Americans should bulk up on whole grains like oatmeal, barley and brown rice to help lower their risk of clogged arteries, heart attacks and strokes, according to researchers.

In a review of seven major studies, the researchers found that higher whole grain intake was consistently linked to a lower risk of heart disease and stroke. On average, adults who ate 2.5 servings of whole grains per day were nearly one-quarter less likely to develop cardiovascular disease than their peers who rarely consumed whole grains.

Whole grains are believed to benefit the heart in a number of ways. The fiber and other nutrients in whole grains may help lower cholesterol, blood sugar and insulin levels, as well as improve blood vessel functioning and reduce inflammation in the circulatory system.

Yet surveys show that few Americans get the recommended three servings of whole grains per day, according to the authors of the new study. More than 40 percent of U.S. adults say they eat no whole grains.

“Many consumers and health professionals are unaware of the health benefits of whole grains,” lead study author Dr. Philip B. Mellen, of Wake Forest University in Winston-Salem, North Carolina, said in a statement.

Some may also be confused about what exactly constitutes a whole grain. Whole grains contain three components: bran and germ, which are rich in fiber and nutrients, and an endosperm, which contains starch and protein. Highly processed grains, like white bread or snack foods made from white flour, are stripped of the bran and germ.

In contrast, whole grains - such as oats, barley, whole wheat, brown rice and quinoa - retain more of the nutrient-dense bran and germ.

Based on these latest findings, Mellen and his colleagues think health professionals should “redouble” their efforts to get people to eat more whole grains.

They report the results in the online edition of the journal Nutrition, Metabolism & Cardiovascular Diseases.

For the study, the researchers pooled data from seven major studies involving more than 285,000 men and women who were followed for 6 to 15 years. Overall, those who ate the most whole grains were less likely to suffer a heart attack or stroke, or die of cardiovascular causes.

This was true when other health factors, like overall diet, exercise, weight and smoking habits, were taken into account.

“Years ago, scientists hypothesized that the higher rates of chronic diseases we have in the West, including heart disease, are due, in part, to a diet full of processed foods,” Mellen said.

This idea has been born out, he added, in the lower rates of obesity, High cholesterol and heart problems seen in people who opt for whole grains.

SOURCE: Nutrition, Metabolism & Cardiovascular Diseases, online May 9, 2007.