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Just a couple of years ago, one of the few things scientists were pretty sure did not trigger cardiac problems was infection. They're not quite so sure anymore. Strong evidence now suggests that the immune system plays a major role in heart disease. The initial damage is done by things like high blood pressure, smoking, oxidized LDL and triglycerides, which weaken and damage the inner walls of veins and arteries. Then the immune system responds, just as it's designed to do. Instead of fixing these problems, though, the immune response makes them worse. For one thing, the body tries to repair physical tears in blood vessels as it would any other wound: blood platelets rush to the site, clump together and form a clot, a biological bandage that binds up the injury. A clot on the outside of the body--a scab, in other words--eventually falls off with no problem. But inside a vein or artery, especially one that has been narrowed with plaque deposits, a clot can get snagged, causing a heart attack.
Plaque buildup too may be an unintended by-product of immune-system action. When oxidized fatty molecules damage vessel walls, the tissues become inflamed--engorged with immune cells whose job it is to fight the invaders. Instead of vacuuming up the oxidized molecules, however, the immune cells become entangled with them; the whole mess welds itself onto the tough, sticky plaques that narrow veins and arteries. That, researchers believe, is one reason aspirin is so good at preventing second heart attacks: not only does it thin the blood and keep things flowing, it also damps down inflammation.
This same sort of blood-vessel inflammation, doctors believe, may be triggered by bacterial and viral infections. Chlamydia (which generally starts as a venereal disease) and gingivitis (an infection of the gums) have both been implicated in heart disease, and more recently so has the herpesvirus that causes cold sores. In the case of herpes, especially, it's far too early to tell whether this link is real or will evaporate under closer scrutiny.
It's known as the French paradox: people who live in France eat huge quantities of saturated fat (in the form of butter, cheese and other milk products), yet they have one of the lowest rates of cardiovascular disease in the world. One compelling explanation is that the French also drink wine, usually in moderation. Too much alcohol can destroy just about every organ in the body, the heart included. But investigators have discovered through clinical trials that people who take an occasional nip have about a 20% lower risk of heart disease than do teetotalers.
The mechanism isn't entirely clear, but alcohol may boost blood levels of HDL, the good cholesterol that cleans plaque off arterial walls. Two to four drinks a week seem optimal for men, one to three for women. Since excess alcohol consumption is the second leading cause of preventable death in the U.S., says Dr. Charles Hennekens of Harvard Medical School, "I'm opposed to a wide public health recommendation to drink alcohol. But I'm ready to consider it for a particular patient after going over his or her risks and benefits."