Men with obesity can improve their semen quality if they lose weight and maintain the weight loss, a new study shows.
Men all over the world are suffering from deteriorating semen quality—often referred to as an outright fertility crisis. The new study offers good news for some men experiencing problems.
“It was surprising to us that such a big improvement can be shown in the semen quality in connection with a weight loss. And as 18% of Danes have obesity, this new knowledge may actually make a difference,” says Signe Torekov, professor in the biomedical sciences department at the University of Copenhagen who headed the study together with Romain Barres, professor at the Novo Nordisk Foundation Center for Basic Metabolic Research.
The new findings may be good news for fertility, as a link between higher sperm count and getting pregnant faster has previously been shown.
The study, published in Human Reproduction, included 56 men with obesity, aged 18-65 years, with a body mass index between 32 and 43.
Weight loss improves sperm quality
It has long been known that obesity is associated with reduced semen quality, Torekov says. Previous studies have also suggested a link between weight loss and increased semen quality, but these studies have had so few participants or such modest weight loss that it has been difficult to draw conclusions from them, she explains.
“But now we are ready to do just that. This is the first long-term randomized study, where we have shown that semen quality in men with obesity improve with a sustained weight loss,” Torekov says.
“The men lost an average of 16.5 kg (about 36 pounds) which increased the sperm concentration by 50% and the sperm count by 40% eight weeks since the weight loss. During the 52 weeks, the trial lasted following the weight loss, the men maintained the improved semen quality. But only the men who maintained the weight loss: after a year, these men had twice as many sperm cells as before their weight loss. The men who regained weight, lost the improvements in semen quality,” she explains.
The study is a sub study of a major publication on weight loss, published in the New England Journal of Medicine in May 2021. A total of 215 Danes with obesity participated in the larger study. It was among these participants that 56 of the men also provided semen samples to investigate whether semen quality and weight loss could be related.
In the trial, all participants first followed an eight-week regimen with a low-calorie diet, resulting in a weight loss. Then the participants were randomly divided into four groups.
Two of the groups received placebo medication, while the other two groups received obesity medication. Among the two placebo groups, one group had to follow an exercise program where each week, they had to do a minimum of 150 minutes of moderate physical training or 75 minutes of hard training—or a combination.
The other group did not change their usual level of physical activity. The two groups that received obesity medication were divided in the same way, into a group with and a group without an exercise program.
After a year, the group that only exercised and did not receive medication, as well as the group that only received obesity medication and did not exercise, maintained the weight loss. The group that received both obesity medication and exercised lost additional weight and improved their health.
The placebo group—those who thought they were given medication, but did not exercise—had regained half of the weight loss with aggravation of many of the risk factors related to development of type 2 diabetes and cardiovascular disease.
Source: University of Copenhagen