The HDL/triglycerides trap - high density lipoprotein - interview with William Castelli, director of the Framingham Heart Study - interview

Nutrition Action Healthletter, Sept, 1990 by Bonnie Liebman

The HDL/Triglycerides Trap

If your cholesterol is below 200, most doctors--and the government--say you needn't worry about getting a heart attack. Wrong, says William Castelli, director of the Framingham Heart Study. If you have a low HDL ("good") cholesterol level, you may still be at risk.

"There's a subgroup of people who have an HDL under 40 and triglycerides over 150," he explains. "These people have galloping proression of their cholesterol deposits, which will eventually lead to heart disease, and the average physician is not picking it up."

It's also wrong for physicians to assume that women and older people needn't worry about their colestrol, says Castille. He corrects these and other common miscomceptions in an interview staring on page 5.

Q: The National Cholesterol Education Programs says that your risk of heart disease isn't high if your cholesterol is less than 200. Is that wrong?

A: It could be. Twenty percent of heart attacks occur in people with cholesterols under 200. You'll miss them if you only measure total cholestrol. you can't interpret a total cholesterol between 150 and 200 unless you also measure HDL.

Q: How high should your HDL ["good"] cholesterol be"

A: Your total cholesterol divided by your HDL should be under 4.5. The ideal ratio is u nder 3.5. At ratio between 3.5 and 4.5, your altherosclerosis is slowly progressing. If you live long enough, you'll make lesions in your arteries.

Q: Why is HDL so important?

A: Your cells need cholesterol to make cell membranes and hormones. But when your total cholesterol is over 150--or your LDL ["bad"] cholesterol is over 90--the cells have more cholesterol than they can use and no way to get rid of the excess. They can't break down or oxidize it, so it starts to pile up as a waxy deposit that will eventually choke the cells.

The only way to get rid of the excess cholesterol is to get HDL to pick it up and bring it to the liver, where 95 percent of it goes out of the body. As John Oram, of the University of Washington is Seattle, says: without enough HDL you could turn into a candle.

Q: Isn't a high LDL the best predictor of heart disease risk?

A:LDL is a much better predictor than total cholesterol. But with a total between 200 and 240, the total/HDL ratio predicts your risk of heart disease 3-4 times better than LDL and 5-6 times better than total cholesterol.

If your total is over 240, LDL is a better predictor, because few people have enough HDL to bail them out of a higher LDL.

Howver, you will find the rare person who has a total cholesterol of 300 and a high HDL, say 100. Instead of starting him on a diet, the doctor puts him on the drug lovastatin. But this guy will go to his doctor's funeral, and needed only a diet.

Q: Aren't people with the highest cholesterols at greatest risk?

A: When I went to Framingham in 1965, it was taught that you only treat people with cholesterol over 300. Unfortunately, if you only treat those people, you miss 75 percent of the heart attacks. The cholesterol of the average man who gets a heart attack is 225. Most heart attacks occur between 200 and 240.

Now, Elizabeth Whelan [of the industry-funded American Council on Science and Health] says the National Cholesterol Education Program calls a cholesterol between 200 and 240 "borderline" as if they're not sure if it's bad. Then she asks whether we should bother people for something we're not sure about.

You know, Whelan claims she's an epidemiologist, but the first rule of epidemiology is that you've got to go where the epidemic is. If you go to Peoria and the epidemic is in Hackensack, you'll miss the epidemic, elizabeth. Well, the epidemic is between 200 and 240.

Q:Should people worry about their triglycerides?

A: There's a big debate about triglycerides. In women, it's a better predictor of heart disease risk than LDL, unless their total cholesterol is over 350 and their LDL is sky-high.

In both men and women, we think there's a subgroup with high triglycerides--150 or higher--who also have very low HLD--under 40. [Triglycerides are transported in the blood primarily in very low density lipoproteins--VLDLs.]

These people apparently have a different kind of VLDL, which turns into a kind of LDL that is even worse for their arteries than ordinary LDL. We need to find these people.

Q: Arent doctors told to worry about triglycerides only if they're over 250?

A: Yes. That's part of the problem. We want doctors to consider triglycerides high if they're over 150, because the bulk of the people who have this bad VLDL have triglycerides between 190 and 210, to go along with HDLs under 40.

Q: Are those the only clues to finding these people?

A: No. We think that this syndrome starts in men and women in their middle age when they put on a spare tire and get an increased waist-to-hip ratio.

They also have the highest blood sugar you can have without having diabetes--between 95 and 110--so the average physician will miss it. That's because they have insulin resistance. It's as if their insulin doesn't work as well, so blood sugar backs up in their blood. And they go on to develop deabetes at twice the rate of other men and women.