A new study has found a potentially harmful link between eating fruits and vegetables high in pesticides and having lower reproductive rates.
In the report, published in JAMA Internal Medicine, scientists studied 325 women who were using assisted reproductive technologies to get pregnant. They were part of the Environment and Reproductive Health (EARTH) study, which was designed to measure factors that can affect reproductive success. The women in the study filled out detailed questionnaires about their diet, along with other factors that can affect IVF outcomes, like their age, weight and history of pregnancy and live births.
Senior investigator Dr. Jorge Chavarro, an associate professor of nutrition and epidemiology at Harvard T. H. Chan School of Public Health, and his colleagues then matched the dietary responses with a U.S. government database of average pesticide residues on fresh fruit and vegetables to calculate a measure of the amount of pesticides the women were exposed to from their diet. Certain fruits and vegetables, such as strawberries, spinach and peppers, tend to consistently rank high on pesticide residues, while others, like peas and avocados, rank lower.
Women with high exposure were eating more than two servings of high-pesticide fruits or vegetables a day, compared to women in the lowest exposure group, who ate one serving of high pesticide fruits and vegetables daily on average. Women who had the highest pesticide exposure were 18% less likely to get pregnant than women with the lowest exposure, and 26% less likely to have a live birth.
“I was always skeptical that pesticide residues in foods would have any impact on health whatsoever,” says Chavarro. “So when we started doing this work a couple of years ago, I thought we were not going to find anything. I was surprised to see anything as far as health outcomes are concerned.”
The results only associate a higher measure of pesticides residues with lower IVF success rates; the findings do not establish that pesticide exposure through the diet causes poor reproductive health. But the results suggest that the amount of pesticides women are exposed to may be one factor that could affect whether they are able to get pregnant and carry a baby full term using IVF.
When the researchers modeled the effect of swapping one high-pesticide fruit or vegetable a day for a low-pesticide one, they found 79% higher odds of pregnancy and 88% higher odds of a live birth.
The study is the first to look closely at the role that pesticides people ingest through their food may have on reproduction. Animal studies have shown that when rodents are exposed to pesticides in the diet, they have higher rates of miscarriage and fewer live pups.
Chavarro says the findings should be the first step toward a better understanding of how pesticides in food affect people’s health. More research needs to be done to confirm the association with pesticide residues, and Chavarro expects to expand the work to look at other health outcomes, such as chronic diseases like cancer.
For now, he says it doesn’t hurt to consider eating organic fruits and vegetables that may have fewer pesticide residues, and consulting environmental groups and government websites for produce that tends to have higher residues than others. “I am now more willing to buy organic apples than I was a few months ago,” he says.