FAT AND CHOLESTEROL
As excess cholesterol in the bloodstream flows through the body’s arteries, some of it binds permanently to the walls of the coronary and other arteries. More bits of cholesterol, plus fat and debris from the bloodstream, may join the buildup on the wall, eventually creating a lump inside the artery. This cholesterol/fat lump may continue to grow until the artery is completely blocked, triggering a heart attack. (Imagine a small car stuck on the side of the freeway. Traffic flows smoothly until another car smacks into the first, then another and another, creating a pileup. Now traffic is slow, but cars are still able to get through. Unfortunately, more and more cars join the pileup until the freeway is completely blocked and no cars can get through. Something similar can happen in the arteries, with cholesterol, fat, and debris taking the place of the cars.)
In other cases, a small blood clot which has formed in another part of the body may drift into the partially blocked artery and get stuck at the lump, blocking the blood flow. This occurs more often in the brain than the heart. (That would be like a
large truck getting stuck in a small tunnel, preventing any other cars from getting through.) Heart attacks can also be caused by stress-related arterial spasms. Muscles surrounding the coronary arteries may suddenly go into spasm and clamp down, stopping the blood flow. If an artery has already been narrowed by cholesterol/fat plugs, a minor spasm can be a major disaster.
Like cholesterol, fat participates in the making of the lumps that can clog arteries and block the flow of blood. And it has another way of causing trouble for the heart. If you have someone eat a very high-fat meal, draw a sample of their blood, set the blood in a test tube, and sit down to watch, you’ll eventually see the fat from the blood rise to the top of the tube, as the fat did in milk bottles in the days before milk was homogenized. It will be obvious; it’s the sludgy stuff. That same sludge clogs up your bloodstream, turning fluid that flows easily through the pipes, and some of the things in that fluid, into, well, sludge. For example, the red blood cells that carry oxygen are normally able to move easily through these blood vessels. But as the fat from the food gets into the bloodstream, the blood cells slush together, looking like a stack of coins. This is called the rouleau effect. Up to nine hours later, the blood cells may still be stuck together in misshapen clumps in the tiny blood vessels. How well can the red blood cells carry out their jobs when they’re bent out of shape and stuck together? Not very well. That’s why 4 or 5 hours after a fatty meal, when the blood fat levels have risen quite a bit, certain people have chest pains, abnormal EKGs, and possibly heart attacks. The fat also prevents the release of a substance called nitrous oxide, which relaxes and dilates the arteries.
I sometimes draw blood from my patients, then show them how milky and sludgy their blood looks (instead of fluid). I also have them look at a drop of their blood through a special dark-field microscope. They can see how their blood is filled with “snow,” which are white patches of fat. Later, after they’ve adopted a low-fat diet, they can see how clear and fluid their blood looks. It’s a great motivator.
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