Those who actually eat plenty of whole grains have higher quality diets overall, according to a new study. But these folks are few and far between in the United States.

The October issue of the Journal of the American Dietetic Association cites that less than 5% of the 19- to 50-year-old Americans surveyed from 1999-2004 said they ate at least three servings of whole grains each day. During this period, there were no specific guidelines on how much whole grains consumers should be eating, according to Carol E. O'Neil of Louisiana State University in Baton Rouge and the author of the study. In fact, people were simply told to consume “several servings.” But in 2005, new Dietary Guidelines for Americans specified that three servings of whole grains daily was the optimal amount.

Getting enough whole grains-where the outer portion of the kernel has not been removed-is linked to reduced heart disease, stroke, Type 2 diabetes, obesity and certain types of cancer, although it’s not clear what the mechanism is behind their beneficial effects, O'Neil says.

She and her colleagues reviewed the survey data to assess the ties between whole grains intake and diet quality. Their analysis included 7,039 men and women age 19 to 50 and another 6,237 people age 51 and older.

On average, the younger group consumed less than two-thirds of a serving of whole grains a day, but the older group ate just more than three-quarters of a serving. The fraction of people who ate the most whole grains also consumed more fiber, healthy fats and vitamins and minerals, and ate less sugar, unhealthy fat and cholesterol.

Because the study looked at only one point in time, it cannot assess the health effects of the subjects’ eating habits, O’Neil says. “We can only say that consumption of whole grains is associated with improved nutrient intake or diet quality,” she says. “We know from previous studies that consumption of whole grains is associated with a generally healthier lifestyle.”

Despite the fact that Americans now have more specific information on how much whole grains they should eat, O’Neil says it’s unlikely that the percentage of people eating enough whole grains has changed much since the survey was conducted.