In an intriguing new study, researchers have determined that a womanÃ¢â‚¬â„¢s level of beef consumption during pregnancy may have adverse effects on their sonsÃ¢â‚¬â„¢ sperm levels and fertility. Scientists believe that the increased presence of growth hormones in beef products may be responsible for the problem. The results of the study are to be published in Human Reproduction, which is a monthly journal of the European Society of Human Reproduction and Embryology (ESHRE).
According to a report by the ESHRE, Ã¢â‚¬Å“New research has shown that women who ate a lot of beef while pregnant had sons who were more likely to suffer from poor sperm quality as adults, and it suggests that the growth promoters used in cattle may play a role in these menÃ¢â‚¬â„¢s reduced fertility.Ã¢â‚¬Â
Lead author Shanna Swan, of the University of Rochester, said, Ã¢â‚¬Å“These findings suggest that maternal beef consumption is associated with lower sperm concentration and possible sub-fertility, associations that may be related to the presence of anabolic steroids and other xenobiotics in beef.Ã¢â‚¬Â
The study examined hundreds of men living in the United States and who were born between 1949 and 1983. According to the ESHRE, researchers found that Ã¢â‚¬Å“those whose mothers ate more than seven beef meals a week had a sperm concentration that was over 24 percent lower than in men whose mothers ate less beef. In addition, three times more sons of high beef consumers had a sperm concentration that would be classified as sub-fertile according to World Health Organization standards, in comparison to men whose mothers ate less beef.Ã¢â‚¬Â
Dr. Swan also noted, Ã¢â‚¬Å“The number of beef meals consumed by the mother was significantly and inversely related to her sonÃ¢â‚¬â„¢s sperm concentration. Sons of high beef consumers had an average sperm concentration of 43.1 million sperm per millimeter of seminal fluid, while sons of mothers who ate less beef had an average of 56.9 million sperm–a statistically significant difference of 24.3 percent. Among sons of mothers whose beef consumption was not high, only 5.7 percent had sperm concentration below the WHO threshold for sub-fertility of 20 million sperm per millimeter of seminal fluid. This was significantly less than the 17.7 percent of men whose mothers were high beef consumers who fell below this threshold.Ã¢â‚¬Â
Researchers point out that the findings may only apply to North America, where the use of growth hormones in cattle is still common. The synthetic hormone diethylstilbestrol (DES) was used in the U.S. since 1954, but was subsequently banned for use in cattle in 1979. However, other hormones such as oestradiol, testosterone, progesterone, zeranol, trenbolone acetate, and melengestrol continue to be used.
Scientists have determined that residues of these chemicals remain in the meat after slaughter, and evidence is increasing that these steroids and other growth-promoting agents may have more significant effects on child development than previously realized. While the FDA has attempted to regulate their usage to avoid adverse effects in humans eating meat, their defined level of Ã¢â‚¬Å“acceptable daily intakeÃ¢â‚¬Â may not be stringent enough to protect consumers. Significantly, these hormones have been banned in Europe since 1988.