Obesity has long been linked to erectile dysfunction — the inability to perform sexually. Now it seems that extra pounds lower sexual desire itself.
A study of 2,435 Italian males found that obesity correlated with reduced testosterone levels. The greater the obesity, the lower the testosterone levels. In general, low testosterone means a drop in libido, or sexual desire.
A recent presentation at the Heart Failure Congress in Lisbon, Portugal, linked heart failure to androgen deficiency in the aging male (ADAM), also known as late-onset hypogonadism or "male menopause." The presentation also linked heart failure to endocrine changes that contribute to a drop in libido.
To make matters worse, a drop in libido often coincides with erectile dysfunction, or ED, which is widely regarded as an indicator of "silent" heart disease.
That should add to the overweight male's sense of urgency about dropping a few pounds.
Eighty percent of men with ED are overweight or obese. This correlation could have psychological causes — depression, for example, which also correlates with obesity, or anxiety about looking sexually unattractive.
A more likely cause, however, is heart disease, which impairs the delivery of blood to every part of the body, including the penis. Heart disease also damages the endothelium — the thin lining of blood vessels — which produces the nitric oxide needed to sustain an erection. (Viagra works by inhibiting the enzyme that breaks down nitric oxide, which allows the molecule to linger in the blood stream, enabling an erection to last longer.)
Obesity, according to the Italian study, appears to lower testosterone, in part, at least, because fat cells convert testosterone into the female hormone estradiol. This loss of testosterone combined with an increase in a female hormone contributes to the loss of sexual interest. Testosterone therapy often restores erectile function, but so does weight loss. In another study, also conducted in Italy, 32 percent of obese men who lost a modest 5 percent of their body weight — usually less than 20 pounds — reported improvement in sexual function .
Also, a recent study conducted in Australia involving 31 obese men with Type 2 diabetes concluded that losing 5 to 10 percent of their body weight improved sexual desire as well as erectile function.
If a man feels a decline in sexual interest, why not just supplement his flagging testosterone levels with one of the products now available for "low T?" Many men are doing just that. A new study finds that prescriptions for the heavily advertised androgen gels and patches have more than tripled since 2001 in men over 40, and 25 percent of the men did not even bother to have a blood test to confirm low testosterone.
And when Australian physician Gary Wittert, of the University of Adelaide, lead author of the Australian study mentioned above, recently solicited males at risk of developing diabetes for a study that included free testosterone injections, he got 800 responses in one day.
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But there are other ways to slow testosterone decline with age, in Wittert's opinion.
"Men who had declines in testosterone were more likely to be those who became obese, had stopped smoking or were depressed at either clinic visit," Wittert said in a statement announcing his study's results. "It is critical that doctors understand that declining testosterone levels are not a natural part of aging and that they are most likely due to health-related behaviors or health status itself."
One bright spot he observed in his data: "Regular sexual activity tends to increase testosterone."
Tom Valeo writes about health matters. He can be reached at firstname.lastname@example.org.