Persons most commonly affected: Most men experience this at some point in their lives, usually by age 40.

Organ or part of body involved: Male sexual organ.

Symptoms and indications: Inability to attain or maintain erection of the penis for sexual intercourse.

Causes and risk factors: Causes are either by physical or psychological problems. It may be brought on by job-related stress, fear of causing pregnancy, unresolved conflicts about sexuality, or fear of sex after a heart attack or major surgery. Drug and alcohol abuse are also among the leading cause of erectile dysfunction. Physical factors include an imbalance in the hormonal system that causes a decrease in production of testosterone (the male hormone necessary for an erection), the use of certain drugs for the treatment of hypertension, particularly diuretics and beta blockers, diseases of the nervous system, such as multiple sclerosis, structural abnormalities of the penis, injury to the penis, and malfunctioning of the circulatory system, which can interfere with the blood flow to the penis, and diabetes. Diet is another common cause. Just as a high-fat, low-fiber routine can inhibit blood flow to the heart, it can also block the arteries that lead to the penis.

Prevention: Limit or avoid the use of alcohol and other similar drugs. Exercise regularly. Reduce stress, get enough sleep, and deal with anxiety or depression. Avoid cigarette smoking and maintain normal blood pressure and cholesterol levels because smoking and high cholesterol can affect blood vessels. Men with diabetes should strive to keep blood sugar levels under control. Because certain medications have been associated with erectile dysfunction, ask your doctor about possible side effects before you start using any new prescription. Eat a healthful diet that is high in biber and nutrients. Good sources of fiber include fresh raw vegetables, apples, oats, and whole grains. Vitamin E dilates blood vessels and improves blood flow. Foods that are high in this nutrient include wheat germ, soy products, leafy green vegetables, and whole grain cereals. Enjoy soybeans, pumpkin seeds, and sunflowe seeds as snacks or in salads. They are excellent sources of zinc, which aids the prostate and improves testosterone levels. Eliminate junk and processed foods from your diet. Do not eat large meals just before sex. Your body will be too focused on digestion to concentrate on desire. Moderate your intake of caffeine and alcohol.