Cholesterol may endanger your heart

LDLs are the most common fat-and-protein particles in your body. Like their parents, the VLDLs and their cousins the IDLs, LDLs are soft enough to squeeze between the cells of your blood vessel walls, dragging cholesterol into your coronary arteries (the blood vessels leading away from your heart).

Once inside an artery, cholesterol particles may get caught on the infinite number of chinks in the artery wall. Stuck in place, the cholesterol now snags other particles floating by, eventually creating deposits called plaque. In time, the plaque on the artery wall may grow thick enough to block the flow of blood through the blood vessel, or a piece of plaque may break off, triggering the formation of a blood clot that can also block the artery. Either way, the sequence is called a heart attack.

As a general rule, heart docs assume that the more cholesterol you have floating through your bloodstream — especially the “bad” LDL cholesterol — the higher your risk for plaque build-up in your arteries and the higher your risk of a heart attack. In other words, to lower your risk of heart attack, you must lower your cholesterol, particularly those “bad” LDLs.

But this simple equation may not be the solution for every human body. In December 2007, the results from a clinical trial of the new drug ezetimibe (Zetia) showed that taking the medicine, either alone or in combination with the statin drug simvastatin (Zocor), definitely lowered “bad” cholesterol, but also hastened the buildup of arterial plaque for some of the people in the trial.

In other words, simply lowering their LDLs did not protect these people from a heart attack. Something else, such as an individual tendency to pile up arterial plaque, also seemed to be at work. (Conversely, people with high cholesterol but clear arteries may have the opposite attribute — an inherent ability to resist plaque — that explains the puzzle of why some people with high cholesterol do not have heart attacks.)

Cholesterol's bad news

Cholesterol can clog your brain

This is a very short section because everything you need to know about how cholesterol may be hazardous to your brain can be summed up in one word — ditto.

That’s ditto to what you've just read about cholesterol and your coronary arteries. Having high levels of cholesterol may also increase the risk of plaque in a cranial artery. Plaque can block the flow of blood travelling through a cranial artery to your brain, triggering a stroke.

Prevention is another ditto. The preventative steps that you can take in relation to your coronary arteries and your heart can also benefit your cranial arteries and your brain.

Cholesterol can build boulders in your gallbladder

Cholesterol is a building block for the bile you need to digest fats. This side of cholesterol behaves like the good Dr. Jekyll. But every yin has its yang, and the bad Mr. Hyde is gallstones.

A gallstone is a rock-like lump that forms when the normal percentages of fat in bile change so that the fat (in this case cholesterol) clumps in a lump in your gallbladder or in the duct leading from the gallbladder to your intestines.

Approximately 80 to 95 percent of all gallstones are made primarily of cholesterol. (The rest are made primarily of calcium.) According to the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), as many as 42 million Americans have gallstones. Many of the risk factors for cholesterol gallstones are the same as those for heart disease, such as the following:

·         Diabetes

·         High-cholesterol diet

·         Obesity

·         Smoking

But here’s an odd fact: Yes, being overweight raises your risk of gallstones, but so does going on a diet and losing weight very rapidly. When your body is deprived of its normal quota of calories and fat, your liver is likely to increase its natural production of cholesterol. Sometimes you can’t win for losing, which includes the symptoms, signs, and consequences of gallstones: pains, nausea, belching, vomiting, fever, chills, and, maybe, surgery to remove your gallbladder.

If your doctor recommends yanking out the offending organ, do not to worry. Or at least, not too much. True, all surgery has potential risks, but modern gallbladder surgery is performed laparoscopically (translation: through very small incisions that heal quickly). Once the gallbladder is out, you probably won’t notice much change in your ability to eat what you want. Your gallbladder is just a storage bin where bile produced by the liver is parked until your body yells, “Yo! Send down some bile.” After surgery, your liver still produces bile, which still makes its way into the intestine to help you digest fats.

While some people do develop gastric rumbles, okay, diarrhea, after eating a large, very fatty meal, most patients do just fine so long as they stick with food/meals containing moderate amounts of fat. What’s moderate varies from person to person. If you exceed your own personal limit, trust me, you will know.

Blood

Blood circulates through a system of vessels called arteries and veins. Arteries carry blood away from the heart; veins carry blood back to the heart. The average human body has about 5 quarts of blood. Large people may have slightly more; small people may have slightly less. Every 60 seconds, about 1⁄5 quart of blood flows out of your heart through your coronary arteries. Sixty seconds after that, the blood zips through your entire circulatory system and heads back to your heart.

The life span of one red blood cell is about 120 days for a man and about 14 days less for a woman. Men have more red blood cells — about 4.5 to 6.2 million per cubic microliter of blood compared to 4 to 5.5 million for women. Because males have more red blood cells, they also have higher values of hemoglobin, the pigment in red blood cells that carries oxygen throughout the body. They also have higher levels of iron, an important element in hemoglobin.

White blood cells play a primary role in your immune system as avengers that zero in on invaders, such as bacteria, to chew them up and spit them out. The normal number of white blood cells is exactly the same for men and women — 4,100 to 10,900 per microliter of blood. Blood is a vehicle for nutrients, medications, and other circulating particles such as — what a surprise — the lipoproteins that carry cholesterol.

By the way, the blood for a cholesterol test always comes from a vein, not an artery. Blood from a vein is easier and safer to obtain, and it’s a representative sample of what’s in your body. And yes, clenching your fist does make your vein pop up so it’s easier to puncture.

MPO

Measuring MPO

White blood cells are the body’s natural defense against inflammation and infection. When the white blood cells sense trouble, they release myeloperoxidase (MPO), a protein that can knock the heck out of the bugs causing the inflammation and infection.

But MPO may also irritate arteries and short-circuit natural body chemicals that keep “bad” cholesterol particles from glomming on to artery walls, thus contributing to the buildup of plaque inside your blood vessels. In July 2007, the Journal of the American College of Cardiology published data from a study of more than 1,000 healthy Brits showing that, over the years, those with the highest blood levels of MPO had the highest risk of coronary artery disease (CAD).

In other words, high blood levels of MPO may signal artery trouble ahead, even when other indicators, such as LDL levels, are fine. Naturally, the researchers want to see more studies before they stick an MPO test onto your yearly lab tests, but, as one of the researchers said, “MPO looks like a ‘keeper’ that will one day become part of clinical care.”

Many insurance companies, including Medicare, may not pay for CRP or MPO blood tests because they argue that if you have elevated levels, you need to make all the necessary lifestyle changes (lose weight, treat high blood pressure, stop smoking, eat a healthy diet, and so on). You should be doing this anyway! However, sometimes demonstrating to people that their risk of a heart attack in the next five years is great can stimulate them to become more serious about making lifestyle changes.