In October 2020 the Lancet published an analysis of the Global Burden of Disease Study (2019), confirming an ongoing decline in global fertility rates over at least the past 20 years. Funded by the Gates Foundation, this analysis found that half of all countries/territories had “below replacement” fertility rates, and 88% of the 204 regions included witnessed a decrease over the last 10 years. This is consistent with the decline reported in the US; in 2019 the fertility rate had declined 2% from just the previous year, setting another record low.
Parallel to this disturbing trend is a long-standing decline in sperm count; a 50-60% decline in sperm count between 1973 to 2011 among unselected men in North America, Europe, Australia and New Zealand was documented in 2017, with an annual decline of ~1.5%. It is important to mention that if the trend continues, the mean sperm count will approach zero by 2045, and furthermore, the authors suggest this decline is the “canary in the coal mine,” as dropping sperm counts are associated with a variety of negative trends, including fairly dramatic increases in morbidity and mortality.
The Elephant in the Room
Although declining fertility is multifactorial, with contributions from poor diet, smoking, obesity, lack of exercise, etc., environmental pollutants seem to be the elephant in the room. In 2018, a nationwide study including nearly 30 million births in the US was published, finding roughly 70,000 less births per year from the effects of air pollution alone (pre-gestational exposure to PM2.5 were the primary culprit).
Toxic metals are also certain to impair fertility; data from the US NHANES (National Health and Nutrition Examination Surveys) suggest both lead and cadmium increase the likelihood of infertility among women at surprisingly common exposure levels. For example, over a 5-fold increased risk for infertility was documented among women in the 2nd and 3rd tertiles of lead exposure; the 2nd tertile included women with blood lead levels of only 0.41–0.62 µg/dL. A case control study in China found a steady increase for infertility among men exposed to relatively low levels of arsenic; men in the highest quartile had over a 36-fold adjusted increase in risk for infertility (and an 8-fold higher risk in only the 2nd quartile).
Unfortunately, this is only scratching the surface, as the list of endocrine disruptors to which we have regular and combined exposure is nearly endless, including plasticizers (such as bisphenol A (BPA) and phthalates), pesticides, perfluorinated compounds, flame retardants, PCBs, and other persistent organic pollutants. The concern that BPA may impair fertility seemed justified, yet replacing this with bisphenol S (BPS) (which degrades more slowly and is more slowly metabolized) is a typical example of both how short-sighted this industry is and how rapidly widespread exposure occurs to new compounds; in a cross-sectional analysis of men seeking infertility assistance, BPS was detected in 76% of samples, and it was associated with lower motility, total sperm count, volume, and other semen parameters, particularly among obese men. Thus, we have frequent exposure to a potentially problematic new compound, which persists longer than the toxin it was used to replace.
The soup of chemicals throughout our bodies does not just affect fertility, but many outcomes related to reproductive health and childhood as recently cited in the Lancet; Diabetes & Endocrinology, including birth weight, IQ, testicular cancer, fibroids, attention deficit disorders, preterm birth, and reduced anogenital distance among male babies (an indication of less exposure to testosterone).
Action Steps
Given this concerning level of exposure, what actions can a health practitioner take? Initial steps include educating patients about lifestyle changes they can take to reduce their chemical burden, and assessing toxin exposure, particularly if they are considering having children or are struggling with infertility. Many couples are diagnosed with “idiopathic” infertility after more obvious causes are ruled out, but lab work for toxin exposure is not routinely done, and should be. Perhaps just as importantly, the timing of exposure may be more important than the total amount of exposure, and helping patients reduce their chemical burden before conception may protect fetuses when they are the most susceptible.
While a more complete protocol may be included in a future blog, in general, avoiding known sources of exposure and consuming an antioxidant and plant-rich diet with low chemical residues can lessen the harmful impact of environmental toxins. A number of specific dietary and nutraceutical interventions may also help improve fertility; for men, adding more nuts to the diet, supplementing with CoQ10, lycopene, and other antioxidants such as selenium and N-acetylcysteine appear to improve markers of fertility. N-acetylcysteine may also mitigate the effects of some toxins, such as BPA, and improve fertility in both men and women. Similarly, CoQ10 and melatonin may have broad antioxidant benefits, and supplementation with additional antioxidants should be considered.
An excellent resource with additional steps for reducing exposure (e.g., an organic diet, avoiding plastic, etc.) and a closer examination of the problem is a new book titled “Count Down, How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race,” published February 2021 by Shanna Swan, PhD.
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