Study Links Beef to Lower Sperm Count
Beef Industry Disputes Results Showing Beef Diet of Pregnant Moms Affects Sons
March 27, 2007 -- A new study suggests that men whose mothers ate lots of beef during pregnancy may have lower sperm counts than other men.
The researchers say residues of hormones given to beef to promote growth may be a factor, but that's not certain.
The beef industry disputes that theory.
"Nothing from this study changes the fact that during pregnancy, naturally nutrient-rich beef is a vital part of a healthy, wholesome diet for a mother and her child," Mary K. Young, MS, RD, tells WebMD in an emailed statement.
Young is the executive director of nutrition for the National Cattlemen's Beef Association (NCBA).
About the Study
The researchers included Shanna Swan, PhD, director of the Center for Reproductive Epidemiology at the University of Rochester Medical Center in Rochester, N.Y.
Their study appears in Human Reproduction.
Swan and colleagues studied 387 men (born between 1949 and 1983) whose partners were pregnant. The men provided semen samples and completed surveys about their diet and other lifestyle habits.
The men were also instructed to ask their mothers what they had eaten while pregnant with them decades earlier.
The moms reported eating four weekly servings of beef during pregnancy, on average.
Fifty-one moms reported eating beef more than seven times per week during pregnancy. The average sperm concentration for their adult sons was 24% lower than men whose moms ate beef less often during pregnancy, the study shows.
In addition, about 17% of men whose moms ate beef more than seven times weekly during pregnancy had sperm concentrations in the "subfertile" range, the researchers note.
However, all of the men fathered children without medical treatment, according to the study.
The study shows no links between other foods eaten during pregnancy and the men's sperm count. In addition, the men's beef intake as adults wasn't associated with sperm count.
Hormones have long been administered to U.S. beef cattle to promote cattle growth, the researchers note.
Traces of such hormones may be more likely to affect fetuses than adults, Swan's team suggests.