|
Consuming excess beef during pregnancy may affect fertility of male offspring, suggests a new study by researchers at the University of Rochester Medical Center in New York. Sons of mothers who ate beef seven or more times a week had low sperm counts, the study found.
This condition is thought to be caused by the anabolic of growth hormones used to treat cattle. Reporting in the he March 28 issue of Human Reproduction, the researchers said pesticides and other environmental contaminants might adversely affect the developing testes of the unborn fetus leading to low sperm counts.
The study followed 387 partners of pregnant women in five U.S. cities. The participants were born between 1949 and 1983. All men were asked to provide sperm samples, while their mothers filled out a questionnaire detailing their diet during pregnancy.
Mothers reported eating beef at least four times a week on an average, but 51 said they consumed beef seven or more times a week. This group of heavy beef eaters was also more likely to have consumed large quantities of red meat as well.
Lead researcher Professor Shanna Swan, of the University of Rochester and colleagues said men whose mothers consumed large amounts of beef during pregnancy had a 24 percent lower sperm count than men whose mothers had a lesser intake of the meat.
Professor Swan said growth-promoting hormones used in cattle were the likely culprit for the lessened fertility in these men. Natural as well as synthetic hormones are used for promoting growth in cattle in the United States and Canada. Estradiol, progesterone and testosterone are the natural hormones, while zeranol, trenbolone acetate and melengestrol acetate are the synthetic analogues.
"We're not saying that people should stop eating beef, and it's particularly important in pregnancy that women get enough protein," Swan said. "If women want to take action, they could try hormone-free beef or organic beef, although it's not proven, or reduce their consumption of beef or find some other protein."
When cattle are slaughtered, not all hormones are metabolized, meaning they could easily pass the placental barrier and affect the unborn fetus. In the United States the Food and Drug Administration regulates the amount of hormones permissible in cattle.
In Europe the use of these hormones was banned in 1988 and the EU frowns on US imports containing anabolic steroids. Earlier studies in laboratory mice have shown even trace quantities of estrogen affecting fertility in male offspring.
However this is the first study to examine human fertility vis-à-vis fertility. The researchers stressed that none of the men in the study had infertility, but 18 percent could be classed as "sub-fertile" by the World Health Organization.
The researchers are hoping to conduct the same study in Europe with men born after 1988. "If we did the same study, and there was an association, it couldn't be due to the hormones, because there aren't any," Swan said. "But if we do not see an association, that would actually point to the hormones. That's our plan."
treating cattle with anabolic steroids to promote growth is a fiercely debated issue. However the present study highlights some of the potential adverse effects on human health as a result of hormones used to treat cattle.
Women must not stop eating beef altogether, the researchers cautioned. Moderate amounts must be consumed in order to gain enough protein, they argue.
Writing in an accompanying editorial, Dr. Ted Schettler, an environmental health specialist at the Institute for Global Communications in San Francisco, said the study was small, but significant, "The more you look at dietary factors, the more you turn up interesting information about how diet during pregnancy affects lots of aspects of human health," he added.
 Add as favourites (47)
Powered by AkoComment Tweaked Special Edition v.1.4.4 |
Health 
