Although no longer a controversial issue, obesity is increasingly linked with fertility problems of men, always in relation to semen quality. And, in fact, has been added to the list of risk factors for male infertility, next to snuff, alcohol, drug use, exposure to toxic agents, some diseases or treatment with certain drugs.
However, all that has been shown so far is that overweight (defined by a body mass index (BMI) greater than 25) and waist circumference are directly related to lower semen volume and sperm concentration less . But they have not obtained conclusive evidence of how it affects motility and morphology thereof.
The truth is that the sperm of obese men have a lower presence of testosterone and other hormones than those who are not overweight, which can be related to a decreased testicular function (hypogonadism) which adversely affect the parameters that determine male fertility : concentration, motility, morphology and DNA fragmentation.
A study conducted at Stanford University in which the semen of 468 men of couples who wanted to have a child was analyzed has revealed that BMI and waist circumference adversely affect ejaculate volume and in the number of sperm per milliliter of semen
However, these data alone do not say much, because they are considered normal seminal volume of between 1.5 and 5 milliliters. Furthermore, this study did not detect a relationship between BMI and waist circumference with a higher or lower sperm count, reduced sperm vitality or an increase of malformed sperm.
In fact, some of the men included in the study had had at least one child previously. In conclusion, therefore, only I could ensure that obesity may influence the degree of male fertility, but does not establish a cause-effect relationship between excess weight and infertility.