A new study in the August issue of the American Journal of Clinical Nutrition found people who ate more servings of whole grains had lower levels of fasting insulin, decreased levels of total cholesterol, lower LDL, or "bad," cholesterol levels, and a smaller waist-to-hip ratio.
The bad news is most people aren't eating enough whole grains, says study author Paul Jacques, chief of the nutritional epidemiology program for the U.S. Department of Agriculture's Human Nutrition Research Center on Aging.
"Whole grain consumption was very low," Jacques says. "The median was less than one serving per day." The recommended amount is three servings per day.
Jacques and his colleagues studied the diets of almost 3,000 individuals who have been participating in the Framingham Offspring study since 1971. Samples of their blood have been taken every three to four years since the start of the study. The average age of the study participants was 54 years old, and there were slightly more women than men.
The average whole grain consumption was only eight servings a week. By contrast, the intake of refined grains, such as those found in white bread, averaged 20 servings weekly.
Those who ate the most servings of whole grain foods also reported more healthy lifestyle behaviors, such as eating less meat, drinking less alcohol, taking multivitamins and eating more fruits and vegetables.
The researchers found that as more whole grains were consumed, insulin levels went down, as did cholesterol levels and the waist-to-hip ratio, which is a known risk factor for cardiovascular disease.
The insulin-lowering effect of whole grain foods was particularly strong for those who were already overweight or obese, probably because they tend to have the highest levels of fasting insulin to start with, Jacques explains.
The authors suspect some of the components of whole grains, like fiber or magnesium, help to improve insulin sensitivity and could play a role in preventing or managing Type II diabetes.
Also, a diet high in fiber may help with weight management, and a healthy weight is known to reduce the risk of diabetes, heart disease and cancer, says Molly Kimball, a sports and lifestyle nutritionist at the Elmwood Fitness Center at the Ochsner Clinic Foundation and Hospital in New Orleans.
Diabetes affects more than 17 million Americans, according to the American Diabetes Association. Six million of them don't know they have the disease.
So, how can you get more whole grains into your diet?
Kimball says consumers must be very savvy because many products that say wheat often contain refined grains. Check the ingredient list. If it says whole or 100 percent wheat, it's a whole grain. If it says enriched wheat, it's refined.
Also, she says, check the fiber content. Aim for 3 grams of fiber for a slice of bread or a serving of crackers and 5 grams of fiber for cereal.
However, she says, be sure to increase your fiber intake slowly to avoid bloating or cramping, and drink plenty of water.
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