Vitamin D may affect testosterone levels

An insufficient supply of vitamin D seems to be linked to testosterone deficiency, reports a Korean study.

In the observational study, blood vitamin D and testosterone concentrations were measured in 652 men over 40 years old (1). The study results showed that vitamin D deficiency, defined by levels less than 20 ng/ml, was independently associated with testosterone deficiency. Men with vitamin D deficiency were 2.65 times more likely to have testosterone deficiency compared to those with levels above 20 ng/ml. These associations persisted after adjusting for age, season, body composition, chronic disease, alcohol use, smoking, and exercise.

The researchers noted that research indicates a potential role of vitamin D in reproductive health outcomes, such as in polycystic ovarian syndrome and erectile dysfunction (2). In addition, serum calcium is essential for male reproductive function, especially in spermatogenesis, sperm motility, and the acrosome reaction (3). Because vitamin D is a major regulator of calcium metabolism, it could influence male sex hormone synthesis. Testosterone plays an important role in maintaining muscle mass, mood, the production of red blood cells, bone health, and sexual function (4). Testosterone deficiency can cause a man to lose his sex drive, experience erectile dysfunction, develop osteoporosis, feel depressed, and/or lose muscle mass. Low testosterone levels are also a suggested risk factor for cardiovascular disease, cancer, and all-cause mortality.

1. ak Y. J. et al. Serum 25-hydroxyvitamin D levels and testosterone deficiency in middle-aged Korean men: a cross-sectional study. Asian Journal of Andrology. Published online December 2014.
2. Blomberg Jensen M. et al. Vitamin D receptor and vitamin D metabolizing enzymes are expressed in the human male reproductive tract. Hum Reprod. 2010; 25:1303-1311.
3. Blomberg Jensen M. et al. Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa. Hum Reprod. 2011; 26:1307-1317.
4. Khaw K. T. et al. Endogenous testosterone and mortality due to all causes, cardiovascular disease, and cancer in men: European prospective investigation into cancer in Norfolk (EPIC-Norfolk) Prospective Population Study. Circulation. 2007; 116:2694-701