Population-based clinical research has uncovered the troubling observation that male fertility appears to be slowly and steadily declining over the past 50 years. This trend appears to be clearest and most pronounced in Western geographic areas like North America, Europe and Australia. Total sperm counts amongst men from these areas have declined by almost 60% since 1973. Thinking about how Western populations differ from the rest of the world offers scientists hints about the underlying problem and how we might be able to reverse this alarming trend.
One possible explanation for declining male fertility is the ever-increasing percentage of men that are overweight or obese. Worldwide rates of obesity have tripled since 1975, with Western nations such as the United States and Australia unfortunately leading the way. Obesity alters male reproductive hormones, increases sperm oxidative stress and inflammation, and is clearly associated with poor sperm quality. Dietary and nutritional factors outside of obesity may also be implicated. Western-style diets with high intake of processed meats, high-fat dairy products, and sugars have been linked with abnormalities in sperm count, motility, and morphology. In contrast, clinical studies have shown that diets high in fish, whole grains, fruits and vegetables are associated with better sperm quality. The high rates of chronic diseases such as diabetes and hypertension in Western countries may also be contributing to declining fertility. Emerging data have clearly demonstrated relationships between overall and reproductive health in men.
Certain environmental toxins that have become more prevalent over the past half century are also thought to be implicated in declining male fertility throughout the world. The two most implicated environmental toxins are bisphenol A (BPA) and phthalates. BPA is used in plastic manufacturing and is found in hard, clear plastics used in water bottles, food containers, and some sports equipment. It can alter hormone signaling and has been linked to abnormal semen quality in numerous studies. Phthalates are chemicals used to manufacture hundreds of products that range from plastic toys to medications to perfumes. Phthalates appear to exert negative effects on sperm in several different ways and have been associated with sperm abnormalities in numerous animal and human studies.
Fortunately, the decline in sperm quality observed over the past 50 years has been mild. So far, we have not seen a significant impact on fertility rates amongst couples trying to conceive. The signal, however, is certainly alarming and warrants a response from men across the globe. What can men do to preserve male reproductive health? The call to action is actually very simple – get healthy! Individual level changes focused on weight loss, better eating, and environmental toxin avoidance won’t completely reverse the decline that we have seen in male fertility over the past 50 years. But proactive personal action can absolutely make a difference in your own sperm quality. Don’t wait to work on your reproductive health – the human race needs you now before it is too late…
