TUESDAY, Nov. 26, 2002 (HealthDayNews) -- New research confirms what we should already know: Diets low in saturated fats, high in omega-3 fatty acids and high in fruits, vegetables, nuts, and whole grains are the best for your heart.
"The information was scattered in various papers," says Dr. Frank Hu, lead investigator of the study and an associate professor of nutrition and epidemiology at Harvard School of Public Health. "We tried to put all the pieces together to solve the puzzle."
The study, which appears in tomorrow's issue of the Journal of the American Medical Association, identifies three "dietary strategies" that seem to be effective in preventing coronary heart disease (CHD).
"Such diets," the researchers write, "together with regular physical activity, avoidance of smoking, and maintaining a healthy weight, may prevent the majority of cardiovascular disease in Western populations."
"That's a huge statement by well-known researchers. That's the bottom line," says Samantha Heller, a senior clinical nutritionist at New York University Medical Center in New York City.
"What they're saying is stay away from saturated fat and cholesterol, stay away from meat, whole milk, mayonnaise, ice cream. Moving towards a plant-based diet is your best defense against not only heart disease, but obesity and diabetes as well," she adds.
The authors of the study, both professors at the Harvard School of Public Health in Boston, searched the MEDLINE database of medical literature for epidemiologic and clinical studies of dietary factors through May 2002. The authors ultimately examined 147 different studies and reviews for conclusions on diet and coronary heart disease prevention.
Three individual strategies emerged as the best for fighting heart disease. And they worked even better in combination.
The first is to substitute unsaturated fats for saturated and trans-fats. (Trans-fats are fats that have been altered, like those found in cookies, crackers, candy and margarine).
What does that mean to the average person?
"That means not eating red meat, whole milk, mayonnaise, ice cream and other whole dairy products," Heller says. "That has definitely been shown to decrease the risk of heart disease."
Eating meat or cheese interferes with the liver's ability to process fats and therefore raises cholesterol in the arteries.
The second strategy is to up your consumption of omega-3 fatty acids from fish oil or plant sources. You can get these fatty acids from eating fish regularly, and from consuming canola oil, soy bean oil, and flaxseed oil.
The third strategy is to consume a diet high in fruits, vegetables, nuts, and whole grains and low in refined grains.
The glycemic index (GI), which attempts to rank foods on how they affect blood sugar levels, is still controversial, Hu says. It may be useful to some degree in classifying starchy foods such as bread and potatoes but it is not useful for classifying other foods such as protein, fruits, and vegetables.
Similarly, the study authors found that the relationship between dietary fat and obesity is extremely controversial.
"The conventional wisdom is that high-fat diets lead to obesity and diabetes. This hasn't been supported by the scientific evidence," Hu says.
Calories in general may lead to obesity, but not just calories from fat. In fact, Hu adds, "there's more evidence that calories from carbohydrates, especially refined carbohydrates and sugars, could be more detrimental for obesity and diabetes."
Your best bet is to combine the three dietary strategies outlined in the report. "I can be a vegetarian and still eat a lot of white flour, processed food, and white chocolate and still be overweight," Heller says. "You want the effect of all three strategies. Nuts, seeds, legumes, vegetables, fruits, whole grains, and soy products contain chemical compounds like phytochemicals, antioxidants, vitamins and minerals that help fight disease of all kind. You're reinforcing your body's ability to stay healthy every time you eat a food like that. So why not?"
What To Do
For information on how to follow a healthy diet, visit the American Heart Association. The U.S. Department of Agriculture offers an online dietary assessment tool for you to assess your own eating habits.
