Tag Archives: beans

Legumes and Whole Grains: Any Role in Diabetes?

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.

Gluten Intolerance

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. 

Glycemic Index

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.


Filed under Fiber, Fruits, Grains, legumes, Prevention of T2 Diabetes, Vegetables

Do Beans and Peas Affect Glucose Control in Diabetics?

Beans and peas improve control of blood sugar in diabetics and others, according to a recent report from Canadian researchers.  The effect is modest.

Dietary pulses are dried leguminous seeds, including beans, chickpeas, lentils, and peas.  Pulses fed to healthy volunteers have a very low glycemic index, meaning they don’t cause much of a rise in blood sugar compared to other carbohydrates.  They are loaded with fiber and are more slowly digested than foods such as cereals.   

Investigators examined 41 clinical trials (1,674 participants) on the effects of beans and peas on blood glucose control, whether used alone or as part of low-glycemic-index or high-fiber diets.  Eleven trials looked at the effect of beans and peas alone, with the experimental “dose” averging 1oo g per day (about half a cup).  The article doesn’t specify whether the weight of the pulse was the dry weight or the prepared weight.  I will assume prepared.

Pulse given alone or as part of a high-fiber or low-glycemic index diet improved markers of glucose control, such as fasting blood sugar and hemoglobin A1c.  The absolute improvement in HgbA1c was around 0.5%.  Effects in healthy non-diabetics were less dramatic or non-existent.

My Comments

This study was very difficult  for me to digest.  The researchers lumped together studies on diabetics  and non-diabetics, using various doses and types of pulses.  No wonder they found “significant interstudy heterogeneity.” 

Cardiovascular disease is common in diabetics.  I’m aware of at least one study linking legume consumption with lower rates of cardiovascular disease.  I was hoping this study would answer for me whether I should recommend legumes such as peas and beans for my type 2 diabetics.  Beans and peas do represent a low glycemic load, which is good.  But I think I’ll have to keep looking for better-designed studies.

Steve Parker, M.D. 

Reference:  Sievenpiper, J.L., et al.  Effect of non-oil-seed pulses on glycaemic control: a systematic review and meta-analysis of randomised controlled experimental trials in people with and without diabetesDiabetologia, 52 (2009): 1,479-1,495.  doi: 10.1007/s00125-009-1395-7

Comments Off on Do Beans and Peas Affect Glucose Control in Diabetics?

Filed under Carbohydrate, Fiber, Prevention of T2 Diabetes