By Jimmy Downs

Thursday Oct 04,2012 (foodconsumer.org) -- Kaiser Permanente researchers suggest that exposure to bisphenol A (BPA) may damage a man's fertility or capability to have children and cause sexual dysfunction.  BPA, a plasticizer is used to make hard transparent plastics, which are commonly used to make food and beverage containers.

D. K. Li of Kaiser Foundation Research Institute, Kaiser Permanente in Oakland, California and colleagues published a study in Fertility and Sterility showing that exposure to BPA was associated with lower semen quality. 

Li and colleagues analyzed data from 218 men with and without BPA exposure who resided in four regions in China where high exposure to BPA in the workplace was not uncommon. They compared these two groups of men for semen parameters.

After adjustment for potential confounders, higher urine BPA level, indicating higher exposure, was statistically significantly correlated with an decrease in sperm concentration, total sperm count, sperm vitality, and sperm motility.

Specifically, the study found that "Compared with men who did not have detectable urine BPA levels, those with detectable urine BPA had more than three times the risk of lowered sperm concentration and lower sperm vitality, more than four times the risk of lower sperm count, and more than twice the risk of lower sperm motility."

However, the urine BPA level was not correlated with either semen volume or abnormal sperm morphology.  

The researchers concluded "These results provide the first epidemiological evidence of an adverse effect of BPA on semen quality."

BPA as an endocrine disruptor has been associated with damage to the brain, reproductive system and immune system, according to the National Toxicology Program.

The same Kaiser Permanente group also conducted another study early linking BPA exposure to men's sexual dysfunction.  The study in Journal Andrology showed that men who had a higher urine level of BAP were more likely to have sexual dysfunction like erection dysfunction among other things.

The study of 427 male workers in certain regions in China where high levels of BPA exposure were common found BPA negatively affected all major domains in male sexuality. That is, high BPA exposure was associated with decreased sexual desire, more difficulty having an erection, lower ejaculation strength and decreased satisfaction with sex life.

The harmful effect was also found in men who were exposed to only environmental sources.

The researchers concluded "Our results reveal a correlation between a biological measure of urine BPA level and declining male sexual function. This finding may enhance the understanding of the BPA effect in human populations, and may have important public health implications given the widespread human exposure to BPA."

Still by the same group of researchers at  Kaiser Permanente Northern California, a study published in Human Reproduction quantified how likely it is to a man with certain exposure to BAP to suffer sexual dysfunction.

In that study, Dr. Li et al found that men with occupational exposure to BPA were 4, 4.5, 7.1 and 4 times as likely as those without occupational exposure to BPA to have reduced sexual desire, erectile dysfunction,  ejaculation difficulty, and reduced sexual satisfaction, respectively.

And the researchers also found a dose responsive association between cumulative BPA exposure and risk of sexual dysfunction.  High exposure was linked to high severity of sexual dysfunction.

It is impossible for men to avoid BPA exposure.  To minimize the damage from the toxic chemical, men may try by all means to avoid the exposure. Additionally, taking vitamin A dietary supplement may also help reduce the damage induced by BPA. 

Hazubi Aikawa of Graduate School of Science University of Tokyo in Japan and colleagues published a study in Cell Tissue Research suggesting that vitamin A supplementation may ameliorate the BPA induced sperm damage.