By David Liu, PHD

Monday April 22, 2013 (foodconsumer.org) -- A new study in Asian Journal of Andrology suggests that both high and low serum vitamin D may not be good for semen quality.

Ahmad O Hammoud and colleagues conducted the study and found sperm concentration, sperm progressive motility, sperm morphology, and total progressively motile sperm count were best in men having vitamin D between 20 ng/mL and 50 ng/mL.

The study involved 170 healthy men recruited from the general population, who completed health questionnaires and donated blood and semen samples for the study.

Men with serum vitamin D greater than 50 ng/mL were found to have lower sperm concentration, sperm progressive motility, worse sperm morphology, and total progressively motile sperm count than those who had vitamin D between 20 and 50 ng/mL.

Men with lower than 20 ng/mL vitamin D were found to have lower total sperm count and total progressive motile sperm count, compared with those having their serum vitamin D between 20 and 50 ng/mL.

It is not clear how other factors may also affect the semen quality as at least body mass index was found in this study inversely associated with serum vitamin D levels.