitamin D have high levels of the male hormone in the first place. If you have more testosterone, you are more aggressive and physically active and you will do more outdoor activities and get more sun-exposure (more vitamin D). That is probably the reason behind the association.
Testosterone, which is also found, but low in women, is very important for men. Low testosterone or or testosterone deficiency or medically known as hypogonadism, can lead to decreases in muscle mass, changes in cholesterol levels, decrease in hemoglobin and possibly mild anemia, fragile bones, decrease in body hair.