By Catherine Donaldson-Evans
AOL Health, March 25, 2010
Men who consume a quart of cola — fewer than three 12-ounce cans or two 20-ounce bottles — or more a day have sperm counts that are about 30 percent lower than those of men who don’t, according to a Danish report published March 25 in the American Journal of Epidemiology.
Researchers noted that caffeine is probably not the culprit because similar results were not found in men who drink coffee and tea regularly.
“It’s important to note that the men who drank a lot of cola were also different in many other ways,” lead researcher Tina Kold Jensen, M.D., of Rigshospitalet in Copenhagen, Denmark, told Reuters Health.
Though the sperm levels of the cola-drinking men studied were still within normal ranges by World Health Organization standards, those with fewer sperm are generally more likely to be infertile.
But a preeminent male fertility expert in the United States shot down the study’s merit.
“This study is absurd,” Sherman J. Silber, M.D., director of the Infertility Center of St. Louis and the author of “How to Get Pregnant,” told AOL Health. “You have to average at least 12 sperm counts over at least a six-month period … because there is so much variation in sperm count within the same man.”
The Danish researchers said they wanted to see how the increase in caffeinated soda consumption among Denmark’s youth was affecting their reproductive health.
Among the 2,500 young men studied, those who didn’t drink cola had higher sperm counts: an average of 50 million per milliliter of semen. The 93 men who drank more than a liter, or 34 ounces, of cola per day averaged about 35 million sperm per milliliter.
“No one would think that 35 million and 50 million, especially with something as variable as sperm count, is a meaningful difference,” Dr. Silber said.
He also said that the relatively small number of men who drank cola every day and had lower sperm counts is suspicious.
The non-cola drinkers also lived healthier lifestyles — eating less fast food and more fruits and vegetables — than the cola drinkers, the study found.
Though the researchers said other sources of caffeine didn’t have significant effects on the quality and amount of sperm, they couldn’t conclusively say whether the findings were the result of the cola consumption or the unhealthy diet, or whether both were having an impact on their sperm.
Dr. Silber said that since the sperm levels of most men fluctuate, it isn’t out of the ordinary for counts to be 35 million on some occasions and 50 million on others — and so he believes the findings mean nothing.
“The study is sensationalistic,” he told AOL Health. “It is frankly stupid and very misleading.”