Although a healthy diet is a mainstay of cholesterol control, people typically can reduce their cholesterol only about 10 percent by changing what they eat. As a result, doctors routinely prescribe cholesterol-lowering drugs called statins.
However, a variety of studies suggest certain plant foods are especially good at lowering cholesterol. So a Canadian team put together a diet combining several of these to see what would happen.
"The reductions are surprising," said Cyril Kendall of the University of Toronto. "Most dietitians would not expect that sort of reduction through dietary means."
Whether most people would stick with such a diet is another matter, since it involves daily okra, eggplant and Metamucil, among other things.
Still, Kendall said his preliminary results suggest the diet works about as well as the older statin drugs that are still first-line therapy for people with high cholesterol.
Kendall presented the results of his approach, called the Portfolio diet, at a meeting in Miami Beach on Thursday of the American Heart Association. The research was sponsored by the Canadian government, the Almond Board of California and the food companies Unilever Canada and Loblaw Brands.
"This was a pretty impressive result," said Dr. Stephen Daniels of Children's Hospital Medical Center in Cincinnati. "However, the results need to be replicated. Can this be done in the real world or only in an experiment?"
The diet is based on a low-fat vegetarian regimen that emphasizes foods shown individually to be beneficial — soy, soluble fiber, plant sterols and almonds. Sources of soluble fiber include oats, barley, legumes, eggplant, okra and Metamucil. Some brands of margarine are high in plant sterols.
In the experiment, 25 volunteers ate either a standard low-fat diet or the Portfolio approach, while researchers watched the effects on their LDL cholesterol, which increases the risk of heart disease, and HDL, which lowers it. After a month, LDL levels fell 12 percent in those on the standard diet and 35 percent in those on the Portfolio diet. However, HDL levels were unchanged in people on the Portfolio diet.
Kendall said volunteers found the diet extremely filling, and several have stayed on it after the experiment finished.
"It appears that a Portfolio diet is effective at reducing cholesterol and coronary heart disease risk," he said.
Whether it truly is as good as a statin, though, remains to be seen. Those drugs have been proven to reduce the risk of heart attacks and death, while the diet has not been put to that test. And statins may also protect the heart in ways that go beyond their effect on cholesterol.
In the experiment, dieters got foods supplied by the researchers that are all available from supermarkets or health food stores. Every meal contained soy in some form, such as soy yogurt or soy milk.
A typical breakfast included oat bran, fruit and soy milk, lunch might involve vegetarian chili, oat bran bread and tomato, and a typical dinner was vegetable curry, a soy burger, northern beans, barley, okra, eggplant, cauliflower, onions and red peppers. Volunteers also got Metamucil three times a day to provide soluble fiber from psyllium.
On a 2,000-calorie daily diet, volunteers got two grams of plant sterols from enriched margarine, 16 grams of soluble fiber from oats, barley and psyllium, and 45 grams of soy protein. They also got 200 grams of eggplant and 100 grams of okra daily and 30 grams of raw almonds. Additional vegetable protein was provides by beans, chick peas and lentils.
In another report at the conference, researchers from Children's Hospital in Boston found that people who eat breakfast every morning are less likely to be overweight or show early signs of diabetes. Among the 2,831 volunteers, white men and women who ate breakfast daily were only half as likely to be obese as were those who ate it seldom or never. Black men were 35 percent less likely, but for reasons the researchers could not explain, breakfast was not linked with lower weight in black women.
Mark Pereira, who presented the data, said people who eat breakfast may be less likely to snack during the day, so they end up eating less.