Heart of the Matter
Cholesterol & the heart-smart consumer: foods to eat, foods to avoid.
Cholesterol & the heart-smart consumer: foods to eat, foods to avoid.
A year ago, Alabama pediatrician Laura Sawaya-Cortez thought she knew just about everything there is to know about cholesterol-except her own numbers. "I didn't want to know," she now admits, since she suspected they were probably too high. Ten years earlier, when she went to a local cholesterol-screening program, her numbers were above normal. "But I was in my mid-twenties then and it wasn't something I worried about," she says. Last March, motivated by her family history, she finally had her numbers checked with a fasting blood test-and discovered that they were well into the danger zone.
You might think a doctor would follow her own doctor's advice. But when Sawaya-Cortez's physician suggested that she start taking a cholesterol-lowering statin drug, she said no. Or at least, not yet. Before she began a medication that she might have to take for the rest of her life, she wanted to see if she could bring the numbers down herself, following the familiar advice that many physicians give their patients. She and her husband cut way back on red meat. They started eating more fish and turkey and switched from whole milk to soymilk. They helped themselves to lots of fruits and vegetables. And within a few months her total cholesterol had dropped from 226 to 177, landing firmly in the the safe zone. Her LDL (bad) cholesterol was down an impressive 50 points, from 161 to 111. "Frankly, I was amazed. I wouldn't have thought it was possible."
Stories like hers might once have inspired Steven Peterson, 55, a business consultant in northern California. Like Sawaya-Cortez, the last thing he wanted to do was take drugs after he learned that his cholesterol numbers were through the roof. "I tried everything. Oats for breakfast. Soy protein smoothies for lunch. No red meat. Olive oil instead of butter. Nuts for snacks. When I read somewhere that broccoli sprouts might lower cholesterol, we actually started growing them in a window garden in the kitchen."
No luck. When Peterson went back to have his cholesterol rechecked after six months, it was slightly higher than before. He left the doctor's office with a prescription for Lipitor, one of the family of leading cholesterol-lowering drugs called statins.
Abnormal cholesterol levels remain at the top of the list of serious risk factors for heart disease. Based on the current guidelines, nearly 107 million Americans are now believed to have cholesterol levels high enough to put them in danger of heart disease and stroke. Some, like Peterson, may have to go on medication. But many others, like Sawaya-Cortez, could bring their numbers into line simply by adopting a healthier diet and finding time for a little more exercise.
Too many people aren't even giving it a try, experts say. Why bother with the hassle when all you have to do is pop a daily pill, people tend to think. And given how little time most physicians have to counsel patients about healthy eating these days-and how difficult it is to get people to change-many doctors are taking the easy way out and simply writing a prescription. "Dietary and lifestyle approaches have been all but abandoned," says Margo Denke, M.D., a clinical professor at the University of Texas Health Science Center in San Antonio, who in past years helped draft the nation's official cholesterol guidelines. "And that's really a shame."
It is a shame-for several reasons. First, the benefits of eating wisely go way beyond lowering cholesterol. In some studies, adopting a healthier diet has lowered heart-disease risk dramatically, even when cholesterol numbers don't budge. What's more, making a few changes to the menu may be easier than taking a daily pill for the rest of one's life. The latest generation of cholesterol medications, called statins, only work if you take them every day. Many people don't. Surveys find that after a year, as many as two out of three have stopped filling their prescriptions. And once the drugs are discontinued, especially if people's diets remain the same, cholesterol levels zoom back up.
And let's face it, many people with high cholesterol don't change the way they eat. It's not unusual to sit down to a hearty dinner with someone who boasts that because he's on a drug, he can eat anything he wants. "Wrong, wrong, wrong," says Scott M. Grundy, M.D., director of the Center for Human Nutrition at the University of Texas Southwestern Medical Center in Dallas, who helped formulate the latest National Cholesterol Education Program guidelines. "It's not a matter of either/or, of drugs versus diet. Taking cholesterol-lowering medication doesn't mean you can forget about diet. By eating a healthier diet, you can lower your risk even further. And if you're on medication, you may be able to get by with a lower dose."
What's on the menu?
It's been more than 50 years since researchers first linked diet, high cholesterol levels and heart disease, and you'd think the experts would agree on the healthiest menu. Alas, there's still plenty of controversy. Lately, in fact, nutrition researchers say there is no single ideal diet. "What we're beginning to understand is that there is no one-size-fits-all diet to lower heart-disease risk," says Robert Knopp, M.D., a leading cholesterol expert at the University of Washington in Seattle. "Different people respond to different diets in very different ways."
Part of the change in thinking stems from a more sophisticated understanding of cholesterol. "Fifteen years ago, all we looked at was total cholesterol," says Debbie Strong, dietitian at the Ochsner Clinic Foundation's Heart and Vascular Institute in Louisiana. Today it is known that LDL cholesterol (low-density lipoproteins) is especially harmful, because it tends to accumulate on blood vessel walls as plaque. Another form, HDL cholesterol (high-density lipoproteins), is beneficial, because it helps ferry the bad (LDL) cholesterol out of the body. Research has revealed that measures of triglycerides, a form of fat particles in the blood, are also linked to heart-disease risk. Today, LDL, HDL and triglyceride levels are considered far more important than total cholesterol.
And that's where evaluating diets has proved trickier than anyone imagined. Some diets, like very-low-fat regimens, are effective at bringing down LDL-cholesterol numbers, but they often lower beneficial HDL as well and raise triglycerides-a dangerous combination of negative effects. Higher-fat diets keep HDL from falling, but they usually don't lower LDL as far.
Yet while there is no single perfect diet, the experts do agree on a few universal basics. It's important to reduce saturated fats (the kind found in meat and non-skim dairy products) as well as hydrogenated fats, or trans fats. These fats trigger the body to churn out more cholesterol. According to Denke, saturated and trans fats probably account for 80 percent of the effect of diet on cholesterol levels. The actual cholesterol content of a food (dietary cholesterol) is not as important.
Also key is a diet abundant in fruits, vegetables and whole grains, says Joseph M. Keenan, a cholesterol expert at the University of Minnesota School of Medicine. The antioxidants and other phytochemicals they contain may help keep artery walls healthy. But even more important, many plant-based foods (such as oats, barley, legumes and pectin-containing fruits) are high in soluble fiber, which acts like a sponge in the digestive tract, drawing cholesterol out of the body. Whole-grain foods are also much lower than refined starches on the glycemic index (GI), and there's growing evidence that a low-GI diet may help improve cholesterol levels. In a 2005 study at Queen's University in Ontario, Canada, researchers compared volunteers who followed the typical food pyramid advice with others who adopted a stricter low-glycemic-load diet. Those on the low-GI diet lost more weight and saw greater improvements in their HDL cholesterol numbers.
Beyond these basics, there appear to be specific foods that may be particularly potent in reducing cholesterol. Studies have turned the spotlight on everything from oats and barley to soybeans, almonds, peanuts and blueberries. Some may help simply because they're high in soluble fiber; others may in fact contain substances that help give cholesterol levels an extra nudge downward. Research has shown that phytosterols and stanols, substances found at low levels in plants, can significantly lower LDL levels-prompting manufacturers to create versions of margarines and other foods with added phytosterols or stanols.
Whatever's on the menu, experts say, it's crucial to keep calories under control. Becoming overweight or obese is itself associated with abnormal cholesterol levels. And many studies have shown that people who shed even a small percentage of their excess body fat see improvements in cholesterol and triglyceride levels. "For someone who's seriously overweight, the best diet is the one that helps them lose weight, even if that just means controlling portion sizes," says Jay Mehta, M.D., Ph.D., professor of internal medicine at the University of Arkansas.
How low can you go?
Put all the best advice together into one diet plan and how much can you expect your numbers to improve? To find out, University of Toronto nutrition scientist David Jenkins recently created what he calls a "diet portfolio" of foods that have shown the most promise in reducing cholesterol-including tofu, oats, berries, almonds and margarines that contain sterols and stanols. To boost fiber, the menu includes soymilk whipped up with Metamucil (made from psyllium), as well as soy burgers and other meat substitutes designed to slash saturated fat. In a study published in 2003, Jenkins reported that some volunteers with high cholesterol lowered their LDL levels by 30 percent on the portfolio diet-very close to the kind of improvement typically seen with statin drugs. The same volunteers saw only an 8.5 percent drop when they followed a regimen that simply lowered saturated fat.
As impressive as those results are, physician Dean Ornish says he can do better. The Ornish diet, one of the pioneering heart-disease-prevention regimens, slashes not only saturated fat but all fat to a bare-bones minimum. Meat, fish, egg yolks and dairy products containing fat are banned. Even unsaturated vegetable oil is doled out in scant teaspoons. Ornish claims that his diet lowers LDL cholesterol by as much as 40 percent.
Although there is plenty to be learned from these studies, some experts have their doubts about the very optimistic findings. One reason the Jenkins diet may have recorded such dramatic improvements in LDL is that all the volunteers were a healthy weight, says Denke, who wrote an editorial accompanying the publication of the study in the American Journal of Clinical Nutrition. In general, she says, it's much easier to bring LDL down with dietary changes in people who are thin than in those who are fat.
Ornish-style very-low-fat plans raise similar concerns. True, they dramatically slash LDL cholesterol, but they often drag down protective HDL, as well, and raise triglyceride levels-an undesirable combination. And sticking to these plans is no picnic. After California-based physician Stephen Weiss was rushed to the hospital for an emergency angioplasty to clear out cholesterol-laden arteries leading to his heart, he immediately began following the Ornish diet. "Believe me, there's nothing like learning that you came this close to dying of a heart attack to motivate you to make some big changes," he says. But the longer he stayed on the diet, the worse he felt. "I was tired all the time, I looked bad and I felt worse," he remembers. Finally his doctor ordered him to add nuts, avocados, lean meats and more vegetable oil to his menu-shifting away from the extremes of the Ornish regimen and closer to the American Heart Association diet, which recommends about 30 percent of calories from fat (mostly monounsaturated or polyunsaturated varieties) and includes low-fat or nonfat dairy products, lean meats, fish and lots of fruits and vegetables. "Right away I began to look and feel better and my HDL went up."
Because he is also taking cholesterol-lowering drugs, Weiss can't say how much the diet has helped, but he's convinced that it's playing an important role. Now back to work as an internist with Kaiser Permanente Medical Group, he counsels patients to make doable changes-a little less red meat, more fish, an extra serving or two of vegetables and fruits, less sugar-rather than turn their diets upside down. He also tells them to be patient. Dietary changes may take from two to six months to show up in improved cholesterol numbers.
Some studies, in fact, show dramatic health benefits, even though cholesterol levels may show only minor improvement. The famous Lyon Diet Heart study in 1999, for example, showed that patients following a Mediterranean-style diet for 46 months had a 50 to 70 percent lower risk of recurrent heart disease, including cardiac death and nonfatal heart attack. The easy-to-follow diet included more fruit and vegetables, more fish, more poultry, more bread, cereals, beans and nuts. It had less red meat and moderate use of eggs and poultry. Butter and cream were replaced with olive oil and a canola-oil margarine high in alpha-linolenic acid.
Most doctors, in fact, recommend the mainstream American Heart Association diet, which has many Mediterranean influences, in part because it represents simple changes that most people can make and maintain. Studies show that, on average, sticking to the AHA regimen reduces LDL by about 8 percent. The way individuals respond to changed diet varies widely, however.
Why isn't clearly understood. "Obviously, someone who has been eating fast-food cheeseburgers every day for lunch and steaks for dinner is likely to get more dramatic results than someone who's already following a pretty healthy diet," says Weiss. And then, of course, there are genetic differences, which can trump even the healthiest diet. Just out of college, Hilary Lundquist, 22, learned that her total cholesterol was 230, enough to be of concern to her physician. "I was flabbergasted," she says. "I've always eaten lots of fruits and veggies, whole grains, lean protein and soy, low- and nonfat dairy, even flax."
Every little bit helps
Ultimately, Lundquist, whose parents both have high cholesterol, may have to go on medication to control her cholesterol, joining millions of Americans. Fortunately, the latest drugs have been shown to lower not only cholesterol but also the risk of heart disease. And new drugs in the pipeline, researchers say, are likely to be even more effective. One currently awaiting FDA approval, for example, has been shown to dramatically increase HDL levels at the same time that it helps people lose weight-a promising combination.
Even the best medications, however, won't replace the benefits of a healthy diet. One recent study showed that a 10-milligram dose of the statin drug simvastatin combined with 15 grams of soluble fiber a day had the same cholesterol-lowering power as a 20-milligram pill alone. "What that means is that we can often reduce the dose that people need by making a few changes in their diets," says family physician Daphne Miller, M.D., who also teaches nutrition at the University of California, San Francisco. "In other cases we can get them off the drugs entirely."
Thanks to statins, Steven Peterson has been able to keep his LDL cholesterol down. Thanks to a healthy diet, he's also been able to stick with a relatively low dose of the medication-saving money and avoiding side effects. "We stopped cultivating broccoli sprouts in the kitchen, I'll admit that," he says. "But it's still whole grains for breakfast, skim milk, meat only now and then, lots of salads, vegetables, whole-grain breads, nuts or fruit for snacks." Lately he's been considering switching to whole-wheat pasta and trying a new brand of yogurt enhanced with stanols. "The way I figure, every little bit helps."
-Peter Jaret is an award-winning science and health writer based in California.