Whole Grains and Prediabetes

One of the first clinical signs of developing diabetes is what is known as "impaired glucose tolerance." Simply put: after a standard blood glucose test, those who have a blood glucose level that is higher than normal, but lower than that of a person with diabetes, are considered to have impaired glucose tolerance. This often appears in combination with insulin resistance, in which the cells do not respond to the release of insulin. When both of these effects reach a certain level the combination is known as "prediabetes." Over one-third of those with prediabetes progress to Type 2 diabetes within ten years.

The good news is that there are ways to help prevent prediabetes from progressing to full blown diabetes, including improved diet, regular exercise, and weight loss. We know that the best diet for those with Type 2 diabetes is a Mediterranean-style diet, and one component in particular - whole grains - has been extensively studied for its effects on those with prediabetes or Type 2 diabetes.

A recently published study in the American Journal of Clinical Nutrition (2013; 97:179-87) adds to the research on fiber and focuses specifically on both developing prediabetes and the progression from prediabetes to diabetes. In a study lasting over 8 years, researchers in Stockholm, Sweden analyzed the diets of over 5,000 men and women and compared the levels of intake of whole grains of those who developed prediabetes or progressed to type 2 diabetes with those who did not.

They found that as compared to those who ate an average of about 30 grams or less per day, those who averaged eating nearly 60 grams of whole grains per day were about one-third less likely to progress from normal glucose tolerance to prediabetes or from prediabetes to diabetes. Specifically, those who ate the most whole grains and had normal glucose tolerance at the start of the study were 27% less likely to develop prediabetes than those who ate the least. Those with prediabetes at the start of the study were 29% less likely to progress to diabetes.

What this means for you

It's easy to get more whole grains in your diet. For example: one 1/2-cup serving of cooked brown rice or 1 slice of 100% whole grain bread contains about 16 grams of whole grains. Here are some guidelines for getting better quality fiber - whole grains - in your diet: Practical Starch Choices.

First posted: January 16, 2013