Introduction

Consider it the "T-shirt and jeans" of the nutrition world: the simple, familiar advice to adopt a diet rich in fruits, vegetables, legumes, whole grains, fish, and poultry. But can focusing on foods such as these really pay off?

Results from a pair of studies conducted by two groups of Harvard researchers add weight to the evidence that diet does indeed matter. Both studies, recently reported in the American Journal of Clinical Nutrition, examined the effect of food choices on participants' risk of developing cardiovascular disease, the leading cause of death in the United States.

To examine the health impact of a high intake of fruits and vegetables, researchers used information on fruit and vegetable consumption obtained from more than 39,000 female health professionals participating in the ongoing Women's Health Study. The researchers divided the women into five groups based on how many servings of fruits and vegetables they ate each day. The occurrence of cardiovascular disease within each intake group was determined by tallying the number of participants who suffered a heart attack or stroke over a five-year period. Results showed that women who consumed anywhere from 4 to 10 or more servings of fruits and vegetables a day had a 20 to 30 % lower risk of cardiovascular disease when compared with those who ate an average 2.5 servings a day.

In a second study, researchers analyzed data from nearly 45,000 men in the Health Professionals Follow-Up Study. Using information from diet surveys completed by the men at the start of the study, the scientists identified two major dietary patterns of food consumption. One they labeled a "prudent" diet-high in fruits, vegetables, whole grains, fish, and poultry, and the other a "Western" diet-high in red meat, processed meat, whole-fat dairy foods, refined grains, and sweets. After eight years of study, the researchers reported that, as expected, the men who followed the prudent diet pattern were less likely than others in the study to develop heart disease.

A "heart healthy" diet includes a variety of foods

Both of these studies look at intake of broad categories of food, rather than individual nutrients. Given that few people hit the grocery aisles in search of say, vitamin C, folate, or fiber, but rather buy oranges, spinach, or whole wheat bread, this makes good sense. And, as the researchers in the latter study point out, people eat meals that include a variety of foods that can interact in complex ways. Research will continue into precisely what it is in healthful food that seems to lower disease risk. In the meantime, health benefits can accrue by satisfying a sweet tooth with fruit rather than with a donut, or by swapping lower-fat fish for a higher-fat steak.