Consumption of chickpeas and plasma glucose - Diet Quality

Nutrition Research Newsletter, March, 2004

The consumption of carbohydrates that result in low postprandial glucose and insulin concentrations, known as low-glycemic index foods, has been associated with reduced rates of coronary artery disease and type 2 diabetes. The main legumes eaten by humans have in common starches that are slowly digested. In chickpeas, about one-third of the starch is amylase, which even after gelatinization, is resistant to rapid and total hydrolysis in the small intestine. The botanical structure of legumes may also be a contributing factor to their rate of digestion. The health benefits of eating legumes reportedly include improved glucose disposal through greater insulin sensitivity. It is possible, however, that the demonstration of reduced glucose and insulin responses to single meals may not translate into longer-term improved insulin sensitivity. The focus of the present study was a comparison of the short- and long-term effects of chickpeas on plasma glucose and insulin responses.

Nineteen middle-aged men and women participated in this randomized, crossover, open study with chickpea- or wheat-based foods eaten for 6 wk each. They were asked to avoid eating legumes during the study period. The 3 test meals, which were based on white bread (standard), chickpeas, or wheat, were separated by at least 1 wk, and no more than 2 wks. Each meal provided 50 g available carbohydrate containing ~42 grams starch plus 10 g sugars, 12 g protein, and <2 g fat and 10 g dietary fiber. The chickpeas had been cooked and drained, gently mashed, and prepared with 100 ml low-fat milk.

Dietary fiber was significantly higher with the chickpea diet than during the wheat-based period or at baseline. When compared with baseline nutrient composition, fatty acid and cholesterol intakes during the chickpea period were significantly lower, suggesting a shift in food choices due to the apparently satiating effects of the chickpeas. The foods were eaten across 3 meals; for example, bread made with chickpea flour was eaten at breakfast, canned chickpeas and biscuits made from flour were eaten at lunch, and canned chickpeas plus bread were eaten in the evening. Similarly, wheat-based cereals were eaten in the morning and the bread at the other two meals. On the final day of each dietary period, a 75-g glucose load was administered and blood samples were collected over 120 rains through an indwelling small catheter in a forearm vein.

Plasma glucose concentrations after the chickpea treatment differed significantly from those after the wheat and standard treatments at 30 min and 60 min. The results of the present study confirm that a low-glycemic index food such as chickpeas results in lower plasma glucose, insulin, and HOMA (an index of insulin sensitivity) responses after a single meal than after meals of similar, available carbohydrate content, derived from wheat-based or higher glycemic index foods. However, there was no evidence for improved insulin sensitivity with long-term chickpea treatment. These negative findings occurred despite substantial and significantly fewer glycemic and insulinemic responses after single meals of chickpeas than after single meals of wheat-based foods.

P. Nestel, M. Cehun, A. Chronopoulos. Effects of long-term consumption and single meals of chickpeas on plasma glucose, insulin, and triacylglycerol concentrations. Am J Clin Nutr 79:390-395 (February 2004) [Correspondence: P. Nestel, Baker Heart Research Institute, PO Box 6492 St Kilda Central, Melbourne 8008, Australia. E-mail: paul.nestel@baker.edu.au]