Mothers ate beef while pregnant, tendency having low sperm counts on her son

While mothers having pregnancy and consumed beef tendency have a lower sperm count on her son suggesting the hormones given to cattle may make people less fertile, researchers wrote in a study.

The concentration of sperm in the semen of men whose mothers ate beef more than seven times a week was 24 percent lower than men whose mothers ate less, said researchers led by Shanna Swan, director of the Center for Reproductive Epidemiology at the University of Rochester in New York.

Men with low sperm counts were three times more likely to have mothers who ate beef more than seven times a week, the study found. The findings may be the “tip of the iceberg” of revelations showing the impact of hormone use among animals, said Frederick vom Saal, a professor of biological sciences at the University of Missouri.

“The risks associated with exposure during development to hormonal residues in beef should be revisited” by regulators, vom Saal wrote in a commentary accompanying the study.

Men whose wives were attending prenatal clinics in five U.S. cities, including Iowa City and Los Angeles, were asked to donate sperm and to question their mothers about eating habits. A total of 387 men born between 1949 and 1983 participated. The study was published on line today in the journal Human Reproduction.

Hormone Use

“It’s been known for a long time that very low levels of hormones can impact fetal development,” said Swan, the head researcher, in a telephone interview yesterday. Until now, “there have been no studies on the effect these hormones might have on reproduction.”

U.S. and Canadian cattle ranchers routinely use hormones in their livestock, including testosterone and progesterone, to encourage growth. The animals don’t metabolize or excrete all of the hormones before being slaughtered, so they remain in the meat in measurable levels. The U.S. Food and Drug Administration sets acceptable levels for the hormones.

“Growth promotant use in cattle production is safe, and nothing in this epidemiological study changes that fact,” said Mary Young, the executive director of nutrition for the National Cattlemen’s Beef Association, in a statement yesterday. “As a mother and registered dietitian, I can tell you that I am very confident in the safety of beef.”

Other Factors

Other factors such as pesticide use and lifestyle factors may have played a role in lowering sperm counts, and more research is needed, wrote Swan, who has studied environmental effects on reproductive health for two decades.

“Whether prenatal exposure to anabolic steroids is responsible for our findings in whole or in part could be clarified by repeating this study in men born in Europe after 1988, when anabolic steroids were no longer permitted in beef sold or produced there,” Swan said.

The men’s own diets didn’t have an impact on sperm quality, and the shape and mobility of the sperm were unaffected, the study showed. Any research relying on self-reported food consumption is prone to error in how that intake is measured.

“It is widely accepted that food recall can be notoriously poor from even a day or a week before, let alone multiple decades,” said Randy Huffman, vice president of scientific affairs for the Washington-based American Meat Institute, in a statement.

The study “should be viewed with a giant dose of skepticism,” he said. “This appears to be a health study in search of a health problem.”

Europe banned U.S. and Canadian beef because of concern that the hormones could affect human health, setting off a trade dispute in which the U.S. responded with trade sanctions of its own. Though the World Trade Organization sided with the U.S. and Canada, Europe has persisted with the ban.

“I want to make sure that women don’t read this and take away a message that they shouldn’t eat meat while pregnant,” Swan said. “It doesn’t hurt to look for organic beef, and it’s very important pregnant women get enough protein.”

Source : www.bloomberg.com