Vitamin D has been in the news lately because of all the biological functions that require it. For example, vitamin D has been implicated in both bone and immune system health. Martin Blomberg Jensen led a team of Danish biologists in identifying another role for vitamin D. It appears to be involved in sperm motility.
For this study, 300 healthy men supplied both blood and semen samples. 44% of the men turned out to have low serum vitamin D levels. Those with low vitamin D also had a greater number of abnormal and/or slow moving sperm. I might point out that sperm have exactly one job, and that’s to swim fast. A slow sperm is a useless sperm. Because this work is only in the preliminary stages, the authors don’t recommend vitamin D supplementation as a treatment for male infertility. However, they don’t rule that out as a possibility down the road.
I’m sure it’s unnecessary to add that besides having other health consequences, achieving a low serum vitamin D level is not an effective form of birth control.