A study has found a link between increased consumption of fruit and vegetables containing high levels of pesticide residues and reduced sperm count and quality.
In the 1970’s it was observed that there was an increased number of men with infertility who worked at pesticide factories, which seemed to be associated with the length of time the men worked at the factories. Additionally, pesticide exposure has been linked with changes in hormone levels, which may affect hormones and reproductive biology. Researchers from the Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA, therefore set out to investigate the link between pesticide exposure through food and sperm quality. The study specifically looked at the link between pesticide residue present on consumed fruit and vegetables, and sperm quality in men who were attending a fertility clinic.
Participants were recruited from the Environment and Reproductive Health Study that began in 2006 at Massachusetts General Hospital Fertility Center, Boston, MA, USA. Men who were recruited for the study filled out a diet assessment food frequency questionnaire. A total of 155 men were included in the analysis.
In order to assess the association between pesticide exposure and semen quality, researchers developed a classification system whereby fruits and vegetables were categorized in to ‘high’ versus ‘low-to-moderate’ pesticide residue groups. The classification system was based on data obtained from the United States Department of Agriculture Pesticide Data Program. A total of 14 fruits and vegetables were classified as ‘high pesticide residue’ produce, and 21 classified as ‘low-to-moderate pesticide residue’ produce.
The results of the study showed that total fruit and vegetable intake was not associated with semen quality, however, there was an inverse association between the consumption of the ‘high pesticide residue’ produce and semen quality. That is, increased consumption of ‘high pesticide residue’ fruit and vegetables was associated with reduced quality semen. The 25% of men with the highest intake of pesticide residue produce had a sperm count that was reduced by 49%, with a 32% reduction in normal-looking sperm, and 29% reduced ejaculate volume when compared with the men who had the lowest intake of pesticide residue produce. While there was an inverse relationship between high pesticide consumption and low sperm count and quality, there was a positive association between consumption of ‘low-to-moderate pesticide residue’ produce and sperm quality. Overall, the data suggests that dietary exposure to pesticides, via fruit and vegetables, which is the primary source of non-work-related pesticide exposure, negatively affects sperm count and quality.
Pesticides have been shown to have ‘endocrine disrupting’ activity, that is, they interfere with hormonal pathways in the human body. In this way they may have an effect on sperm production. Alternatively, the authors suggest that certain pesticides can produce free radicals, inducing oxidative stress within cells, ultimately resulting in a reduction of sperm quantity and quality. In this study, however, the researchers did not specifically distinguish between types of pesticides that were consumed, and therefore the exact mechanisms that caused reduction in sperm quality remain unknown.
Chiu, YH, Afeiche, MC, Gaskins, AJ, Williams, PI, Petrozza, JC, Tanrikut, C, Hauser, R, Chavarro, JE. “Fruit and vegetable intake and their pesticide residues in relation to semen quality among men from a fertility clinic” Human Reproduction doi: 10.1093/humrep/dev064
Image courtesy of dan at FreeDigitalPhotos.net
Written by Deborah Tallarigo, PhD