By Lisa Rapaport

(Reuters Health) – Young men who care about their sperm quality might want to lay off the cheeseburgers and fries, according to a new study that links a typical Western diet with a lower sperm count.

Men in the study who ate a mostly Western diet characterized by pizza, fries, sweets, sodas and red and processed meats typically had a lower sperm count – by about 26 million – than men who ate far less of these unhealthy foods. With a Western diet, men also had lower levels of reproductive hormones needed for optimal fertility.

Conversely, men with the healthiest eating habits – with lots of fish, chicken, vegetables, fruits, and water – typically had a sperm count 43 million higher than those who ate the lowest amounts of these foods.

“Your sperm is what you eat,” said coauthor Dr. Feiby Nassan of the Harvard T. H. Chan School of Public Health in Boston.

Diets rich in seafood, poultry, nuts, whole grains, fruits and vegetables provide antioxidants and omega-3 fatty acids that are essential for good sperm production, Nassan said by email.

“Our results suggest the possibility of using dietary intervention as a possible approach to improve sperm quality of men in reproductive age,” Nassan said.

A normal sperm count can range from 15 million to 200 million sperm per milliliter of semen.

Sperm quality and certain sex hormone levels have decreased substantially over the past few decades, driven in part by worsening diets in many parts of the world, the researchers note in JAMA Network Open.

The current analysis included 2,935 healthy men in Denmark, ages 19 or 20 on average. Researchers divided them according to how closely their diets matched four patterns: a Western diet; a healthy diet described as a “prudent pattern” of eating; a so-called “open-sandwich” diet consisting of whole grains and lots of cold cuts, fish, condiments, and dairy; and a vegetarian-like diet with lots of veggies, soy, milk, and eggs and little if any red meat or chicken.

Total sperm count with the Western diet was significantly lower than with any of the other three eating patterns.

The study wasn’t designed to prove whether diet directly affects sperm or fertility. Researchers also focused on young, healthy men who might not yet be trying to conceive, and they didn’t examine what happened in older men who wanted to become fathers.

Still, the study adds to evidence suggesting a healthy diet is good for men’s reproductive health, Dr. Muhammad Imran Omar of the University of Aberdeen in the UK said by email.

And, men, like women, should try to adopt a healthy diet, cut back on alcohol and stop smoking months before they want to start trying for a baby.

“However, men should be aware that it takes three months to produce sperm,” said Allan Pacey, a researcher at the University of Sheffield in the UK who wasn’t involved in the study.

“If a man alters his diet on a Friday it won’t improve his sperm by Monday,” Pacey said by email.

SOURCE: JAMA Network Open, online February 21, 2020.