Eating a diet high in junk food could make sperm sparse, slow and obese, a pair of studies presented Monday at the American Society for Reproductive Medicine annual meeting in Orlando, Fla. suggest. The research highlights an apparent link between nutrition and semen quality, which dovetails nicely with the whole survival-of-the-fittest idea.
Diets rich in red meat and processed grains seem to impair the ability of sperm to move about, while diets high in trans fats appear to lower the amount of sperm found in semen, USA Today reported October 19.
"The main overall finding of our work is that a healthy diet seems to be beneficial for semen quality," said Audrey J. Gaskins, lead author of the first study. Currently a doctoral candidate in Harvard School of Public Health's department of nutrition, Gaskins' colleagues included researchers from the University of Rochester and the University of Murcia in Spain.
"Specifically, a healthy diet composed of a higher intake of fish, fresh fruit, whole grains, legumes and vegetables seems to improve sperm motility," Gaskins explained, "which means a higher number of sperm actually move around, rather than sit still."
The study's conclusions are based on work with 188 men between the ages of 18 and 22 recruited in Rochester. Food questionnaires were completed, with diets being categorized as either "Western" (including red meat, refined carbs, sweets and energy drinks) or "prudent" (composed of fish, fruit, vegetables, legumes and whole grains).
Semen tests were then conducted to assess sperm movement, concentration and shape.
Although diet seemed to have no impact on either sperm shape or number, motility was impacted, with "Western" diets linked to reduced movement, even after accounting for factors such as race, smoking history and body-mass index
The second study, led by Dr. Jorge Chavarro, an assistant professor of nutrition and epidemiology at the Harvard School of Public Health, revealed that men who eat diets that contain a relatively high amount of trans fat had lower sperm concentration levels. They even found higher amounts of trans fat in their sperm and semen--meaning chubby sperm?
The conclusion was drawn from work with nearly 100 men attending a fertility clinic, all of whom underwent nutritional and semen quality analysis.
Even after adjusting for a wide array of factors such as age, drinking and smoking histories, BMI, caffeine intake and total calories consumed, the authors found that the more trans fatty acids consumed, the lower an individual's sperm concentration, although they didn't see an effect on sperm mobility.
Neither study has been peer reviewed, so the results must be considered preliminary until they are published in a journal. However, Dr. Edward Kim of the University of Tennessee's graduate school of medicine in Knoxville told USA Today: "I think that this research is certainly very suggestive that dietary factors may have an impact on male infertility." (Kim is also president of the Society for Male Reproduction and Urology.)
The studies raise the age-old male philosophical question: Babes or burgers? Each man will have to decide for himself.