Pesticides used in our homes and gardens and sprayed on the food we eat are contributing to a dramatic decline in sperm counts among men around the world, according to a new analysis of studies conducted over the past 50 years.
“Over 50 years, sperm concentration has dropped by about 50 percent worldwide,” said study lead author Melissa Perry, dean of the School of Public Health at George Mason University in Fairfax, Virginia.
“What we don’t know is the culprit,” Perry said. “Although there are likely many other contributing causes, our study demonstrates a strong association between two common insecticides — organophosphates and N-methyl carbamates — and declining sperm concentration.”
Widely used pesticides
One of the most widely used compounds in the world, organophosphates are the main components of nerve gases, herbicides, pesticides and insecticides and are also used to create plastics and solvents.
“They are widely used in agriculture in the crops we eat,” Perry said. “We use them in structural applications in homes and buildings, apartment buildings, as well as in ornamental lawn maintenance. They are available for consumer purchase, so exposures to organophosphates have been shown to be relatively widespread.”
N-methyl carbamates are structurally and operationally similar to organophosphates, killing insects by damaging their brains and nervous systems. They are used to make insecticides that are applied to a “variety of agricultural, fruit, and vegetable crops for control of beetles, borers, nematodes, weevils, and similar pests,” according to the U.S. Centers for Disease Control and Prevention.
“As we start to close the net around factors that could negatively impact fertility, these pesticides start to rise to the top,” said Dr. Alexander Pastuszak, assistant professor of surgery and urology at the University of Utah School of Medicine in City of Lago Salgado. He was not involved in the new study.
“There is enough evidence to really start to say that yes, these types of compounds can negatively affect fertility in men,” he said. “Ultimately, you don’t know the impact on actual fertility until and unless you start trying to get pregnant.”
A significant impact
The study, published Wednesday in the journal Environmental Health Perspectives, examined studies around the world on the two chemicals and found 20 that met study inclusion standards. These studies looked at 42 different levels of impact among 1,774 men in 21 different study populations.
Men who were more exposed to pesticides, such as those who work in agriculture, had significantly lower sperm concentrations than men who had less exposure to organophosphates and N-methyl carbamates, the study found.
Sperm concentration is a measurement of sperm per ml of semen, while sperm count is the number of millions of sperm in the entire ejaculate. Sperm count, along with the total number of sperm progressively swimming in semen, are the most important measures of future fertility, according to experts.
However, sperm concentration “is an important measure of sperm quality for comparing men across studies because it adjusts for variability in semen volume,” Perry said.
Animal studies have clarified how these pesticides can affect sperm, the study found. They appear to directly interfere with sex hormones, damage cells in the testicles and alter neurotransmitters in the brain that affect sperm production, the study said.
“Sperm is an incredibly sensitive endpoint when it comes to men’s overall health,” Perry said. “My best advice is to be aware of insecticides in the environment and recognize that avoiding unnecessary exposure to insecticides is a good thing, especially if you are planning to start a family and want to conceive children.”
A “public health problem”
It’s not just pesticides. Researchers are exploring the role of obesity, poor diet, chronic disease and exposure to environmental toxins such as pollution, PFAS and other potential toxins. Some are even considering radiation from cell phone use as a potential reason for the precipitous drop in sperm count.
A recent study found that men ages 18 to 22 who said they used their phone more than 20 times a day had a 21% higher risk of having an overall low sperm count. Men also had a 30% higher risk of low sperm concentration. The study did not specify whether the men called, texted or used their phones to do both.
Pesticide exposure in food is still a significant problem: An advocacy group recently gave major food manufacturers a collective F for failing to reduce pesticide levels in the foods they sell as promised.
“This is truly a public health issue,” Perry said. “We can take an individual approach, but it is on a population basis that people are exposed to pesticides and other factors.
“Measures are needed to reduce exposure to insecticides so that if men want to have children, they can do so without worrying about global reductions in sperm concentration,” she added.
What to do about sperm count
However, when it comes to pesticide exposure in food, there are actions consumers can take. Choosing organic foods is a surefire way to reduce pesticide exposure, experts say.
Although organic foods are not more nutritious, most have little or no pesticide residue, according to Alexis Temkin, a toxicologist at the Environmental Working Group, a nonprofit research and advocacy organization that focuses on consumer health, toxic chemicals and pollutants.
“If a person switches to an organic diet, pesticide levels in urine decrease rapidly,” she told CNN in a previous interview. “We see it time and time again.”
If organic produce is unavailable or too expensive, “I would definitely recommend peeling and washing well with water,” Temkin said. “Stay away from detergents or other advertised items. Rinsing with water will reduce pesticide levels.”
The Environmental Working Group creates an annual list of the most and least pesticide-laden non-organic products that consumers can use to shop. In their 2023 Buyer’s Guide to Pesticides in Produce, researchers found 210 different pesticides in the 12 foods.
Additional tips on washing produce, provided by the U.S. Food and Drug Administration, include:
- Wash your hands with warm water and soap for 20 seconds before and after preparing fresh produce;
- Rinse the produce before peeling it, so that dirt and bacteria are not transferred from the knife to the fruit or vegetable;
- Using a clean vegetable brush to scrub firm produce like apples and melons;
- Dry the product with a clean cloth or paper towel to further reduce bacteria that may be present.
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Source: CNN Brasil
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