Your friend Lou has just had a heart attack. He was lining up a shot off the 17th tee—something he does every Saturday morning—when he dropped his driver, stumbled to the golf cart and slumped over the seat. The pain was overwhelming. But Lou’s golf partners got him to the hospital in minutes. And after doctors opened a clogged artery, Lou is doing fine.
Yet the whole experience has left Lou—and you—somewhat shaken. Lou is only 45 years old. He gets lots of exercise, balances work with play and keeps an eye on his cholesterol. He is nobody’s fool.
So why did he have a heart attack?
For at least a decade, doctors have known that the most important ways to prevent a heart attack are to avoid tobacco smoke, eat a low-cholesterol diet, keep dietary fat to a minimum, sweat through at least three workouts a week and reduce stress across the board.
But today doctors are also beginning to realize that specific nutrients—particularly vitamin C, vitamin E and beta-carotene—may be just as important.
Nobody knows whether a lack of these nutrients can actually lead to heart disease, but it’s certainly starting to look that way. In the ongoing Nurses’ Health Study, being conducted at Harvard Medical School and Brigham and Women’s Hospital in Boston, researchers compared the diets of more than 73,000 nurses and found that a diet rich in vitamin E reduced heart attack risk by 52 percent, a diet rich in vitamin C reduced risk by 43 percent, and a diet rich in beta-carotene, one of the nutrients that give orange and yellow vegetables their color, reduced risk by 38 percent. What’s more, nurses who got a rich supply of all three nutrients were 63 percent less likely to have heart attacks than those who did not.
How do these nutrients work?
“Nobody really knows,” says Howard N. Hodis, M.D., director of the atherosclerosis research unit at the University of Southern California School of Medicine in Los Angeles. At this point, scientists have more theories than answers. But it looks as though these three nutrients might work by actually neutralizing LDL cholesterol, the “bad” kind that damages your arteries, before it can do any harm.
| Food Factors What you eat--and what you don't eat--in large part determines whether you eventually develop heart disease. Here are a few tips to help you keep the number one killer in this country at bay. Cut the fat. "We need to follow the American Heart Association's Step I guidelines," says Howard N. Hodis, M.D., director of the atherosclerosis research unit at the University of Southern California School of Medicine in Los Angeles. "In general, that means a total cholesterol intake of less than 300 milligrams a day and a total fat intake of less than 30 percent of total calories a day." Most Americans get approximately 40 percent of their calories from fat. You can lower the amount of fat in your diet by cutting back on fatty meats and whole-fat dairy products, avoiding fast foods, candies and most baked goods and eating more fruits and vegetables. Get hooked on fish. In a study of several thousand men who smoke, researchers in the Honolulu Heart Program at the University of Hawaii at Manoa found that those who ate fish more than twice a week cut their risk of death from heart disease in half. "One of the magic bullets against heart disease could be fish," says William Castelli, M.D., former director of the Framingham Heart Study and now medical director of the Framingham Cardiovascular Institute in Massachusetts. "The societies whose diets emphasize fish have the lowest heart attack rates." Eat your fruits and veggies. A Dutch study of more than 800 men between the ages of 65 and 84 found that the more bioflavonoids these guys consumed (they got them from tea, onions and apples), the less likely they were to die from heart disease. Bioflavonoids, chemical compounds related to vitamin C that may neutralize "bad" LDL cholesterol and reduce the tendency of red blood cells to stick together and block arteries, are found in nearly all plants, so fruits and vegetables are likely to be good sources. Dine on soy. Soy products such as tofu contain isoflavones, which are naturally occurring substances that may prevent the formation of plaque on artery walls. Don't forget the garlic. Several studies indicate that one-half to one clove of garlic, eaten daily, can significantly lower total cholesterol. High cholesterol is a major risk factor for heart disease. |
Understanding the Disease
To comprehend just how powerfully these nutrients protect your arteries, you need to take a look at what causes heart disease to begin with.
Most heart disease, including angina and electrical problems that are responsible for sudden cardiac death, is actually caused by atherosclerosis, a condition in which cholesterol and cells roaming your bloodstream build up along the walls of coronary arteries and cause them to narrow. Narrowing reduces the flow of blood to the heart and increases the chance that a bunch of blood cells might clump together and get wedged in the artery. When that happens, or if an artery suddenly spasms, blood flow to the heart is cut off, triggering a heart attack.
Sometimes referred to as hardening of the arteries, atherosclerosis is a silent process that can begin in childhood. It starts when the cells lining an artery are damaged by constant pounding from high blood pressure, by repeated exposure to toxic chemicals such as those in cigarette smoke, by repeated exposure to high concentrations of LDL cholesterol or even by a bacterial or viral infection.
Once the damage occurs, the body tries to repair it. LDL cholesterol and blood cells called monocytes are attracted to the site, where they try to patch the damage. When that fails, cells from other areas of the arterial wall move in and form a protective mat, usually referred to as plaque, over the injury. The plaque hardens as it takes up calcium, and it continues to grow until it protrudes into the artery’s hollow interior. Eventually, the plaque can narrow the artery’s interior enough to slow the flow of blood to your heart and set you up for a heart attack.
Enter the Three Musketeers
Doctors have tried for years to prevent the development of atherosclerosis by telling people to stop doing those things that damage arteries to begin with: “Stop smoking!” “Stop eating high-cholesterol foods!” “Stop eating high-fat foods!” But over the next few years, doctors may actually be able to go one step further: They may be able to tell people how to interrupt the formation of atherosclerotic plaque, no matter what its cause.
It’s a complicated story that scientists are only beginning to untangle. But it seems that LDL cholesterol may not be able to contribute to the formation of atherosclerotic plaque unless the fat in the LDL particle goes rancid when exposed to oxygen in the arterial wall, a process called oxidation, says Balz Frei, Ph.D., associate professor of medicine and biochemistry at Boston University School of Medicine.
Fortunately, laboratory studies indicate that there are at least two nutrients that can prevent the LDL particle from becoming oxidized, which is why the nutrients are called antioxidants, explains Dr. Frei.
The nutrients? Vitamin C and vitamin E, the same nutrients that scientists have found reduce the risk of heart disease when present in your diet. Beta-carotene also was originally thought to protect LDL against oxidation, but studies have shown that this is not the case, says Dr. Frei. “Scientists are now exploring other mechanisms that would explain beta-carotene’s beneficial effects against heart disease—perhaps the rejuvenation of vitamin E,” he adds.
Vitamin E: Neutralizing Cholesterol
Although all three nutrients seem to have roles in thwarting atherosclerosis, vitamin E may be the most protective.
In a study at the University of Texas Southwestern Medical Center at Dallas, 24 men were given either placebos (blank pills) or supplements combining 800 international units of vitamin E, 1,000 milligrams of vitamin C and 30 milligrams (about 50,000 international units) of beta-carotene. After three months, scientists found that it took twice as long for particles to oxidize in the men taking supplements compared with the men taking placebos. The supplement group also had a 40 percent reduction in the number of LDL particles oxidized compared with the placebo group. These results indicate that the antioxidant regimen used in the study might slow, and perhaps even prevent, atherosclerosis.
Curious as to which nutrient might be doing most of the antioxidant work, researchers went back to the drawing board and compared the group taking the antioxidant “cocktail” with a similar group of men taking 800 international units of vitamin E alone.
The result?
No significant differences.
It’s not that vitamin C and beta-carotene weren’t doing their jobs, concluded the researchers. But it is possible that their efforts were simply overshadowed by the sheer power of vitamin E.
Scientific studies indicate that vitamin E hops on board the LDL particle when it forms in your liver and then enters your bloodstream. Once part of the LDL particle, vitamin E helps prevent the particle from going rancid and forming artery-clogging plaque, explains Dr. Frei. Instead, the LDL particle and its vitamin E passenger actually pass into the artery wall, where they set up housekeeping. And as long as there’s a plentiful supply of vitamin E and other antioxidants to keep replacing the vitamin E that’s used up, the LDL particle should remain harmless.
At least that’s the theory. Fortunately, vitamin E seems to work just as well at preventing heart disease in real life as it does at preventing plaque in the laboratory.
In the Health Professionals Follow-Up Study of almost 40,000 men, conducted by researchers at Harvard School of Public Health, men who took at least 100 international units of vitamin E a day for at least two years reduced their risk of heart disease by 37 percent. A companion study of more than 87,000 nurses between the ages of 34 and 59 found similar results.
Vitamin E even seems to benefit those who are already suffering from advanced heart disease.
In a study at a hospital in Albuquerque, New Mexico, of 440 people who had undergone angioplasty, a procedure to open blocked arteries, the 57 people who took an average of 574 international units of vitamin E a day had about half of the incidence of reblocked arteries of those who did not.
The same seems to hold true for people who’ve had bypass surgery. When scientists at the University of Southern California asked 162 men ages 40 to 59 who had undergone heart bypass surgery which vitamins they took, they found that the men who reported taking more than 100 international units of vitamin E daily had significantly slower buildup of plaque clogging their arteries.
What does this mean to us? “Well, we can answer that only partly,” replies Dr. Frei. “Several studies have suggested that an increase in vitamin E to a level of about 100 international units or more per day is protective against heart disease. That level cannot be achieved by dietary means, so you have to supplement. But I think it’s too early to make a specific recommendation, although I’ll tell you that after publication of the results of the Nurses’ Health Study and the Health Professionals Follow-Up Study, a lot of doctors started to take vitamin E.
“It’s sort of a paradoxical situation, where the evidence appears to be good enough for many doctors to take vitamin E but not good enough for them to recommend it to their patients,” Dr. Frei adds.
Although some doctors involved in vitamin E research do not recommend vitamin E supplements, others feel that 100 to 200 international units of vitamin E a day might prove beneficial. While the Daily Value is only 30 international units, this amount is certainly considered safe, says Dr. Frei. If you have heart disease, you should discuss vitamin supplements with your doctor.
Beta-Carotene: Preventing Heart Attacks
Although sometimes overshadowed in the lab by vitamin E, beta-carotene, the nutrient that gives carrots their color, is a champion on the dinner plate when it comes to fighting heart disease.
One study after another touts the heart-healthy benefits of beta-carotene, beginning with the Physicians’ Health Study at Harvard Medical School. In this study, a group of 333 men between the ages of 40 and 84 who had severe heart disease were given 50 milligrams (83,000 international units) of beta-carotene every other day. Beta-carotene had no effect on the men’s conditions during the first year. But from the second year on, the men’s risk of heart attack was literally cut in half.
What’s more, other investigators have found that the protective effects of beta-carotene may be even more pronounced among those who have risk factors that predispose them to heart disease, such as smoking and high cholesterol.
In a study at the Johns Hopkins University School of Medicine in Baltimore, for example, researchers compared blood levels of beta-carotene and other carotenoids of 123 people between the ages of 35 and 65 who had had a first heart attack with those of people of similar age who had not had a first heart attack.
“The study found that smokers with the lowest blood levels of beta-carotene had about 31¼2 times the risk of heart attack of people who had high levels of beta-carotene and did not smoke,” says Debra A. Street, Ph.D., who led the research at Johns Hopkins and is now an epidemiologist with the Food and Drug Administration.
People with high cholesterol levels may also find that beta-carotene and its carotenoid cousins protect their hearts. In a 13-year study at the University of North Carolina at Chapel Hill and the University of Tennessee in Memphis, researchers monitored more than 1,800 men between the ages of 40 and 59 who had high cholesterol levels. When comparing the 282 men who subsequently had heart attacks with those who stayed healthy, the researchers found that those who had high levels of beta-carotene and other carotenoids in their blood at the start of the study were 40 percent less likely to have heart attacks than those with lower levels.
It’s not that you can go out and smoke cigarettes or load up on high-cholesterol foods, says Dexter Morris, M.D., Ph.D., assistant professor at the University of North Carolina at Chapel Hill School of Medicine, who led the study. But “the higher your carotenoid levels, the lower your risk of getting a heart attack,” he says.
Gelcap or Carrot?
Researchers across the board resoundingly recommend eating five or more servings of fruits and vegetables a day, including some servings rich in carotenoids, to protect yourself against heart disease. They are less likely to recommend beta-carotene supplements.
Why would beta-carotene in the diet be better than beta-carotene in a gelcap? “One possibility is that in some of these studies, it’s not just the beta-carotene that’s good for you, it’s also something else,” says Dr. Morris. Beta-carotene represents only one-fifth of the most common carotenoids found in orange and yellow fruits and vegetables. So it’s entirely possible that whether you get your beta-carotene from a carrot or from a gelcap full of carrot oil, these other carotenoids may contribute to some of the effect that’s being credited to beta-carotene.
“A second possibility is that there may be a kind of therapeutic window for beta-carotene,” Dr. Morris continues. “In other words, some is good, but too much may cause problems. There’s one theory, for example, that at higher levels, beta-carotene may interfere with the protective effects of something else.” Just what that might be is pure speculation, he says.
Most of these reservations are not just the normal cautions that folks have come to expect from careful scientists. They are instead based on a mammoth study of 29,000 male Finnish smokers that was designed to tell whether beta-carotene and other synthetic supplements can prevent lung cancer and heart disease.
The problem is that most researchers expected to find that the supplements either reduced the chances of cancer and heart disease in the Finns or didn’t do anything at all. Instead, the researchers found that male smokers who took 20 milligrams (about 33,000 international units) of synthetic beta-carotene a day actually increased their risk of both.
Some researchers have attributed this finding to the fact that heavy smokers are frequently heavy drinkers, and heavy drinking destroys beta-carotene in the body. Other researchers feel that taking a high dose of beta-carotene may inhibit the absorption or effect of other antioxidants.
Still others haven’t a clue.
“Although most experts believe that the Finnish findings are unique, that doesn’t warrant ignoring the data,” says Dr. Hodis. “We have to wait until more data come in. And until it does, I think that people should stop smoking and eat a well-balanced diet that includes the Daily Values of all vitamins and minerals.”
Vitamin C: The Antioxidant Attack Ship
Although the roles played by vitamin E and beta-carotene are becoming fairly well defined, vitamin C’s role in preventing atherosclerosis is still emerging.
Some real-life studies indicate that after a decade of looking good in the laboratory, vitamin C may not do as much as scientists had hoped. But other studies indicate that it clearly contributes to preventing heart disease.
When researchers at the University of California, Los Angeles, checked the amounts of vitamin C taken by more than 11,000 men and women between the ages of 25 and 74, for example, they found that people who got more than 50 milligrams of vitamin C a day, in addition to a multivitamin/ mineral supplement, reduced their risk of death from cardiovascular disease by 28 percent.
These findings seem to indicate that vitamin C is just as important as vi tamin E and beta-carotene in preventing atherosclerosis, which makes sense when you look at what each of the nutrients does and how they complement one another’s work.
To understand the value of these nutrients, “you have to distinguish between the two different classes of antioxidants,” explains Dr. Frei. “One class is a group of water-soluble antioxidants that includes vitamin C. The other class is a group of fat-soluble antioxidants that includes vitamin E.
“The mechanisms by which they work are similar, but they work in different compartments of the body,” says Dr. Frei. “The water-soluble antioxidants are present in blood and other water-containing solutions in the body, while the fat-soluble antioxidants are actually transported within the LDL particles themselves.” The fat-soluble antioxidants get transported right into the body’s fatty tissues and, on board the LDL, into the artery walls, Dr. Frei explains.
Vitamin C also seems to have one other role to play in defeating atherosclerosis, says Dr. Frei. When an LDL particle exhausts its vitamin E, vitamin C can regenerate the vitamin E, thus renewing its ability to prevent atherosclerosis. This observation has been made only in the laboratory, he adds, but there’s no reason to think that it’s not also happening in people.
The exact amount of vitamin C you need to achieve these results is still unknown, says Dr. Frei, but many cardiologists are recommending taking somewhere in the range of 250 to 500 milligrams a day.
Folic Acid Fights Heart Disease
Although antioxidants are clearly the major nutrients involved in defending your body against atherosclerosis, folate (the naturally occurring form of folic acid) may also have an important role to play.
That’s because several years ago, researchers discovered that people who have elevated blood levels of homocysteine, an amino acid found in meats that can damage arterial walls and contribute to the development of atherosclerosis, frequently suffer from severe atherosclerosis and heart attacks in their twenties and thirties.
Some seem to have a genetic defect that makes their bodies unable to use homocysteine. But others seem to be suffering from deficiencies of vitamin B6, vitamin B12 or folate.
Researchers are still not certain what causes excess levels of homocysteine in the blood, but they’re beginning to figure out how to reduce them.
“Folate prevents the buildup of homocysteine,” says Frank M. Sacks, M.D., associate professor of medicine and nutrition at Harvard School of Public Health.
In one study, researchers from Tufts University in Medford, Massachusetts, the Clinical Research Institute of Montreal and the Hospital Hotel-Dieu, also in Montreal, worked with 150 men and women between ages 28 and 59 with heart disease. They found that homocysteine levels can be reduced by taking either 50 milligrams of vitamin B6 or 5,000 micrograms of folic acid every day.
Since these amounts are between 12 and 25 times the Daily Values of these vitamins, however, the researchers opted not to recommend such high doses until further studies reveal the long-term effects. (Vitamin B6 is already known to cause nerve damage in high doses.) Lower doses may be as effective, but clinical trials are ongoing, says Jacques Genest, Jr., M.D., director of the cardiovascular genetics laboratory at the Clinical Research Institute of Montreal, who led the study.
In the meantime, advises Dr. Sacks, “eat some spinach or take a regular multivitamin/mineral supplement.” That should help you meet the Daily Value of folic acid (400 micrograms) and help keep homocysteine levels low enough to prevent a big buildup to begin with.
| Prescriptions for Healing Although researchers now strongly suspect that low levels of vitamin E, beta-carotene and vitamin C may in fact put your body at increased risk for heart disease, most of these scientists are reluctant to recommend specific amounts of these nutrients that you should get from your diet or from supplements. There are two reasons, researchers say. One is that there have not been enough large-scale studies in which huge numbers of people are given a specific amount of a nutrient and then tested for the effect. The second is that the amounts each person needs to eat or take to achieve therapeutic levels may be different, since each person absorbs each of these nutrients in his own individual way. One researcher, however, has taken the bull by the horns. In a study published in Britain, Dr. K. F. Gey of the Institute of Biochemistry and Molecular Biology at the University of Berne in Switzerland analyzed a number of nutrient studies from around the world. He postulates that when taken as a whole, these studies suggest that to protect against heart disease, individuals should aim for the levels listed below for the major antioxidants: beta-carotene, vitamin C and vitamin E. Dr. Gey states that these nutrients should be received together through a balanced diet rather than through individual supplementation. Nutrient Daily Amount
Beta-carotene 10,000-25,000 international units Vitamin C 60-250 milligrams Vitamin E 60-100 international units
Several other nutrients also play roles in heart health. Because low levels of these nutrients seem to raise the risk of heart disease, most doctors recommend that people be sure to get the Daily Values of these nutrients through a well-balanced diet and, if necessary, a multivitamin/mineral supplement. Nutrient Daily Amount
Folic acid 400 micrograms Iron 18 milligrams Selenium 70-100 micrograms Zinc 15 milligrams
MEDICAL ALERT: If you have heart disease, you should discuss vitamin and mineral supplementation with your doctor. The recommendations for the antioxidants vitamin C and vitamin E
exceed the Daily Values of these nutrients. A wide range is recommended
for each vitamin because the exact amount consumed would vary from person to person. If you are taking anticoagulant drugs, you should not take vitamin E supplements. |
Meet the Fighting Trio
Aside from helping you to meet your folate requirement, a well-balanced diet that emphasizes vegetables may help prevent heart disease for other reasons as well.
Researchers have found that low levels of at least three elements—selenium, zinc and iron, generally found in meats, seafood, cereals and vegetables—seem to increase your risk of heart disease.
In a study in Denmark of nearly 3,000 men between the ages of 53 and 74, researchers found that those with the lowest levels of selenium in their diets increased their risk of heart disease by 55 percent. What’s more, the researchers suspected that close to 19 percent of the heart attacks among men in the study might in fact be caused by low levels of this nutrient.
The Daily Value for selenium is 70 micrograms. Most researchers agree, however, that you can take up to 100 micrograms daily without harm.
Zinc might also play a role in preventing atherosclerosis, researchers say. Laboratory studies at the University of Kentucky in Lexington indicate that zinc may be necessary to safeguard the heart’s arterial walls from the damage triggered by high blood pressure, high cholesterol and tobacco smoke, which sets the whole atherosclerotic process into motion.
Zinc is involved in repairing and fortifying any breaches in the cells lining the heart’s arteries. So it’s possible that zinc can help prevent atherosclerosis by keeping arterial walls in such good shape that cholesterol and fatty acids do not enter the artery walls to form artery-clogging plaque.
The Daily Value for zinc is 15 milligrams a day.
A third mineral that may help your body fight heart disease is iron. A study of more than 4,000 men and women, conducted by the Hyattsville, Maryland, branch of the Centers for Disease Control and Prevention under the auspices of the National Institutes of Health in Bethesda, Maryland, revealed that people who had adequate levels of iron in the bloodstream were less likely to die from cardiovascular causes than people who had lower levels. The researchers noted that the data also indicated that adequate levels of iron may be protective against coronary heart disease.
Other researchers, however, believe that high levels of iron may be associated with increased risk of heart disease. So the benefit of high iron intake is an unresolved, controversial question.
The Daily Value for iron is 18 milligrams.
