Note: The comments on this blog are for information only. Do not make any changes in sunlight exposure, tanning-bed exposure or nutritional habits without first consulting a medical professional.
Can sunlight or vitamin D make a difference in sexual behavior or fertility? That is a difficult question, but there are indications that sunlight exposure or vitamin D intake do influence hormones, fertility and sexual behavior. Now that I have your undivided attention, let’s examine the evidence. After all, with the current ridiculous preoccupation with sex, if we could somehow increase sexual performance through the use of tanning beds, the industry could take its place right alongside “male enhancement” drugs! That, unfortunately, is not going to happen; there is no evidence of such an effect of vitamin D. Nevertheless, what we do know about vitamin D, sexual activity, sperm and fertility is interesting. It is exceptionally important to women who want to become pregnant.
In 1939, Dr. Abraham Myerson measured initial levels of circulating testosterone in men and exposed their various body parts to UVB light. After five days of chest exposure sufficient to cause reddening, circulating testosterone increased by 120%. After eight days without additional UV exposure, testosterone returned to initial levels. When the genital area was exposed, testosterone levels increased by 200%! Considering our sex-obsessed society, it is surprising that no studies followed up. Some doubt has been cast on this work, because testosterone levels tend to peak in winter, when UVB is not available from sunlight.
Other experiments show that rats maintained on D-deficient diets produce fewer sperm, but sperm production increases when vitamin D is again provided. Vitamin D restores fertility to deficient rats and proper testicular function in deficient chickens. Female rats mated to deficient males also have 73% fewer successful pregnancies than those mated to vitamin D-sufficient males. The ovaries and testes of rats that lack vitamin D receptors (VDR) do not function fully and properly, and vitamin D deficiency profoundly reduces sperm production. However, that condition is reversible when vitamin D is restored to optimal levels. Also, most women who are infertile due to polycystic ovary disease, resulting in loss of menstrual cycles, experience restored menstruation and can become pregnant when vitamin D levels are increased.
If vitamin D increases fertility, conception rates should be higher in summer than in winter. In higher latitude countries, where UVB availability varies dramatically during the year, conception rates are indeed at their highest in late summer and birth rates are highest the following spring.
Vitamin D levels are exceptionally low in people with chronic kidney disease, and sufferers generally experience sexual problems, including erectile dysfunction in men, decreased libido and fertility in both sexes, and menstrual abnormalities in women. Whether vitamin D is responsible or simply a result of kidney disease is not known.
Considering this information, it might seem that vitamin D deficiency would be an effective method of birth control if one were willing to accept a greatly increased risk of depression, cancer, heart disease, MS, diabetes and osteoporosis!
(All references for the above are found in the book, Vitamin D3 and Solar Power)