High levels of lead could impede sperm, causing male infertility

Unexplained male infertility is responsible for about one-fourth of cases in which couples can’t conceive. Now U.S. researchers have narrowed the search for a cause with the discovery of lead’s toxic affects on sperm. An analysis of sperm from 127 men whose partners were planning to have in-vitro fertilization found that about 30% had high lead levels. These men had fewer receptors for mannose, a sugar that coats the egg, than men with lower levels of lead. (Normally, receptors on the head of the sperm bind to mannose, which allows the sperm to penetrate the egg.) High lead levels can also cause the binding reaction to happen prematurely and may lower the sperm count as well.

The high lead levels were unexpected, considering that none of the men was exposed to lead on the job, reports lead author Susan Benoff, director of the Fertility Research Laboratories at the North Shore-Long Island Jewish Research Institute in Manhasset, N.Y.

Potential sources of lead are vitamin and mineral supplements, alcohol and cigarettes. Lack of exercise and a high-fat diet are possibilities, because lead levels rise with decreased physical activity.

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Dianne Partie Lange