Semen production of overweight and obese men might be of a poorer quality than that of normal weight men in terms of its fertility potential, according to clinical studies published in "Epidemiology" and "Fertility and Sterility." In men with a high body mass index, weight loss might help improve semen production and thereby increase fertility, but extreme weight loss is unlikely to increase semen quality. Research published in "Human Reproduction Update" found that underweight men also had lower-quality semen production compared with that of men with normal body weights.
Obesity and Semen Production
Studies published in "Epidemiology" and "Fertility and Sterility" concluded that obesity negatively affects semen production in terms of both sperm count and overall fertility potential. According to a case-cohort study of 2,157 men published in "Fertility and Sterility" in 2010, body mass index, or BMI, was negatively correlated with sperm count in patients 20 to 30 years old. Accordingly, researchers concluded that obesity might reduce fertility in men. Similarly, a 2006 "Epidemiology" study found that overweight and obese male subjects were more likely to have fertility problems. Dr. Ana Carolina Martini, a researcher at National University of Cordoba in Argentina who also has studied the relationship between BMI and fertility, says that weight loss might improve an overweight or obese man's sperm quality and thereby increase his fertility.
Low BMI and Semen Production
While losing extra pounds to achieve a healthy weight might improve semen production and fertility, losing too much weight might negatively impact semen production. A meta-analysis published in "Human Reproduction Update" in 2009 examined the impact of BMI on several semen characteristics related to fertility. Two studies included in the meta-analysis found that underweight subjects had poorer sperm quality than men of normal weight, in terms of their sperm count, concentration and motility.
Significance
Quality of semen production is important for couples who are trying to get pregnant, and obesity might cause semen quality to decrease. Meanwhile, obesity levels in many parts of the world are "dramatically on the rise," as characterized by the World Health Organization. According to Martini, while obesity will not necessarily render a man infertile, it might affect his sperm quality in such a way that reduces his fertility. Therefore, according to Martini, as the incidence of obesity grows, it is expected that the number of obese men with reduced fertility will rise as well.
Considerations
While being underweight or overweight might negatively impact semen production in terms of fertility potential, weight is not the only factor determining a man's fertility. Another factor that might affect a man's semen production in a way that reduces his fertility is his age. A 2007 metastudy published in "Journal of Andrology" states that, compared with younger men, older men have reduced semen volume per ejaculate, which is an important variable related to fertility. Many medical conditions also might reduce a man's fertility. These include cancer, exposure to toxins and infections, according to MayoClinic.com. Certain lifestyle factors, including nutrition, stress, drug use and alcohol use, also might affect a man's sperm quality, says MayoClinic.com.
References
- "Epidemiology"; Reduced Fertility Among Overweight and Obese Men; Sallmén et al.; September 2006
- "Fertility and Sterility"; Obesity and Age Affect Male Fertility Potential; Paasch, et. al.; December 2010
- "Human Reproduction Update"; The Impact of Body Mass on Semen Parameters and Reproductive Hormones in Human Males: A Systematic Review with Meta-Analysis; November 2009
- World Health Organization: Obesity and Overweight
- "Journal of Andrology"; Ejaculate Volume Is Seriously Underestimated When Semen Is Pipetted or Decanted Into Cylinders From the Collection Vessel; Cooper, et al.; January 2007
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