As most men know by now, sperm counts have been plummeting for the past 50 years. According to the World Health Organization (WHO), just five to 15 percent of human sperm today qualifies as "normal," and is only found in men who are young and healthy. In contrast, over 90 percent of sperm produced by a ram, bull, or common lab rat are considered viable.
The million-dollar question, of course, is why. While most experts agree that the downward trend is not the result of a single health hazard, scientists have only recently started to hone in on some of the environmental and lifestyle choices that may be contributing to our steadily shrinking seed. Here's a look at some of the more recent studies.
1. You Are What You Eat
According to a study published this week in the journal Human Reproduction, diets high in saturated fats are bad for both waistlines and sperm count. Researchers found that subjects who ate more saturated fat had lower sperm count and concentration, while diets high in omega-3s were associated with better-quality semen and sperm cells with a better size and shape.
The study's lead author, Dr. Jill Attaman, an endocrinologist at Dartmouth-Hitchcock Medical Center, said the study could lead to a better understanding of how lifestyle factors affect male fertility. "There are few clearly identifiable lifestyle modifications that can be made to optimize natural fertility, especially for males,"said Attaman to ABC News. "This is the first report of a relation between specific dietary fats and semen quality."
2. Remove Cell Phones from Pockets
If keeping a metal slab of electromagnetic radiation near your chestnuts doesn't seem like a smart idea, you're right. According to an Italian study published in the Journal of Andrology, researchers have found that the radio-frequency electromagnetic radiation (RF-EMR) emitted by cell phones can decrease sperm count and damage sperm quality.
Specifically, the study found decreased concentration, mobility, and health of sperm when comparing sperm concentrations for men who held their cell phones in their front pants pocket versus those who didn't. Said Dr. Joel Moskowitz, director of the Center for Family and Community Health at the University of California at Berkeley, to CNET: "If more research is done, and we have more solid results, consumers could be presented with a choice. There might be phones or cell services that have less impact on our reproductive organs than others."
3. Stay Fit—But Don't Overdo It
According to a 2008 study, obese men may have lower-quality sperm than men who are of normal weight. Said Ghiyath Shayeb, the study’s lead researcher at the University of Aberdeen, to the AP:."There is a very long list of health hazards from being overweight. Now we can add poor semen quality to the list." Not only did larger men have a 60 percent higher chance of having a low volume of semen, they also had a 40 percent higher chance of having some sperm abnormalities. Neil McClure, professor of obstetrics and gynecology at Queen’s University in Belfast, agreed: “Male fitness and health are clearly linked to a man’s fertility."
That said, it's best to keep fit in moderation when it comes to healthy sperm. According to Shayeb's research, underweight men were just as likely to have abnormal sperm counts as overweight men. And in other studies, long-distance runners who ran more than 100 miles a week and cyclists who rode more than 50 miles per week were found to have decreased sperm counts, most likely due to lower testosterone levels.
4. Loosen Up
Boxers or briefs? When it comes to sperm health, the answer is clear: in order for testes to produce high quality sperm, their temperature must be slightly lower than the body's core temperature. Explains Celia E. Dominguez, reproductive endocrinologist at the Center for Reproductive Medicine at Emory University School of Medicine, to WebMD: "That is why [testes] are located outside of the body. Testes were made to be out in the breeze."
In fact, its best to avoid letting your package come in contact with high temperatures altogether. Saunas, hot baths, and even tight pants can impact the health of sperm by cooking them out of commission. Said Amos Grunebaum, MD, director of clinical maternal-fetal medicine at the New York Hospital-Cornell Weill Medical College, to WebMD: "When you're at home, take off your pants. It will not only help reduce testes temperature, but it might also turn her on."
5. It All Starts in the Womb
Increasingly, studies are showing that future sperm health can be impacted even before your baby is born. According to a 2007 study, women who ate a lot of beef during their pregnancies had sons with 25 percent lower sperm counts and three times the normal risk of fertility problems (most likely due to pesticides or the use of anabolic steroids used to fatten up cattle). In another study, researchers found that men who smoked in adulthood reduced their sperm count by a modest 15 percent, reversible if they quit. In contrast, men whose mothers smoked during pregnancy demonstrated a 40 percent decrease in sperm count that was mostly irreversible.
According to Professor Richard Sharpe, fertility research expert at the Medical Research Council, the infrastructure for sperm production is laid down during the final trimester of gestation and just after birth. Anything that interferes with testicular health during that period will have permanent consequences on future fertility. "Maternal-lifestyle factors in pregnancy can have quite substantial effects on sperm counts in sons in adulthood," said Sharpe to The Independent, "and the most logical mechanism by which this could occur is via reducing the number of Sertoli cells [which make and protect sperm cells]".