Expert nutrition panels consistently recommend whole grains and legumes for people with diabetes. Why? And do these foods affect development of diabetes? I found a pertinent scientific review article on the subject from 2004 in the European Journal of Clinical Nutrition. Here are some pertinent quotes from the summary:
Epidemiological studies strongly support the suggestion that high intakes of whole grain foods protect against the development of type II diabetes mellitus (T2DM). People who consume approximately 3 servings per day of whole grain foods are less likely to develop T2DM than low consumers (<3 servings per week) with a risk reduction in the order of 20-30%.
The role of legumes in the prevention of diabetes is less clear, possibly because of the relatively low intake of leguminous foods in the populations studied. However, legumes share several qualities with whole grains of potential benefit to glycaemic control including slow release carbohydrate and a high fibre content. A substantial increase in dietary intake of legumes as replacement food for more rapidly digested carbohydrate might therefore be expected to improve glycaemic control and thus reduce incident diabetes. This is consistent with the results of dietary intervention studies that have found improvements in glycaemic control after increasing the dietary intake of whole grain foods, legumes, vegetables and fruit.
. . . it is cereal fibre that is largely insoluble [rather than soluble fiber] that is associated with a reduced risk of developing T2DM.
Thus, there is strong evidence to suggest that eating a variety of whole grain foods and legumes is beneficial in the prevention and management of diabetes. This is compatible with advice from around the world that recommends consumption of a wide range of carbohydrate foods from cereals, vegetables, legumes and fruits both for the general population and for people with diabetes.
A major protein in wheat is gluten. The last few years have seen the popular emergence of gluten-free this and gluten-free that. The idea is that gluten causes a variety of gastrointestinal, immunologic, and other problems, so wheat products should be avoided. Certainly they should be avoided in people with celiac disease, a well-established medical condition. I follow a few paleo blogs and know that grains and legumes are not part of that way of eating: the paleos say we are not evolved optimally to process them.
If legumes or wheat or other grains cause problems for you, don’t eat them. They have no essential nutrients that you can’t get elsewhere.
In my quest to develop a healthy Diabetic Mediterranean Diet, I’m finding that grains—compared to nearly all other carbohydrate-containing food groups—tend to have a higher glycemic index (GI). A low GI is 55 or less. High GI is 70 or greater. Grains in general raise blood sugar levels higher than many other sources of carbohydrates. But this is highly variable and depends partially on preparation of the grain. Whole grain products have a lower GI than highly processed counterparts. For instance, white bread has a GI of 70; whole wheat bread 67. Regular spaghetti is 38. Table sugar’s GI must be sky high, right? No, its just 61. A baked potato is a whopping 85.
Beans have a GI around 30 or 40. And they pack a lot more fiber per serving. For a diabetic struggling to keep blood sugars under control, which is a better choice: grains or legumes? I’m leaning towards legumes and other components of a low-glycemic-index diet.
Steve Parker, M.D.
PS: [Before you correct my GI numbers, please note I’m aware that various GI lists don’t agree with each other.]
Reference: Venn, B.J. and Mann, J.I. Cereal grains, legumes and diabetes. European Journal of Clinical Nutrition, 58 (2004): 1,443-1,461.