Background: The negative effects of obesity and health benefits of maintaining an ideal body weight have been described since the time of the ancient Greeks. Obesity is defined by abnormal fat accumulation with body mass index (BMI) ≥30 kg/m2 and is reaching epidemic proportions worldwide. This widespread issue is leading to reduced quality of life and early death. Obesity contributes to metabolic syndrome (a combination of abdominal obesity, diabetes mellitus, hypertension, elevated triglycerides/cholesterol), cardiovascular disease, and testosterone deficiency.
The problems: Testosterone, Fertility, Sexual Health
The decrease in testosterone is proportional to obesity degree, and works by shutting down the “central fuel” for testosterone production. This is in part due to increased estrogen levels resulting from an increase in the enzyme (aromatase) which is found in fat cells. With increased fat cells, there is increased activity of an enzyme called aromatase. Low testosterone in turn also contributes to excess fat accumulation and decreased muscle mass. Obesity promotes a state of chronic inflammation, damaging vessels and further decreasing testosterone through inflammatory markers (such as IL-6) and sleep apnea (sleep disorder with abnormal breathing pauses). There is interaction of many complex factors from obesity which promote obesity, diabetes, and lower testosterone which further worsens these conditions.
In terms of fertility, obesity leads to excess estrogens which may have a negative effect on sperm production. Decreased physical activity and increased upper abdominal and upper thigh fat can lead to hotter testicular temperature which can further harm sperm production. Environmental toxins (such as organochlorines which are found in insecticides) can accumulate in fat cells and have been to shown to correlate with decreased sperm production. Increased inflammation can lead to an increase in agents (called reactive oxygen species-ROS) that damage sperm and decrease sperm counts.
In addition to low sex drive (resulting from low testosterone), erectile dysfunction occurs more commonly than in normal weight individuals due to disturbance of vasculature and decreased testosterone.
Treatment: Diet and weight loss are the first and most important step to improve testosterone and erectile dysfunction. If this is ineffective, testosterone replacement (with one of a variety of medications) may be considered including both benefits and possible risks with your physician. Certain treatments may not be suitable especially for men over 65 years of age or those with cardiac issues, but more studies are needed to assess the best population for treatment. Multiple clinical trials show that testosterone replacement therapy (with either topical or injectable testosterone, clomiphene citrate, or anastrazole- discussed in other posts) can reverse changes of obesity by increasing lean body mass, decreasing fat mass and waist size, blood sugar, and cholesterol. Obese men with increased estradiol (<10:1 ratio of testosterone to estradiol) are candidates for aromatase inhibitors (i.e anastrazole) which prevent conversion of testosterone to estradiol. An additional option is surgical management (bariatric surgery, gastroplasty) to achieve weight loss which is also shown to be beneficial in improving hormonal profiles of obese men. For infertile obese men without sperm in the ejaculate (azoospermia), microTESE (microdissection testicular sperm extraction) has resulted in similar sperm retrieval rates but decreased pregnancy rates with increased obesity.
–Matthew Wosnitzer, M.D.
July 19, 2013