The randomised controlled trial – published in JAMA’s Archives of Internal Medicine – backed the use of legumes to help lower the glycemic index (GI) of foods, adding that increasing legume consumption by at least 1 cup per day improved both glycemic control and reduced calculated coronary heart disease (CHD) risk scores.
“Legumes, including beans, chickpeas, and lentils, are among the lowest glycemic index (GI) foods and have been recommended in national diabetes mellitus (DM) guidelines,” explain the researchers – led by Dr David Jenkins from the University of Toronto, Canada. “Yet, to our knowledge, they have never been used specifically to lower the GI of the diet.”
As a result, the team decided to study how a low GI diet, with a legume focus affected the health of people with diabetes.
The 121 participants were randomised to receive either a low-GI legume diet that encouraged patients to increase eating legumes, or to increase insoluble fibre by eating whole wheat products for three months.
Jenkins and his colleagues found that the legume focused diet resulted in a better glycemic control and greater reductions in the estimated risk of heart disease than the fibre focused diet.
The team revealed that the legume-focused diet reduced hemoglobin A1c (HbA1c) – a measure of glycemic control – by -0.5% and the high wheat fibre diet reduced HbA1c values by -0.3%, while the reduction in heart disease risk on the legume diet was -0.8%,.
"In conclusion, legume consumption of approximately 190 g per day (1 cup) seems to contribute usefully to a low-GI diet and reduce CHD risk through a reduction in blood pressure," write the authors.
Jenkinks said support for the use of legumes in food products should be supported in both ‘traditional bean-eating communities’ and the Western diet – “even if the effect on glycemia is relatively small, given the magnitude of the problem and the need for acceptable dietary options, especially those options that may also have a BP and cardiovascular advantage."
Source: Archives of Internal Medicine
Published online ahead of print, doi: 10.1001/2013.jamainternmed.70
“Effect of Legumes as Part of a Low Glycemic Index Diet on Glycemic Control and Cardiovascular Risk Factors in Type 2 Diabetes Mellitus. A Randomized Controlled Trial”
Authors: David J. A. Jenkins, Cyril W. C. Kendall, Livia S. A. Augustin, Sandra Mitchell, Sandhya Sahye-Pudaruth, Sonia Blanco Mejia, et al