Pesticides in Your Food and Reduced Fertility

Key Takeaways From This Article:

• Some pesticides still in use in the United States have been banned in Europe and other parts of the world. Exposure to some of these pesticides has been linked to fertility issues, birth defects, cancer, and other conditions.
• Some fruits and vegetables are known to have higher pesticide residue levels than others. These fruits and vegetables, flagged by the Environmental Working Group as the “dirty dozen,” include: strawberries, spinach, kale, nectarines, apples, grapes, peaches, cherries, pears, tomatoes, celery, and potatoes.
• A recent Harvard study found that women undergoing fertility treatment who ate fruits and vegetables known for high pesticide residue levels had lower success rates in conceiving over women who ate fruits and vegetables known for having fewer pesticide residue levels.
• Eating a varied diet of fruits and vegetables is essential to good health and to the developing fetus. Women who are having fertility difficulties, might be sensitive to pesticides, and may want to choose organic produce or choose produce known to have lower pesticide residue levels.

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According to JAMA Internal Medicine, 90% of people in the U.S. have detectable levels of pesticides in their blood or urine. While these levels are not what toxicologists would consider “dangerous,” the question about whether any pesticide in a person’s system could have an impact on human health has remained open to study. A range of recent studies indicate that pesticide exposure is not without its consequences. For example, the International Journal of Environmental Research and Public Health notes that pesticide exposure has been linked to the development of breast cancer and prostate cancer, fertility issues, allergies, as well as intellectual impairment and impaired central nervous system functioning in children when they are exposed to pesticides in the womb. Alarmingly, many of the pesticides that are currently permitted in the U.S. have been banned or are being phased out in Europe, China, and Brazil (Europe, China, and Brazil are the three other major agricultural producers alongside the U.S.). The European Union has the most robust protections when it comes to pesticide restrictions, with the E.U. banning any pesticide known to have a carcinogen, reproductive toxin, or endocrine disruptor, according to the journal, Environmental Health. 

The reasons why the U.S. permits pesticides not permitted in other parts of the world involve the interests of major chemical companies pouring millions of dollars into lobbying efforts. The Nation reports that Dow Chemical spent $1.2 million lobbying in California alone. On the national level, these companies and their interests often forge close ties with congress and the EPA to undermine rules that would ban pesticides known to pose risks to human health. Chemical companies promote politicians friendly to their causes. Advocates for farm workers and consumers find themselves fighting an uphill political battle against the pesticide companies, an industry that has the money to fight regulations. Because the U.S. permits the use of pesticides not permitted in other parts of the world, it is ultimately up to each person to decide whether they want to switch to organic foods altogether, or avoid fruits and vegetables known to have been exposed to higher pesticide residues. For vulnerable populations like pregnant women and women looking to become pregnant, these issues are even more urgent.

Known Pesticide Risks on Human Health, Fertility, and Fetal Development

Pesticides can serve as endocrine disruptors (chemicals that can interfere with hormones or imitate hormones produced by the endocrine system), which can impact human health in a variety of ways. According to the National Institute of Environmental Health Sciences, endocrine disruptors can copy estrogens (female hormones), androgens (male hormones), and thyroid hormones. Endocrine disruptors can create problems for the developing fetus, leading to central nervous system issues and problems with intellectual development. Additionally, endocrine disruptors can block the way natural hormones are produced or controlled. Some individuals might be more sensitive to endocrine disruptors than others, but the result of exposure to these chemicals can include birth defects, fertility issues, cancer, and other health problems. Researchers writing for Current Opinion in Pediatrics found that babies exposed to certain types of pesticides while in the womb were more likely to have neurodevelopmental issues. According to the Journal of Agromedicine, men who were exposed to pesticides in agricultural work were found to have higher levels of sperm abnormalities and women had decreased fertility. Fetal exposure to pesticides was linked to birth defects, growth problems, neurobehavioral problems, and childhood leukemia. Endocrine disruptors can interfere with hormone production (like testosterone), can lead to poor semen quality in men, and fertility difficulties in women. 

In another study published in the European Journal of Epidemiology, male greenhouse workers exposed to high levels of pesticides took longer to conceive than a control group (one that didn’t work in a greenhouse). Finally, even living in a region known for its agricultural production can impact sperm quality. Research published in the International Journal of Andrology found that men in Missouri (a region of the U.S. known for its high agricultural production) had lower sperm quality and motility than men in other more urban areas, like New York and California. The researchers believed that the men may have become exposed to these higher levels of pesticides through groundwater contamination. Toxicology Letters further notes that the link between pesticide exposure and lower sperm quality is clear, with exposure to pesticides like DDT having estrogenic effects (increase in female sex hormones in men), damaged DNA, reduced sperm counts, and other hormonal changes that can impact male fertility.

What these studies have in common is that pesticide exposure is researched in the context of agricultural work and in the context of living in proximity to agricultural areas, where exposure to pesticides is higher. However, the big question remains: could eating fruits and vegetables that have been treated with pesticides have a similar impact on fetal development, fertility, and human health? In other words, can casual exposure to pesticides through our food affect our health? Because fruits and vegetables only contain residual amounts of pesticides, it has long been thought that the risk was low. 

Eating Fruits and Vegetables with High Pesticide Levels May Decrease Fertility in Some Women

 Now, a recent study performed by researchers at the Harvard T.H. Chan School of Public Health offers some preliminary answers to this key question. The researchers found that women who were undergoing fertility treatment who ate fruits and vegetables linked to higher pesticide residual levels had poorer reproductive outcomes than women who self-reported eating fruits and vegetables linked to lower pesticide residue levels. Researchers analyzed the diets of 325 women who were receiving assisted reproductive technologies. The types of vegetables and fruits they reported consuming were categorized as having high pesticide residue or low pesticide residue. Women who consumed fruits and vegetables with lower residue levels saw better reproductive outcomes.

This is the first study to indicate that pesticide residue on fruits and vegetables can have an impact on human health, particularly on human fertility and conception. What does this mean for you if you are trying to conceive? And what does this research mean for you if you are thinking of undergoing assisted reproductive technologies (ART)?

The study certainly raises some alarm about the risk of pesticide exposure in women looking to conceive, pregnant women, and babies. However, women looking to conceive and those looking to undergo fertility treatment shouldn’t avoid fruits and vegetables altogether, because these foods contain important nutrients needed for a growing and developing baby. The Environmental Working Group, an organization that analyzes USDA testing to determine which fruits and vegetables might have the highest levels of pesticide residue, notes that fresh fruits and vegetables are essential to a healthy diet, and that eating organic or conventional fresh fruits and vegetables is important to human health and to the developing fetus. So, even if a person chose to eat fruits and vegetables known to have higher residue levels, these levels would still not expose someone to levels that are deemed dangerous. 

The Harvard study (which found a link between higher pesticide residue fruits and vegetables and lower fertility) focused its study on a group of women who were having trouble conceiving and who were undergoing ART; this group may already be sensitive to certain endocrine disruptors. So, while the study might offer some nutritional guidance for those undergoing fertility treatment or for those who are facing fertility difficulties, it is too early to tell if the study can offer generalized guidelines for all women looking to conceive.

However, for couples who may be having trouble conceiving, or for those who may have sensitivities to chemicals and pesticides, when it comes to fruits and vegetables known to have higher pesticide residue, choosing organic may be best. If a person has food restrictions due to food sensitivities or medical reasons, supplementing one’s diet with a wellness supplement or daily supplement can also be beneficial.

Which Fruits and Vegetables Have the Highest Levels of Pesticide Residue?

The Environmental Working Group releases its “dirty dozen” list every year, which is a list of the fruits and vegetables found to have the highest levels of pesticide residue. The organization looks at USDA testing for pesticide residue levels, and lists the fruits and vegetables most likely to have the highest concentration of pesticide residue. Kale and spinach were identified as having the highest pesticide residue over any other crop tested (anywhere from 1.1 to 1.8 times the pesticide residue of any other crop). 90 percent of strawberries, apples, cherries, and nectarines tested positive for having residue of two or more pesticides. Different samples of kale showed traces of up to 18 different pesticides. 

For women undergoing fertility treatment, organic might be the best option when it comes to eating strawberries, spinach, kale, nectarines, apples, and grapes. On the other hand, fresh fruits and vegetables like avocados, corn, pineapples, onions, papayas, and eggplants were identified as having the lowest pesticide residues. So, if you can’t afford organic, and are struggling to conceive, it can’t hurt to choose these options.

Women who may be sensitive to endocrine disruptors and those undergoing fertility treatments may choose to eat organic fruits and vegetables, or conventional fruits and vegetables with lower pesticide residue levels, paired with a daily wellness supplement.

How You Can Limit Your Exposure to Pesticide Residue?

Finally, according to the National Pesticide Information Center, to avoid exposure to pesticide residue, thoroughly wash all fruits and vegetables under running water, and thoroughly dry fruits and vegetables before eating. Eating a variety of fruits and vegetables is also a good idea, because this lowers the risk that you might be eating one type of vegetable known to have high residue levels. Throwing away the outer layer of leafy greens rather than eating them can also protect you from pesticide residue exposure. Finally, recognize the Environmental Working Group’s “dirty dozen” fruits and vegetables known for high pesticide residue levels, and choose organic or limit your exposure.

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