NEW ORLEANS — A diet that includes regular consumption of non-soy legumes provides clinically meaningful lipid lowering in hypercholesterolemic individuals, a meta-analysis indicates.
The meta-analysis included 298 dyslipidemic adults not on lipid-lowering drugs who participated in 12 randomized controlled trials of at least 3 weeks' duration. The non-soy legume interventions resulted in a mean 10.8 mg/dL reduction in LDL cholesterol levels from a baseline of 172 mg/dL and a 13.5 mg/dL drop in total cholesterol from a mean 250 mg/dL at entry, Dr. Lydia A. Bazzano reported at the annual scientific sessions of the American Heart Association.
The cholesterol-lowering effects of soy beans, tofu, and other soy products have been well established in multiple large studies. The effects of non-soy legumes, however, are much less well studied. Since pinto beans, garbanzos, navy beans, lentils, and other non-soy legumes are consumed far more commonly than soy in Western countries, it was time to sift through the medical literature and identify the small but well-conducted randomized, controlled trials of non-soy legume dietary interventions in order to conduct a meta-analysis, explained Dr. Bazzano of Tulane University, New Orleans.
The quantities of non-soy legumes utilized in the studies ranged from roughly one-half cup of cooked beans or legume flours per day to every other day, she said.
Dr. Bazzano noted that the USDA food pyramid, now known as MyPyramid, suggests adults consume 3 cups of cooked beans per week. “We are very, very far behind that. Most people eat about a third of that,” she said.
Potential mechanisms by which eating non-soy legumes reduces cholesterol levels include binding of their soluble fiber to bile resins, flushing the cholesterol precursors from the body. The fermentation pattern of the legumes' insoluble fiber in the colon may impede production of cholesterol. Also, beans and lentils provide a feeling of satiety with minimal fat content, the physician noted.
The effects of legumes like pinto beans are less well studied than soy. ©Donald Erickson/