Men who ate fruits and vegetables with higher levels of pesticide residues, like strawberries, spinach, and peppers, had lower sperm count and a lower percentage of normal sperm than those who ate produce with lower residue levels, according to the new paper.
Studies have shown that consuming conventionally grown fruits and vegetables results in measurable pesticide levels in urine but associations between occupational and environmental exposure to pesticides and lower semen quality have been suspect. Lower semen quality in many developing nations has coincided with reduced pesticide levels rather than higher ones.
To make this correlation, the researchers used data from 155 men enrolled in the Environment and Reproductive Health (EARTH) study, an ongoing National Institute of Environmental Health Sciences-funded study at a fertility center in Boston. Data included 338 semen samples provided during 2007-2012 and validated survey information about participants' diets. The researchers classified fruits and vegetables according to whether they contained high amounts of pesticide residues (such as peppers, spinach, strawberries, apples, and pears) or low-to-moderate amounts (such as peas, beans, grapefruit, and onions), based on data from the U.S. Department of Agriculture Pesticide Data Program.
Pesticides include both the synthetic or organic kind.
They then adjusted for factors such as smoking and body mass index--both known to affect sperm quality--and looked for connections between the men's intake of produce with pesticide residue and the quality of their sperm.
The results showed that men who ate greater amounts of fruits and vegetables with higher levels of pesticide residue--more than 1.5 servings per day--had 49% lower sperm count and 32% lower percentage of normal sperm than men who ate the least amounts (less than 0.5 serving per day). They also had a lower sperm count, lower ejaculate volume, and lower percentage of normal sperm.
The men who ate the most fruits and vegetables with low-to-moderate levels of pesticide residue had a higher percentage of normal sperm compared with those who ate less fruits and vegetables with low-to-moderate levels.
"To our knowledge, this is the first report to link consumption of pesticide residues in fruits and vegetables, a primary exposure route for most people, to an adverse reproductive health outcome in humans," said Jorge Chavarro, assistant professor of nutrition and epidemiology at Harvard and the study's senior author. "These findings should not discourage the consumption of fruit and vegetables in general. In fact, we found that consuming more fruits and vegetables with low pesticide residues was beneficial. This suggests that implementing strategies specifically targeted at avoiding pesticide residues, such as consuming organically-grown produce or avoiding produce known to have large amounts of residues, may be the way to go."
That a nutritionist at Harvard believes that organic food does not use pesticides should be a hint for the National Institutes of Health that they might consider spending their money on food scholars that understand the basics of real-world agriculture.
Citation: "Fruit and vegetable intake and their pesticide residues in relation to semen quality among men from a fertility clinic," Y.H. Chiu, M.C. Afeiche, A.J. Gaskins, P.L. Williams, J.C. Petrozza, C. Tanrikut, R. Hauser, and J.E. Chavarro, Human Reproduction, March 30, 2015, doi:10.1093/humrep/dev064. Funding for the study came from the National Institute of Environmental Health Sciences, National Institutes of Health grants R01 ES009718, R01 ES022955, P30 ES000002, and P30 DK046200, and Ruth L. Kirschstein National Research Service Award T32 DK007703-16.