Sperm counts in men have declined precipitously over the past four decades. A growing list of environmental factors has been implicated in this alarming phenomenon. Read on to learn about the environmental toxins and dietary factors that lower sperm count and how simple lifestyle changes can be used to improve male reproductive health and raise sperm count.
Why should we be concerned about low sperm counts?
New research indicates that sperm counts have declined by a shocking 59 percent over the course of the past four decades. Alarmingly, this decline shows no sign of stopping. (1) There are several reasons why we should be very concerned about rapidly sinking sperm counts. First and foremost, low sperm count is a major contributing factor in male infertility. Currently, studies suggest that 40 to 50 percent of infertility cases among couples are due to male infertility. (2) Infertility is a significant source of stress for couples and can have devastating effects on relationships, not to mention significant implications for the future of the human species.
A reduced sperm count is also associated with increased all-cause mortality and morbidity. Scientists believe that the relationship between sperm count, morbidity, and mortality is mediated by testosterone; adequate testosterone is required for sperm production and protects against cardiovascular disease, diabetes, and obesity, three leading causes of morbidity and mortality. Conversely, low testosterone is related to reduced semen quality and increases the risk of these chronic health conditions. (3) Finally, a low sperm count is associated with an increased risk of other male reproductive health problems, including testicular cancer. (4)
Decreased sperm count, therefore, has significant implications beyond fertility and may be an important indicator of health across a man’s lifespan. In order to protect the fertility of the human species and the long-term health of men, it is crucial that we uncover the underlying causes of declining sperm counts. A growing body of research indicates that environmental factors may lie at the root of this disturbing phenomenon.
Simple lifestyle changes that can improve male fertility.
Environmental factors affecting sperm count
A slew of environmental factors have been linked to impaired spermatogenesis and reduced sperm count, including endocrine-disrupting toxins, poor dietary habits, and the use of certain drugs. In order to protect male reproductive health and fertility, it is crucial that our male patients reduce their exposure to these harmful environmental factors.
Dietary exposure to pesticides has a detrimental effect on sperm count. A recent cross-sectional study involving 189 young men found that those who consumed fruits and vegetables with high pesticide residues had significantly lower sperm counts compared to men who consumed produce with lower pesticide residues. (5) Animal studies indicate that pesticides impair spermatogenesis by promoting oxidative stress, disrupting hormonal pathways, and inducing sperm DNA damage. (6) While individual phytochemicals in fruits and vegetables have been found to improve semen quality, the adverse effects of consuming pesticide residues on produce may outweigh the potential health benefits of phytochemicals.
In addition to pesticides, a handful of other endocrine-disrupting chemicals have been associated with lowered sperm counts. BPA, the ubiquitous estrogenic chemical found in plastics, receipts, and food packaging, causes errors in spermatogenesis that result in reduced sperm counts. (7, 8) While often promoted as a safe alternative to BPA-containing plastics, “BPA-free” alternatives may be equally harmful to the male reproductive system; in animal research, the BPA substitute bisphenol S has been found to induce apoptosis of germ cells, ultimately reducing germ cell counts. (9) Phthalates, a class of chemicals found in vinyl plastic and personal care products, lowers sperm counts by impairing enzymes involved in spermatogenesis. (10, 11) Polychlorinated biphenyls (PCBs), persistent environmental pollutants once used in transformers, hydraulic fluids, and building materials, reduce numbers of motile sperm. (12) Finally, men with high blood levels of perfluoroalkyl acids (PFAAs), a type of chemical found in non-stick cookware and water-repellent textiles, have demonstrated significantly reduced numbers of normal sperm compared to men with lower blood PFAA levels, suggesting that PFAAs disrupt spermatogenesis and alter sperm morphology. (13)
Circadian rhythm disruption
Circadian rhythms, the internal organization of biochemical processes in the body that regulates behavior and physiology, have a significant influence on male reproductive function. Animal studies indicate that genetically induced circadian rhythm disruption lowers sperm count by up to 70 percent. (14) In humans, circadian rhythm disruption may be induced by abnormal sleep schedules and exposure to blue light at night from electronic devices. In fact, preliminary human research suggests that shift workers, who have notoriously abnormal sleep schedules, have lower sperm counts compared to men who do not perform shift work. (15) While shift work is an extreme example of a circadian disruptor, other seemingly innocuous lifestyle habits, such as watching TV or reading on an iPad before bed, may also impair male reproductive function.
Diet has a significant impact on sperm quality. Consumption of a Western diet high in processed, sugar-laden foods is associated with a decreased sperm concentration and abnormal sperm morphology.(16) Furthermore, men who regularly consume soy, a common food in the Western diet, have decreased sperm concentrations relative to men who don’t consume soy foods. This effect may be due to the endocrine-disrupting impact of soy isoflavones on the male reproductive system. (17)
While the processed Western diet reduces sperm quality, consumption of a diet based on nutrient-dense whole foods such as vegetables, fruits, nuts, seeds, seafood, and clean meats has been associated with higher sperm quality. (18) Specific nutrients in a whole-foods diet, such as omega-3 fatty acids, vitamin E, vitamin C, beta-carotene, selenium, zinc, cryptoxanthin, lycopene, vitamin D, and folate have been found to individually improve semen quality parameters such as sperm concentration and motility by reducing sperm oxidative damage and inhibiting sperm DNA damage. (19)
Pharmaceutical and recreational drug use
Pharmaceutical and recreational drug may also reduce sperm quality and numbers. Specifically, the use of selective serotonin reuptake inhibitors (SSRIs) is associated with reduced sperm counts and abnormal sperm morphology. (20) The mechanisms behind this may be due to the spermicidal and DNA-damaging effects of SSRIs. In fact, fluoxetine has been found to exhibit spermicidal activity equivalent to nonoxynol-9 (N-9), a commercially available spermicide! (21)
Recreational drugs may be equally harmful to male fertility; men who use marijuana more than once per week have demonstrated a 29 percent lower sperm count compared to men who don’t use the drug. Tetrahydrocannabinol (THC), the chemical compound in marijuana that produces a high, may reduce sperm count by binding to CB1 receptor sperm cells, impairing spermatogenesis, sperm mitochondrial function, and sperm motility. (22)
A recent literature review examining the relationship between alcohol intake and semen quality found that high alcohol intake, defined as daily consumption of one or more alcoholic beverages, was associated with reduced sperm volume and abnormal sperm morphology. Frequent alcohol intake may adversely affect sperm parameters by reducing testosterone and increasing sperm DNA fragmentation. Interestingly, occasional alcohol intake does not appear to adversely impact sperm parameters. In fact, moderate consumption of beer and wine polyphenols may protect sperm from oxidative damage. (23) In this case, it appears that “the dose makes the poison.”
Lifestyle changes for increasing sperm count
Healthcare practitioners can make the following recommendations to their male patients to help them optimize their sperm counts:
- Eat a diet consisting of whole, nutrient-dense foods, and avoid soy as much as possible. Consumption of a healthy diet will ensure that sufficient nutrients are available to support spermatogenesis. Avoidance of soy eliminates a significant source of phytoestrogens, which can alter male hormonal balance and disrupt sperm production.
- Eat organic produce or choose fruits and vegetables low in pesticides. Don’t use pesticides at home for lawn care. This will reduce pesticide exposure, which impairs spermatogenesis. Check out the “Clean 15” and “Dirty Dozen” lists on Environmental Working Group’s website for information on pesticide levels in conventionally grown produce.
- Limit the consumption of canned foods (even ones labeled “BPA-free”), substitute plastic food containers with glass or stainless steel, and say “no” to receipts. This will reduce exposure to BPA.
- Choose organic, non-toxic skin care products. This will limit exposure to endocrine-disrupting phthalates.
- Use enameled cast iron or stainless-steel cookware instead of nonstick cookware. This will decrease exposure to PFAAs.
- Optimize circadian rhythms. This can be accomplished by getting plenty of sunlight during the day, avoiding blue light exposure from electronic devices at night, and sticking to a regular sleep schedule.
- Try red light therapy (also referred to as “low-level laser therapy”). Red light has been found to raise testosterone, which influences spermatogenesis, and improve sperm motility. (24, 25)
- Decrease use of alcohol and marijuana.
- Consider alternatives to SSRIs for the treatment of depression and anxiety.
Now I want to hear from you. Have you observed associations between environmental factors and reduced fertility among male patients in your practice? What interventions have you found helpful for supporting male reproductive health? Let me know in the comments below.