Can one diet help prevent heart disease, cancer, high blood pressure, obesity and diabetes? And will people eat it and enjoy it and leave the table satisfied? The answer to these questions increasingly appears to be yes.
This "miracle" diet called DASH (Dietary Approaches to Stop Hypertension) is available now in the grocery store. In fact, it has always been available. It is relatively low in fat, deriving less than 30 percent of daily calories from fat, but loaded with fruits and vegetables (eight to 10 servings a day) and grains (seven to eight servings). It also contains two to three daily servings of low-fat or nonfat dairy products but only modest amounts of lean meat, poultry and fish (two or fewer three-ounce cooked servings a day) and dried beans, nuts and seeds (four to five servings a week). No exotic foods, no supplements, no herbal concoctions.
And, unless most of your meals are from coffee shops and fast-food restaurants, it is not as challenging to live on the diet as many people think.
The most recent demonstration of its benefits is found in a study of 459 men and women with mild hypertension or borderline high-normal blood pressure who lived on just such a diet for eight weeks.
No changes were made in how much salt they consumed (three grams of sodium a day, which is about average in North America) or alcohol they drank or physical activity they undertook. In addition, their caloric intake was adjusted to keep their weight stable, even if they were overweight. They took no pressure-lowering drugs or vitamin-mineral supplements.
Remarkably, even though participants did not lose weight, reduce salt and alcohol intake or exercise more -- the usual prescription for controlling mild hypertension -- their blood pressures dropped significantly, as much as might be expected if they had taken medication to lower blood pressure. And the drop occurred within two weeks of starting the diet and persisted throughout the study.
As Dr. William M. Vollmer, a coordinator of the study, put it, "This means that people with mild hypertension can lower their blood pressure with more natural means and get off drugs or reduce the amount of medication they have to take."
Vollmer, of the Kaiser Permanente Center for Health Research in Portland, Oregon., also noted that "this diet is consistent with the disease-preventing diets that have been proposed by other groups." Other diseases that could help be prevented by such diet include cancer, diabetes and obesity.
The new findings also suggest that "foods, not supplements, are the way to go," Vollmer said. "We can't tell whether the good results were due to calcium, low fat or less protein combined with lots of fruits and vegetables," he said.
But the researchers did show that a low-fat diet that included dairy products and lots of fruits and vegetables was more effective in lowering blood pressure than a diet rich in fruits and vegetables that was not low in fat and contained few dairy products.
Previous studies that tested the ability of single nutrients to reduce high blood pressure have yielded contradictory results. Once again, it seems that a combination of nutrients and other beneficial substances found naturally in foods, rather than isolated vitamins or minerals, provides the optimal health benefit.
Many people are afraid of the current recommendation to eat even five servings a day of fruits and vegetables, so it is reasonable to assume that increasing to eight to 10 servings will seem a bother to most.
But look at how little food a single serving really is. It is half a cup of cooked fruit or vegetables, half a grapefruit, a medium apple or orange, a small banana, 6 ounces of fruit or vegetable juice, a quarter cup of dried fruit or 1 cup of raw leafy greens. Keep in mind that for most adult Americans, portion sizes are usually twice as big as what the government considers a serving.
Have fruit juice and perhaps a banana, berries or a wedge of melon with breakfast and you're off to a good start with two servings. Lettuce and tomato on your lunch sandwich, a side order of slaw and an apple or grapes for dessert or a snack add three more servings. A salad with dinner and one or two cooked vegetables would add four or more servings, and you have met the goal.
As for the grains, one slice of bread, half a cup of rice, pasta or dry or cooked cereal each equal a serving. Now, who eats just half a cup of pasta or cereal or even one slice of bread? You are more likely to have a cup of cereal (two servings), two cups of pasta (four servings), two slices of bread (two more servings) and a New York-size bagel (two to three servings), and you have met that goal, too.
The dairy products are easy: one glass of milk in cereal, a container of yogurt in the afternoon, and an ounce and a half of low-fat or nonfat cheese on a sandwich or as part of dinner will give you three servings and enough calcium to meet the daily recommended intake for adults.
Here is a sample dinner menu from the national study, known as DASH, for Dietary Approaches to Stop Hypertension: three ounces of baked cod or other kind of fish, one cup of rice, one-half cup broccoli, one-half cup of stewed tomatoes, a very small spinach salad, one small whole wheat dinner roll, a teaspoon of margarine and half a cup of melon balls. This adds up to these servings: one fish, three grains, four vegetables and fruits and one and one-half fat.
The main complaint the researchers received about such a meal was that it was too much food. The participants were not used to eating as much bulk as the diet provided and the meals often filled them up before they finished. This means that under ordinary circumstances, people might be inclined to eat less and, free from the strictures of a study that insisted on keeping weight steady, they would probably lose some weight.
As for how to go about learning to eat the DASH way, start slowly, making evolutionary, not revolutionary, changes in your usual diet. Begin to plan meals around the carbohydrates and vegetables instead of the protein-rich food.
For desserts and snacks, think low-fat and low-calorie: fruit,
pretzels, nuts, diet drinks, nonfat yogurt, perhaps a little
low-fat cheese and whole-grain crackers. And be moderate about
alcohol: one drink a day for women, two at most for men.