High levels of blood fats (lipids), especially cholesterol, are known to play a role in erectile dysfunction(ED).
Dyslipidemia is a condition marked by abnormal concentrations of lipids or lipoproteins in the blood. Hyperlipidemia, meaning high lipid levels (or fat) in the blood, is a very common disorder in the United States. Hyperlipidemia includes several conditions, but it usually means that you have high cholesterol and high triglyceride levels. Hypercholesterolemia is the presence of excess cholesterol in the blood.
Cholesterol and other fats can't dissolve in the blood. They are transported to and from the cells by special carriers called lipoproteins. The lipoproteins contain cholesterol, protein and fat. The three major lipoprotein particles are high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL).
The blood test for a total cholesterol level measures blood cholesterol in all lipoproteins combined. Men with a total cholesterol greater than 240 mg/dl have a 2.7-fold increased risk for having moderate to severe erectile dysfunction. This makes an elevated serum cholesterol one of the most important risk factors for the subsequent development of erectile dysfunction.
Good and Bad Cholesterol
Cholesterol is typically known as "good" and "bad" cholesterol. HDL, or high density lipoprotein, is the so-called "good" or "healthy" cholesterol which is responsible for the return of lipoproteins from peripheral tissue to the liver for excretion in a process known as reverse cholesterol transport. We want elevated levels of HDL in our blood streams.
LDL, or low density lipoprotein, results from the processing of very low density lipoprotein (VLDL) remnants. LDL is also known as the "bad" cholesterol; it plays a major role in the development of atherosclerosis or plaque in our arteries. We want low levels of LDL in our blood streams.
While this is a very simplified discussion of cholesterol, what's important is the concept of total cholesterol and both the "good" and "bad" cholesterols, or HDL and LDL.
Blood Fats Including Cholesterol and their Effect on Erectile Dysfunction
Our discussion centers on the effects of lipid disorders on erectile dysfunction. It's been well documented that high lipids or high total cholesterol are commonly associated with erectile dysfunction. In many men with erectile dysfunction, hypercholesterolemia is the only risk factor seen.
It is a mistake to isolate risk factors for erectile dysfunction, such as diabetes or dyslipidemia and treat them individually rather than treating the core problem to address all the complications. For example, let's look at lipid management. Lipid disorders almost always coexist with the syndrome known as the metabolic syndrome and with Type II diabetes. About 25% of US adults have the metabolic syndrome.
This syndrome includes "central" obesity (in men, a waist circumference greater than 40 inches, in women, a waist circumference greater than 34 inches), an elevation of the triglycerides (in most people, the result of increased carbohydrate intake), decreased HDL cholesterol (less than 40 mg/dL in men and less than 50 mg/dL in women), blood pressure greater than 135/85 mmHg or existing anti-hypertensive treatment and elevated fasting blood glucose (fasting blood glucose greater than 110) . This constellation of risk factors has also been called by other names including syndrome X and insulin resistance syndrome.
In a person with metabolic syndrome, tobacco's effects can be synergistic with more deleterious effects from tobacco than for the smoker who does not have metabolic syndrome.
The published guidelines for lipid disorder management are well-known by primary care physicians and specialists. The recently updated guidelines emphasize therapeutic life style modifications focusing on exercise, diet, weight loss and, of course, smoking cessation as the cornerstones of care. If these aggressive life style modifications are not successful, then drug management should be introduced. The primary target is decrease of the LDL, the "bad" cholesterol with a goal of LDL less than 100 mg/dL.
Recommendations for initiation of drug treatment are variable but generally when patients have other risk factors, it's desirable to have a lower LDL. There are many common and effective treatment options for lipid disorders.
Statins and their Effect on Erectile Dysfunction
The gold standard for treatment of lipid disorders is a class of drugs called statins. Statins are among the best selling drugs in US history in part because of an extensive direct to consumer marketing campaign. It's even been suggested that, as this decade progresses, every man and woman in America will benefit from treatment with statins. The statins are widely used and are very effective. Statins inhibit an enzyme in the liver, called HMG-CoA reductase, which inhibits the manufacturing of cholesterol in the liver and decreases the LDL. A statin may be used alone or in combination with a fibrate or with nicotinic acid, which is in the B vitamin family. Statins have some side effects but are generally very safe and very well tolerated.
What is very important about the statins is that several studies have shown that treatment with statins, particularly atorvastatin (Lipitor®), can improve sexual dysfunction and the response to oral PDE-5 inhibitors (Viagra®, Levitra® and Cialis®) in men who did not respond to the PDE-5 inhibitors alone. The pilot study supported the concept that statins can help improve endothelial dysfunction, the primary defect seen with erectile dysfunction.
Other Medications for High Cholesterol
Another type of medication used in the treatment of hyperlipidemia is cholesterol absorption inhibitors which interfere with the absorption of cholesterol. The only drug currently marketed is ezetimibe (Zetia®).
One of the better drugs, niacin or nicotinic acid, is also one of the oldest drugs. It inhibits HDL (the "good" cholesterol) clearance and reduces the liver production of the bad cholesterol also known as VLDL. Niacin is relatively well tolerated but may cause some flushing and should be used in caution in patients with diabetes.
Bile acid sequestrants are an older type of lipid lowering drugs which bind fats in the diet and prevent their absorption, thus decreasing cholesterol by decreasing absorption. Other drugs include fibrates which affect fatty acid metabolism and triglyceride clearances and are involved with peroxisome proliferator-activated receptor (PPAR), a family of transcription factors that are involved with glycemic control. We will hear a lot more about PPARs in the future.
Perhaps one of the best treatments is also one of the oldest and most natural treatments. Omega-3 fatty acids, typically derived from coldwater fish and other sources, are becoming more and more popular. They have a multitude of positive effects in the human body and are currently indicated for people with high triglyceride levels. There is a wonderful body of work by Dr. Nicholas Perricone, a dermatologist who promotes omega-3 fatty acids.
In summary, lipid metabolism is an extremely important component of the overall picture of function and maintenance of erections. Erectile dysfunction can be one of the earliest symptoms seen and can help facilitate the diagnosis of a lipid disorder. As with all medications, you should consult your primary care clinician before embarking on a lipid lowering regimen.
The most important point is that erectile dysfunction is a symptom of subsequent cardiovascular disease. We cannot stop the progression of erectile dysfunction without therapeutic life style modification. The drugs that are currently available for the treatment of erectile dysfunction merely treat the symptom and do nothing to change the underlying causes. This is the wrong approach to treating erectile dysfunction. It is extremely important to know your lipid profile, to discuss it with your clinician and to manage it either with a therapeutic life style modification or medication or a combination of both.
References: See Bibliography
Posted August 2008
Updated August 2009