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Reviewed research
Authors Chiu YH, Afeiche MC, Gaskins AJ, et al.
Review Date May 2015
Citation Human Reproduction 2015;.30(6): 1342 –1351
Background
Infertility affects an estimated 14% of all couples, and in 20-30% of infertility cases, the sole cause is attributed to male factor infertility. Research has revealed an association between pesticide exposures, whether occupational or environmental, and decreased semen quality parameters. Despite conventionally grown fruits and vegetables being a major source of non-occupational pesticide exposure, few studies have examined the effect of this on male reproductive health.
Aim
To investigate the association of dietary pesticide exposure with semen quality.
Methods
This is a sub-study of the Environment and Reproductive Health (EARTH) Study. Men were eligible if they were aged 18-55 years, without history of vasectomy, and in a couple planning to use their own gametes for fertility treatment. For this sub-study, men were included if they completed the food frequency questionnaire (FFQ) component of the main study and if they provided semen samples up to 10 months after this. The 131-item FFQ is a validated measure of self-reported food, beverage and supplement consumption. Fruits and vegetables were categorised into pesticide levels using data from the annual United States Department of Agriculture Pesticide Data Program. Sperm concentration and motility were evaluated by computer-aided semen analysis (CASA). Sperm motility was classified using WHO criteria and sperm morphology was determined using Kruger’s strict criteria. Linear mixed models were used to analyse associations between dietary pesticide exposure and sperm parameters
Results
Included in the analysis were 155 men who contributed 338 semen samples; 57 (37%) men included one sample and the remainder two or more. The median age was 36 years and most men were Caucasian (83%) and non-smokers (63%); 52% were overweight and 18% were obese.
Forty-six percent of men had at least one semen analysis with a parameter below the WHO lower reference limits. Men had an average of 0.9 servings/day of high pesticide produce and 2.3 servings/day of low-moderate pesticide produce. Men who consumed more high pesticide produce tended to be older, and have high caloric intake and physical activity.
Total fruit and vegetable intake was not associated with semen quality. However, there was an inverse relationship between intake of high pesticide produce and semen quality. On average, men in the highest quartile of high pesticide produce consumption had 49% lower total sperm count, 32% fewer morphologically normal sperm and 29% less ejaculate volume. High pesticide produce consumption was also significantly associated with lower total motile count and lower total normal count.
Conclusion
This study evaluated the association between dietary pesticide exposure and semen quality. The authors found that consumption of high pesticide fruit and vegetables was inversely associated with total sperm count, ejaculate volume and percentage of morphologically normal sperm. These findings suggest that dietary exposure to pesticides may impact semen quality in men. This is consistent with a moderate body of research that has consistently demonstrated occupational and environmental pesticide exposure is associated with reduced semen quality.
Points to Note
- Male infertility is the sole factor in many infertility cases. Previous research suggests that pesticide exposure is associated with reduced semen quality. Few studies have examined the effect of dietary pesticide exposure on semen quality.
- The findings of this study revealed that consumption of high pesticide fruit and vegetables was inversely associated with total sperm count, ejaculate volume and percentage of morphologically normal sperm.
- This study faced limitations such as only assessing men’s fruit and vegetable consumption at one time point (when it could have changed over time) and the inability of the FFQ to distinguish between conventionally and organically grown vegetables. Even so, such limitations suggest the observed effects may be an underestimation.
- This study was observational in design; further research with intervention studies is needed to explain better the observed relationship between dietary pesticide intake and semen quality. Future research should also include a more diverse sample beyond Caucasian men accessing fertility services to increase the generalisability of results.
- There is an increasing body of research that suggests pesticide exposure is associated with poor reproductive health in men and women; public policy may need to be updated to reflect this research to improve population health.
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