Take vitamin D to raise testosterone, achieve a better body composition, and have better overall health. A new study in the European Journal of Endocrinology provides more support for ensuring your vitamin D levels are above par. This study is especially timely as we enter the darkest times in the Northern hemisphere when blood vitamin D levels continue to decline due to a lack of sun exposure.
This new study tested vitamin D and hormone levels in a large European population of 3051 men aged 40 to 79. Researchers found that men with vitamin D deficiency (below 50 nmol/l or 20 ng/ml) had significantly lower free testosterone and higher levels of oestradiol and leutenizing hormone, which all together indicate hypogonadism and poor reproductive health. It’s necessary to achieve adequate vitamin D levels to support optimal hormone production because there are vitamin D receptors in the hypothalamus and pituitary glands—both produce hormones and involved in metabolic and sexual health—and men have D receptors in the testis.
In addition to lower testosterone, the men with deficient and sub-optimal vitamin D (classified as 50 to 75 nmol/l or 10 to 29.9 ng/ml) had a higher body mass index, were less physically active, had poorer physical function, and greater incidence of depression. They also had higher rates of cardiovascular disease and diabetes—a disease that previous research has linked directly to low testosterone in men. On the flip side, men with the highest vitamin D levels had the highest testosterone levels, better body composition, and better overall health.
Researchers also tested the men for seasonal variability in vitamin D status over a year and found a clear trend of peak levels in August and lowest levels in April. This trend has been well documented in research and indicates that it is critical to get your vitamin D levels tested, especially during the winter months, so that you can supplement when you’re deficient. In this study sufficient levels were classified as greater than 75 nmol/l or over 30 ng/ml. This number is on the low side, and recommendations for adequate vitamin D vary based on the organization. The Vitamin D Council suggests achieving a level of at least 50 ng/ml. A general recommendation is that below 20 ng/ml is a deficiency, and for optimal levels you should shoot for 30 to 80 ng/ml. The only evidence of vitamin D toxicity is with levels over 100 ng/ml, and all reported cases have occurred when there was an error in dosing.
To achieve optimal levels, I generally suggest 5,000 IUs a day or a biweekly dose of 35,000 to 50,000 IUs. For detailed guidelines on how to raise your vitamin D levels for optimal health, please read "Low in D?"
Lee, D, Tajar, A., et al. Association of Hypogonadism with Vitamin D Status: The European Male Ageing Study. European Journal of Endocrinology. January 2012. 166, 75-85.