(CNN) – If sperm were an animal, science could worry that it is heading towards extinction in Western nations.
The total sperm count in North America, Europe, Australia and New Zealand fell by up to 60% in the 38 years between 1973 and 2011, according to research, an acceleration of a trend that began in the 1940s. More studies Recent show that the trend continues.
At the same time, studies show a simultaneous decrease in testosterone levels: the hormone needed to develop a man’s muscle and bone mass and increase his sexual desire.
Why? No one knows for sure. The role of radiation, air pollution and chemicals in our food, clothing and water is debated. Smoking, alcohol consumption and obesity probably play an important role.
This could reduce the nutritional quality of the typical western diet, according to a new study published Friday JAMA Urology.
“This study is the largest to date to examine the pattern of diet with testicular function in men,” said study author Feiby Nassan, a researcher at the T.H. Harvard Chan.
The study found that, on average, men who generally ate a westernized diet of pizza, snacks, sweets and processed foods produced about 68 million fewer sperm when ejaculating than men who ate a healthier and more balanced diet.
A man is considered to have a low sperm count if he has less than 39 million sperm per ejaculation or less than 15 million sperm per milliliter. A low sperm count can negatively affect a man’s ability to get his partner pregnant, and it can be a key marker for man’s overall health.
“Fertility is not only important for babies,” Nassan said, adding that new research recently shows that fertility is related to the overall health and life expectancy of a man.
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A big difference
The study looked at 2,935 normal-weight Danish men, with an average age of 19, who underwent a physical exam to determine their fitness for military service (something that all men in Denmark have to do after they turn 18 ).
Blood and semen samples were taken, and the men completed a questionnaire asking how often they had eaten 136 foods in the last three months.
The study analyzed four food patterns:
- The “prudent” and healthy pattern, which mainly consumed fish, chicken, vegetables, fruits and water.
- The “open sandwich pattern”, a typically Danish diet with a higher intake of processed cold meats, whole-grain breads, mayonnaise, cold fish, condiments and dairy products.
- The vegetarian pattern, with a high intake of vegetables, soy milk and eggs, with little or no red meat or chicken.
- And the “unhealthy” western pattern, with more pizza, snacks, chips, candy, sugary drinks, red and processed meats, and highly processed grains.
The men who closely followed the prudent eating pattern, characterized by a large amount of fish, chicken, vegetables, fruits and water, were associated with the highest sperm count. This was followed by the semivegetarian and then the “smørrebrød”, or Danish feeding style.
“The average sperm count of men who had the highest adherence to the ‘prudent’ pattern was 68 million higher than men who had the highest adherence to the ‘western’ pattern,” said Nassan, with 95% confidence intervals of 43 and 93.
In addition, the average sperm count of men who had the highest adherence to the vegetarian pattern was almost 33 million higher than men who mostly consumed the least nutritious western diet.
CNN wrote about the preliminary results of the study last year. At that time, Charles Lindemann, professor emeritus and researcher at the University of Oakland in Michigan, who was not involved in the research, said the study’s findings “could be an important clue if it resists scrutiny.”
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A diet rich in processed foods, he said, “may be responsible for the known trend that has been recorded in the recent past of sperm counts in progressive decline.”
Nassan said his findings show that eating shellfish, poultry, nuts, whole grains, fruits and vegetables gives the body antioxidants and omega-3 fatty acids “essential for good sperm production.”
“Changing the diet pattern can be a simple and economical change” to protect a man’s testicular function, Nassan said.
“I think it’s not just‘ you are what you eat ’but also‘ your sperm is what you eat. ”
Susan Scutti contributed to this report.
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