The global rise in human infertility due to environmental toxicants is gaining attention in both scientific research as well as mainstream media. As the number of toxic synthetic chemical production increases (currently over 80,000) at an alarming rate for use in commerce, both female and male fertility declines. In North America alone, approximately 1 in 7 to 10 couples have extreme difficulty conceiving. Research is transparent that pollutants and metals in the air, water, food, soil, and beauty products are causing fertility complications by disrupting endocrine system homeostasis, damaging the female and male reproductive systems, and crippling fetal growth and survival.
Out of all the fertility disruptors, the worst offenders according to a recent review are bisphenol A (BPA), organochlorine compounds such as dioxins and polychlorinated biphenyls (PCBs), and organophosphate pesticides and herbicides. BPA and phthalates are widely used endocrine-disrupting chemicals in the plastics and pesticide industries, consequently ubiquitous in the environment. An in vitro study demonstrated that exposure to BPA in human and rodent fetal testes significantly inhibited testosterone production. The primary cause of endocrine disruption leading to infertility is the manifestation of conditions associated with blood sugar dysregulation such as metabolic syndrome, diabetes, and PCOS.
In a prospective cohort study, urinary phthalate metabolites were detected in 62-99% of pregnant women during their first trimester and those who reported having a history of infertility had higher concentrations than those who reported no history of infertility or who used artificial reproductive technologies. Prenatal exposures are linked with ovarian and follicular dysfunction, anovulation, increased risk of nonviable pregnancies, labor timing variations, and neurobehavioral changes in infants and children. In males, phthalates demonstrate anti-androgenic activity and may disturb sex organ formation during development and damage DNA in sperm.
According to a study examining the association between phthalate metabolite concentrations in pregnant women and the intake of food, diet is a major source of phthalate exposure - an estimated 90% - mostly from the food packaging and phthalate-containing materials used in food processing. Furthermore, the same study concluded that consuming more homegrown or whole foods, limiting frozen vegetable and fruit intake and using more eco-friendly, chemical-free household and personal care products resulted in lower levels of urinary phthalate metabolites.
Furthermore, a decline in fertility is correlated with increased use and exposure to pesticides and herbicides. In the United States alone, nearly 1 billion pounds of chemicals are sprayed on fruits, vegetables, and nuts each year. Dicamba, one of the worst known pesticides among many others, caused nearly a 50% decrease in fertility, and glyphosate (recently shown to be a carcinogen) reduced fertility by 39%. Compared to men with the lowest intake of fruits and vegetables with high pesticide-residues, men who consumed the most had nearly 50% lower total sperm count. Animal models exposed to glyphosate showed an increase in testicular oxidative stress and DNA damage, as well as a decrease in sperm motility, sperm membrane integrity.
Among adult men who reported infertility, nearly 55% were exposed to environmental or occupational toxins, detecting 40% lead and 23% cadmium metals in seminal fluid. The men exposed to the heavy metals had a significantly lower sperm count, and sperm motility and viability compared to the non exposed group. The review we mention earlier in this article revealed that infertile couples had notably increased plasma levels of mercury compared with fertile controls, and that blood levels higher than 5 mcg/dL of lead doubles the risk of preterm delivery in women. Moreover, a meta-analysis elucidated that exposure to cigarette smoke is associated with lower sperm count, motility and morphology, and semen quality deterioration is more evident with moderate to heavy smokers.
Despite rapid elimination via urine and feces, constant and chronic exposures to these chemicals can cause a build-up in adipocytes and other tissues, which can consequently impair other organs’ detoxification and elimination abilities. Patients who are trying to conceive could benefit from avoiding exposure through lifestyle and dietary behavior modifications in order to improve fertility outcomes. The Environmental Working Group is a great resource for patients to learn more about alternatives to commonly used products and foods in order to limit toxin exposure for the betterment of their endocrine and reproductive health.