What the Study Showed
In this large study reported in the American Journal of Clinical Nutrition in 1999, women who followed a diet rich in whole grains reduced their risk for developing coronary heart disease.
How It Was Done
As part of the ongoing Nurses' Health Study, 75,521 healthy women between the ages of 38 and 63 were asked to complete a detailed dietary questionnaire three times over a 10-year period.
They were specifically asked how often they ate whole grains (wheat germ, dark bread, oatmeal, and so forth) and refined foods, such as white bread, pasta, and muffins. None of the women had heart disease or diabetes when the study started.
Why It's Important
This carefully designed trial provides some sound evidence to back up many a cardiologist's clarion call: "Eat right for your heart!" And the more whole grains, the better these researchers report.
Women who consumed the most whole grains--nearly three servings a day--had a more than 30% lower risk of heart disease than the women who consumed less than one serving a day. Part of what makes these results so powerful is that other risk factors for heart disease--smoking, being overweight, alcohol intake-were controlled for.
The following foods were especially protective: whole-grain breakfast cereals, brown rice, popcorn, and bran. A multitude of mechanisms may be responsible for the benefit of whole grains in these kinds of foods. They're rich in heart-healthy fiber, Vitamin E, and folate, and they also contain various antioxidants and nutrients whose value to cardiac health is not fully understood.
It's also worth noting that whole grains (unlike refined ones) tend to be digested and absorbed slowly, so there's less of an increase in blood sugar and associated insulin levels. Eating such low-glycemic index foods, according to researchers, can reduce levels of potentially heart-damaging LDL cholesterol. (Too much LDL cholesterol can lead to blocked arteries and an increased risk for heart attack.)
Date Published: 2/15/2000
Date Reviewed: 1/9/2012