Two Detrimental Factors for Sperm Quality

Poor semen quality, including a low sperm count, concentration, and motility, is an important cause of infertility.  Smoking, drinking, drugs, stress, poor nutrition and lack of exercise can all contribute to diminished quality, but there have been two recent reports of less-likely causes.

One report comes from the Journal of Fertility and Sterility, and deals with bisphenol A (BPA).  This substance is a chemical used in the production of the plastics used in baby bottles, food containers, and the lining of cans used for food and drinks.  This is in fact the 3^rd report in the last year to describe an association between urine BPA levels and reduced semen quality.  Four regions in China where there’s high exposure to BPA in the workplace provided samples from 218 men.  The researchers found that increasing urine BPA levels were statistically associated with a decreased total sperm count, decreased sperm concentration, and decreased sperm vitality and sperm motility.  Those with detectable urinary BPA levels had 2-4 times the risk of impaired sperm quality than those with undetectable levels.   Recent interest in the risks associated with BPA in the close environment receives a boost with this information.

The other report was from a presentation at the recent American Society for Reproductive Medicine meeting.  Researchers evaluated the semen quality and dietary fat intake of 91 men attending a Boston Fertility Clinic.  Participating men were aged 18 to 55, and were generally overweight (BMI over 25).  Those with the highest intake of saturated fat had as much as 41% fewer sperm than those with the lowest intake, and those with the highest intake of monounsaturated fat had 46% fewer sperm.  On the other hand, men with the highest intake of omega-6 polyunsaturated fats had greater sperm motility and more favorable sperm morphology.  

One should note that these two studies are ‘correlation studies’, i.e. they can show associations between two factors (usually a health condition and an environmental,  a nutritional, or a therapeutic agent), but they cannot prove ‘cause-and-effect’.  For that, one needs a prospective, well-controlled study, where the participants are randomized to receive the active agent or a control (ideally a placebo).  Obviously, it’s not usually feasible to fulfill these conditions when there’s evidence of a detrimental association, as in these two cases . . .