July 10, 2008

Losing Weight May Improve Sperm

Obese men should consider losing weight before having children, because fatter men have less seminal fluid and more abnormal sperm, a Scottish researcher says.

Dr. A Ghiyath Shayeb of the University of Aberdeen and colleagues looked at the results of seminal fluid analysis in 5,316 men who attended the Aberdeen Fertility Centre with their partners for difficulties in conceiving.

The researchers said 2,037 of these men had complete data on their body mass index. The scientists divided the men into four groups according to their BMI, from being underweight to being considerably overweight.

Taking into account other characteristics that could affect the analysis, such as smoking, alcohol intake, age, social deprivation and the length of time of abstinence from sex prior to producing a semen sample for analysis, the researchers found men with the optimal BMI of 20 to 25 had higher levels of normal sperm than the others. They also had higher semen volume.

However, there was no significant difference between the four BMI groups in sperm concentration or ability to move. The researchers did not look at DNA damage in the sperm.

The findings were presented at the 24th annual conference of the European Society of Human Reproduction and Embryology in Barcelona, Spain.