Heavy Men Have Fewer Sperm

Heavy men should consider going on a diet if they want their partners to bear them children, said Dr. A Ghiyath Shayeb, of the University of Aberdeen at the 24th annual conference of the European Society of Human Reproduction and Embryology. Shayeb said his research indicated that men with a high body mass index (BMI) had less seminal fluid and a greater number of abnormal sperm.

Contributing Factor

Along with his colleagues, Dr. Shayeb analyzed the sperm of 5316 men undergoing fertility treatment in conjunction with their female partners at the Aberdeen Fertility Centre. Shayeb's team discovered that 2037 male participants already had data on their BMI's and this led to the idea that male obesity might be a contributing factor in fertility problems. Researchers have long known that female obesity leads to fertility problems, and the team thought male obesity as a factor in infertility looked like a promising avenue for research.

The scientists split the men into four groups based on their BMI's, from those who were underweight, to those who were very obese. The researchers made the effort to rule out other factors that might skew the results, such as alcohol consumption, age, cigarette smoke, lengthy abstinence from sex, and societal factors as they looked for the link between BMI and semen quality. The men in Group B had the best BMI of all the participants, 20-25, as defined by the World Health Organization (WHO), and were found to have the highest number of healthy sperm than those in the other groups. The volume of semen was also found to be highest in this group. Meantime, none of the groups bore any statistical differences in terms of motile sperm or sperm concentration.

DNA Damage

The researchers decided not to analyze the sperm samples for DNA damage, and limited the study to the normal semen analyses performed for the purpose of IUI, since all of the male participants had had such an analysis performed at least one time during their treatment at the center. Other studies have already suggested a link between male obesity and DNA damage in sperm. "Our findings were quite independent of any other factors," said Shayeb, "and seem to suggest that men who are trying for a baby with their partners, should first try to achieve an ideal body weight. This is in addition to the benefit of a healthy BMI for their general well being."

Shayeb comments that healthy lifestyle changes can lead to a normal BMI and healthier sperm.


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