Administration of vitamin D improves sexual function in men, according to researchers in a recent study published in the International Journal of Endocrinology.
“Erection is a complex phenomenon which implies a delicate and coordinated equilibrium among the neurological, vascular, and the tissue compartments,” according to corresponding author Giancarlo Balercia, MD, Division of Endocrinology, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, Ancona, Italy.
Vitamin D is primarily known for its role in bone health and calcium-phosphorous homeostasis. It also appears to be involved in endocrine disease, including diabetes.
More recently, researchers have suggested that vitamin D plays a role in sexual function.
“Recent clinical works have suggested that low vitamin D levels may somehow be associated with the occurrence of sexual disturbances, especially erectile dysfunction, even if not all the studies agree on this point,” wrote the researchers. “These results need confirmation because of their potential revolutionary approach to the treatment of sexual dysfunction.”
Researchers retrospectively analyzed the records of 114 men (median age: 64 years) who sought medical care for sexual dysfunction at their Italian andrology clinic starting in 2003.
The researchers made a sexual assessment using the International Index of Erectile Function-15 questionnaire (IIEF-15), which involves five aspects of male sexual life, including erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction.
The researchers analyzed a subsample of 41 participants (median age: 65 years) to longitudinally evaluate the effect of vitamin D supplementation on sexual function.
In this subsample, researchers administered cholecalciferol (50,000 or 100,000 IU) either weekly, every 2 or 3 weeks, or monthly. They administered supplements to patients whose vitamin D levels dropped below 30 ng/mL.
On the basis of logistic regression of the entire sample, the researchers found that higher levels of 25(OH) vitamin D were significantly associated with high values of total testosterone and all of the IIEF questionnaire parameters. Furthermore, higher testosterone levels were significantly and positively associated with increased levels of erectile function and IIEF scores.
In the subsample that received vitamin D supplementation, total and free testosterone levels increased and erectile function improved.
“Our cross-sectional study shows that vitamin D levels are directly able to influence all sexual function parameters,” wrote the authors. “Longitudinal evaluation of our study clearly shows the improvement of erectile function after vitamin D replacement therapy, also demonstrating the direct influence of the vitamin D treatment.”
The researchers proposed several possible mechanisms for vitamin D’s effect on sexual function. For example, vitamin D could improve endothelial integrity, and vitamin D may directly protect endothelial cells against oxidative stress. Alternatively, the activation of vitamin D by the antioxidant pathway may result in the production of nitric oxide, which promotes penile vascular dilation.
One major limitation of this study is its retrospective nature—based on the 14-year practice of one group of physicians.
“Our work shows that vitamin D is important for the wellness of male sexual function and that vitamin D administration improves sexual function,” concluded the authors. “If our data will be further confirmed, vitamin D evaluation might be included in the near future in the clinical workup protocol of male sexual dysfunction.”