Jennifer Lovejoy, PhD, Vice President, Clinical Development & Support:

It is well-documented that eating whole grains has a host of health benefits. Eating more whole grains like brown rice, 100% whole wheat breads and cereals, oatmeal, and buckwheat has repeatedly been shown to lower risk for heart disease, Type 2 (adult) diabetes, stroke and obesity. Whole grains have also been found to reduce risk of asthma, improve the health of your blood vessels, lower blood pressure, and reduce risk for colorectal cancer.

What has been less clear, however, how important it is to eat exclusively whole grain products and to minimize or avoid intake of refined grains. In fact, the current U.S. Dietary Guidelines only recommend that “at least half” the daily grain servings should come from whole grains. I believe this is largely because, at the time the Dietary Guidelines were written in 2005, there was little research evidence documenting specific harm from refined grains (products like pasta and bread made from white flour, white rice, etc). Of course we knew in 2005 that refined grains cause a greater spike in blood sugar than do whole grains, and that the refining process caused loss of fiber, vitamins, minerals, and other beneficial plant compounds. But most epidemiological, or population-based, studies of grains and health had not looked hard at the question of whether whole grains and refined grains have different health effects, or they had looked but not found any significant differences in outcomes.

In the November 2010 issue of the American Journal of Clinical Nutrition, however, researchers report for the first time that whole grain intake reduces belly fat (measured either as waist circumference or intra-abdominal, visceral fat by CT scan), while refined grain intake actually increases belly fat. The study included 2834 men and women aged 32-83 years from the Framingham Heart Study, a long-term study that looks at various factors that influence risk for heart disease. The results showed that people who eat 3 or more servings of whole grains per day have 10% less belly fat than those who eat less than one serving a day of whole grains. However, among people who ate 3 servings/day of whole grains but also ate 4 or more servings per day of refined grains, there was no benefit of the whole grains on belly fat. And, even after accounting for other lifestyle factors, higher refined grain intake was associated with bigger waist circumference.

This study is very noteworthy because it’s the first time research has demonstrated a specific effect of refined grains on increasing fatness, as well as reduction in the beneficial effect of whole grains when refined grains are consumed in the diet as well. The study’s authors conclude that “emphasis needs to be placed on the substitution of refined grains with whole grains rather than addition of whole grains to a diet already high in refined grains.” A good reminder to all of us on the importance of eating whole foods as nature intended!