Human health and grain legumes

About ten years ago the U.S. Food and Drug Administration approved the health claim on soy foods for the prevention of high cholesterol, confirming the outcomes of numerous clinical studies conducted all over the world. At present, a similar health claim is pending in the European Union. Detailed studies have shown that the proteins have a predominant role in the cholesterol-lowering activity of soy (1). Since most legume proteins have considerable sequence homology, several groups, including ours, have undertaken studies on these vegetables. The most investigated are bean (a term indicating several species of the genera Phaseolus and Vigna), pea, faba bean, chickpea and lupin. Numerous experimental studies (2) in different animal models and a few clinical studies are available, which have indicated interesting pharmacological activities, against hypercholesterolemia, hypertension and hyperglycemia. Besides proteins, other nutraceuticals in legumes are resistant starch, soluble fibers, alpha-galactosides, unsaturated fatty acids (including alpha-linolenic acid) and antioxidant polyphenols. In addition, legumes also contain relevant amounts of macro and micro-elements and vitamins. Our attention was primarily focused on lupin whose composition is very similar to soy (high protein content, reduced presence of starch, relatively high concentrations of alpha-linolenic acid). Experimental studies in a rat model of hypercholesterolemia (3) and in a rabbit model of the atherosclerotic plaque, and a double-blind clinical study on moderately hypercholesterolemic patients have shown interesting activities. Another clinical study performed in Australia has shown, instead, a potential hypotensive activity (4).