Worldwide: Sperm Counts Down

In the previous article, Dr Amin points out that sperm counts are declining and she offers some dietary advice to help men maximize their potential. In this article I will look at the world view and the consequences of this decline.

Julia Belluz writes for Vox that recent research suggests sperm counts are falling, with a 2017 study published in the journal Human Reproduction Update indicating sperm count “has halved in the West since the 1970s.” However, Belluz says, “Even the new low is still well within a normal range for sperm,” and while epidemiologists tend to be “generally more convinced by the sperm-pocalyse, the front-line practitioners treating men” are not. Belluz adds that the NIH in 2015 led research finding fertility rates “have fallen dramatically over the past half-century” while fecundity rates have not. However, Stuart Moss, Director of Male Reproductive Health at National Institute of Child Health and Human Development, acknowledged, “It’s clear from a number of epidemiological studies that a male’s fertility can be a determinant of his overall health. So a low sperm count is troubling from a number of areas and could be a biomarker for poor health in general.”

In the press release for the study, the authors declared a sperm-centric public health emergency. “This study is an urgent wake-up call for researchers and health authorities around the world to investigate the causes of the sharp ongoing drop in sperm count,” said Dr. Hagai Levine, the study’s lead author, from the Hebrew University of Jerusalem’s Faculty of Medicine, “with the goal of prevention.”

Scientists’ best guess is that there are a number of changes in how we live that haven’t been good for sperm. Being overweight or obese is associated with poorer semen quality and we’ve seen rates of overweight and obesity soar over the past several decades. Smoking, stress, sedentary lifestyles, and alcohol and drug use are all also implicated. But a major factor and one that’s surprisingly non-controversial among scientists is thought to be the rise of the 20th-century chemical industry.

Much of the food we eat and the everyday objects we use these days are stored in or made using plastics, which contain man-made chemicals. These chemicals are also present in our creams and cosmetics, our household cleaning products, and our drugs and medical devices. They leach into our food and water, into the environment, and into our bodies.

Most are thought to be harmless. But some can mess with our hormones as endocrine disruptors in ways that hamper our reproductive capacity.

Specifically, chemicals like BPA, BPS, and phthalates are known to mimic hormones like estrogen, interfere with important hormone pathways in the thyroid gland, and inhibit the effects of testosterone. And even though many companies are now manufacturing phthalate- or BPA-free products, scientists are concerned about substitute chemicals, since they’re often functionally similar to the chemicals of concern.

What this means for men’s sperm counts: Men who are exposed to hormone disruptors in utero have been shown to produce less testosterone and less sperm, and have other physiological changes associated with, as GQ’s Halpern put it, being “less male.”

But what can a man do about this? Besides having regular sex, there are other important things men can do to improve their semen quality and chances of fathering a child:

Maintain a healthy weight: Being significantly overweight and obese can mess with hormones, like testosterone, that are important for reproductive health.

Don’t smoke, do drugs, or drink too much: Smoking is heavily associated with infertility. There’s more limited — but still concerning — evidence that using marijuana and drinking heavily hampers men’s fertility, too.

Stay away from hot tubs and saunas: Exposing the testicles to hot temperatures is widely accepted to decrease sperm production. The fertility experts I spoke to suggested heated seats in cars, sitting for long periods of time, and holding laptops on the groin can have similar effects.

Consider boxers: There’s some evidence that men who wear boxers have higher sperm concentrations than brief-wearers.

Exercise and eat a healthy diet: Exercise improves blood testosterone and sperm production. A Mediterranean-style diet — favoring fresh fruits and vegetables, seafood, poultry, and whole grain — is associated with better semen quality in men.

For specific dietary information please see Dr. Amin’s previous post.

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