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Can obesity cause erectile dysfunction?

BACKGROUND

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Not that long ago, erectile dysfunction (ED) was a taboo subject. It was the topic of crude jokes and was not discussed in polite company. However, since the introduction of Viagra and other similar drugs, the topic of ED has gone mainstream. Commercials appear on almost every televised sporting event, and men’s magazines are filled with ads to “increase your sexual performance”. Celebrities such as NASCAR star Mark Martin, NFL coach Mike Ditka, and even former Republican presidential candidate Bob Dole have provided endorsements for various products. Although many people complain that the television ads are too explicit and are not suitable for family viewing, statistics show that men are now seeking treatment more willingly. Erectile dysfunction drugs have become more than a billion-dollar industry, and for millions of men these drugs have become a godsend.

However, despite the increased awareness of ED, there is still a basic lack of understanding about what causes the disorder and what can be done to prevent it. Many men assume that there is only one treatment option: pills. They are looking for a quick fix rather than a long-term solution. The three dominant drugs -Viagra, Cialis, and Levitra – all work by blocking an enzyme which allows blood to leave the penis, thereby increasing inflow and allowing erections to last longer. Although these drugs are generally very effective, they often have side effects and may stop working after a few years. And of course, pills will not provide complete restoration.
As with most health problems, prevention is best. One of the most preventable causes of ED is obesity. According to the Massachusetts Male Aging Study (http://www.ncbi.nlm.nih.gov/pubmed/8254833 ), 4 out of 5 people who report symptoms of ED are overweight or obese. A body mass index (BMI) in excess of 25 is considered overweight and a BMI in excess of 30 is considered obese. A BMI in excess of 40 is considered extremely obese. (To calculate your own BMI, obtain your height and weight, then use this online calculator: http://www.nhlbi.nih.gov/guidelines/obesity/BMI/bmicalc.htm.) A 2003 Harvard study by Bacon et al (http://www.ncbi.nlm.nih.gov/pubmed/12899583 ) noted that men who have a body mass index greater than 28.7 (about 195 pounds for a 5’9″ male) have a 30 percent greater risk of erectile dysfunction than those men with a normal BMI.

WHY DOES OBESITY CAUSE ERECTILE DYSFUNCTION?

In spite of the support that obesity is linked to erectile dysfunction, it is still not well understood how extra belly fat leads to decreased sexual performance. While it was initially thought that most cases of ED among obese men had only psychological roots, now it is believed that numerous physical mechanisms are involved as well.

The most important way that obesity influences a man’s sex life is by decreasing the amount of blood that flows to the penis. An erection occurs when the blood vessels leading to the penis dilate, causing it to fill with blood. The penis must store blood in order to keep an erection. Therefore, the ability of a man to develop and maintain penile erection depends on the health of his vascular system. It is well-accepted that the fatty foods and lack of exercise that cause weight gain can lead to atherosclerosis – the build-up of a waxy plaque on the interior of blood vessels.

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When atherosclerosis occurs in the penile artery, the blood flow decreases or gets blocked, diminishing erectile function. Because the arteries in the penis are so small – 1mm to 2mm in diameter – they are affected a lot sooner than those in the heart, which are 3mm to 4mm in diameter. Therefore, ED can often be a warning sign of impending cardiovascular disease.

Another element affecting the health of the vascular system is the endothelium – the thin layer of cells that line the interior surface of all blood vessels. The erection process begins when the endothelium releases nitric oxide, a molecule that signals the surrounding muscles to relax in order for the blood vessels to dilate. (Viagra and similar drugs work by increasing the amount of nitric oxide in the endothelium.) However, when the endothelium is damaged, the endothelium may not release enough nitric oxide to produce or sustain an erection. Obesity, especially excess belly fat, has a damaging effect on vascular endothelium.

* Obesity can also affect erectile dysfunction by lowering testosterone levels. Testosterone is the primary sex hormone in men, and it plays an important role in both libido and sexual function. In a very recent study published in 2013 in _European Journal of Endocrinology _( http://www.ncbi.nlm.nih.gov/pubmed/23425925), low testosterone levels (also known as hypgonadism) were found in 75% of men considered very obese (BMI > 40). The link between obesity and low testosterone levels was found in men at all ages, even in young men and teenagers. The researchers also concluded that the common decrease in testosterone seen in older men is not due to age, but rather to increasing body weight. Another recent study published in 2013 in _Fertility and Sterility_ (http://www.ncbi.nlm.nih.gov/pubmed/23507475) showed that the testosterone decreases in men as they grow older can be reversed with weight loss.

In addition to these biological factors, there are also social and psychological factors associated with obesity. Obese people often have feelings of shame about their bodies and a lower sense of self esteem than their thinner peers. In a society that puts a premium on beauty and thinness, obese people may experience discrimination based on weight, including reduced chances of landing good jobs and decreased likelihood of dating or finding a marriage partner. Teasing and bullying can occur, especially during adolescence. This combination of negative body image and social prejudice could certainly affect the ability of overweight people to have satisfactory sexual relations.

CAN WEIGHT LOSS TURN THINGS AROUND?

Establishing a link between obesity and erectile dysfunction is one thing, but finding a way to improve erectile function is another. However, two recent studies have found that weight loss can indeed improve sexual function for overweight men with ED.

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In a follow-up to the Massachusetts Male Aging Study published in _American Journal of Epidemiology_ in 1999 (http://www.ncbi.nlm.nih.gov/pubmed/10731462), Feldman et al found that men who were overweight at baseline were at an increased risk of developing erectile dysfunction. In contrast, men who initiated physical activity in midlife had a 70% reduced risk for erectile dysfunction relative to those who remained sedentary. In quantitative terms, this means that sedentary men may be able to reduce their risk of erectile dysfunction by performing regular physical activity at a level of at least 200 kcal/d, which corresponds to walking briskly for 2 miles.

In a landmark Italian study published in the _Journal of the American Medical Association_ in 2004 (http://jama.jamanetwork.com/article.aspx?articleid=198993), Esposito et al examined the effects of lifestyle changes on erectile dysfunction. This study took a group of 110 men between 35 and 55, who all had some degree of ED. All of the men were obese but otherwise healthy, and were randomly assigned to two equal groups. The first group was given detailed and individualized advice about reducing their total body weight through healthy food choices and by increasing physical activity. The second group just continued their usual care. By the end of the study, the BMI of men in the first group decreased more than the BMI of those in the second. In addition, in the first group there was a 22 percent improvement in erectile dysfunction, and 31 percent of the same men reported being at a level that no longer categorized them as having erectile dysfunction. In contrast, only 6 percent of the men in the second group were no longer considered to have erectile dysfunction. The improvement in erectile dysfunction was associated with improvement of both endothelial function and markers of systemic vascular inflammation.

The findings of this study led Dr. Christopher S. Saigal, a urologist at UCLA, to write an editorial in the same issue of the journal encouraging doctors to consider weight loss and exercise as the initial treatment for obese patients with ED. Saigal comments: “At a time in which obesity has become a public health crisis, this study provides evidence of efficacy for what perhaps should be the first-line treatment for obese patients with ED. This treatment strategy produces many benefits for the patient if it is successful and incurs no untoward risk if it is not.” As the Esposito study shows, even losing as little as 5%-10% of your body weight can lead to major improvements in your health, including blood pressure, cholesterol levels, and insulin sensitivity. And of course, losing weight can also provide an ego boost that carries over into the bedroom. According to Stephen Josephson, Ph.D., a psychologist at New York-Presbyterian Hospital, “People need to feel good about themselves [to] overcome performance anxiety and other things in the sex arena, and sometimes it’s as simple as getting into shape.”

THE BOTTOM LINE

If you are significantly overweight and you want to reduce your risk of ED, you need to make a healthy body weight a top health priority. Weight loss, increased physical activity and proper diet are factors that can protect from ED. Losing as little as 5 to 10 percent of body weight offers meaningful health benefits to people who are obese, even if they never achieve their “ideal” weight, and even if they only begin to lose weight later in life. (National Heart, Lung, and Blood Institute. _Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults_ . 2002)

According to the recently released obesity guidelines for the Obesity Society, American Heart Association, and American College of Cardiology (http://circ.ahajournals.org/content/early/2013/11/11/01.cir.0000437739.71477.ee), there is no ideal diet for everyone. Doctors need to work with their obese patients to figure out the best plan for them, whether it’s vegetarian, low sodium, a commercial weight loss program, or low-carb. The most effective weight loss programs include 2-3 in-person meetings a month for at least 6 months, and most people should consume at least 500 fewer calories a day to lose weight.

If you are already suffering from ED, a complete physical examination by your doctor or healthcare provider is essential. In some cases, erectile dysfunction may be a sign of an underlying medical condition. Your doctor can determine if any other conditions are involved and help you choose the best and safest therapy. Take your medications as prescribed and follow your doctor’s advice on diet and exercise.

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