Eating fruits and vegetables treated with pesticides may be linked to lower sperm counts in men and a lower percentage of normal sperm, researchers at Harvard University suggest.
Scientists at the University's T.H. Chan School of Public Health say their study is the first to link the pesticides found in fruits and vegetables to reproductive difficulties.
Although their study could not establish a direct cause and effect link between pesticides and problems seen in sperm samples from 155 men, the results clearly "suggest that exposure to pesticides used in agricultural production through diet may be sufficient to affect spermatogenesis in humans," the researchers said in a study published in the journal Human Reproduction.
The potential for an impact on sperm production from pesticides has long been suspected among men who work with the chemicals and who are subject to heavy exposure to them in the environment, the researchers say.
The researchers studied sperm samples and questionnaire answers from 155 men enrolled in the Environment and Reproductive Health study in Boston, an ongoing research project funded by the National Institute of Environmental Health Sciences.
The men who consumed those fruits and vegetables known to carry the highest levels of pesticides had sperm counts 50 percent lower than those who ate the least of those items, the researchers found.
The highest levels of pesticides are normally found in strawberries, apples, spinach and celery, says the nonprofit consumer health organization Environmental Working Group.
Lowest levels are normally seen in sweet corn, avocados and pineapples, it says.
Those in the study who ate the foods highest in pesticides also displayed 32 percent more abnormally shaped sperm, says study co-author Dr. Jorge Chavarro, an epidemiologist at the Harvard School of Public Health.
"I think this raises a lot more questions," he says. "It was actually very surprising to me ... that we were able to identify such a strong association, which to me says there is something going on there."
What the study could not reveal, Chavarro says, is whether it's a single pesticide or chemical involved, or some combination men are exposed to.
"One of the limitations of this study is that we cannot link exposure to any one pesticide. It may be linking back to a pesticide mixture, which is more difficult to assess," he says.
People shouldn't stop consuming fruits or vegetables based on the findings, the researchers emphasize, noting that both are considered vital parts of a healthy diet.
Chavarro does recommend people consider organic fruits and vegetables, or at least those varieties known to harbor less of the agricultural chemicals.
