Legumes in human nutrition - part 1

Peer-Reviewed / Manuscript (original contribution) received: January 02, 2020 / Revision accepted: March 30, 2020

Health aspects – part 1

Introduction

Legumes are the fruits or seeds of plants in the family of fabaceae (leguminosae). The most common ones are soybeans, garden peas and other types of peas, faba beans and other types of beans, lentils, sweet lupins, and chick peas. In Europe, peas, faba beans, sweet lupins, and soybeans are the most economically important ones. The Food and Agriculture Organization (FAO) uses the term pulses for the dried seeds (beans, peas, lentils and chick peas). Because of their high fat content soybeans and peanuts are also called oil seed legumes [1].

Most legumes should not be consumed raw. Some contain large amounts of protease inhibitors and lectins (phytohemagglutinins). A common way to inactivate these ingredients is heating, like toasting (of soybean meal), extrusion, baking, steaming, and cooking. Sufficient heating both inactivates adverse substances and, through denaturing (unfolding of molecule structures), improves the digestibility, especially of proteins.

All nutrients (proteins, fat, carbohydrates, resistant starch and fiber, minerals and vitamins, phytochemicals) may contribute to the effect of legumes on human metabolism, isolated or in combination [2]. Particularly the effect of soybeans may be further modulated by genetics (Asians versus Caucasians) or the product type chosen (whole foods versus isolated components) (cited in [2]).

Abstract

Legumes (soybeans, faba beans and other types of beans, peas, lentils, sweet lupins and chick peas) are rich in protein, complex carbohydrates and fiber as well as minerals. They are an important component of healthy dietary patterns emphasizing plant foods. Intake in Western populations is rather low. This review presents findings from meta-analyses and some individual studies on their impact on metabolic parameters as well as on disease risks, namely risk of metabolic syndrome and associated disorders, of cardiovascular diseases as well as cancer. There are many studies on the effect of soybeans. Non-soy legumes also decreased in intervention trials LDL cholesterol and blood pressure and improved in part glycemic control. Their intake as well as adherence to a Mediterranean diet were associated with a lower risk of coronary heart disease and cardiovascular diseases. The Mediterranean and other healthy dietary patterns were associated with a lower risk of diabetes mellitus type 2. Whether intake of non-soy legumes affects cancer risk has little been examined up to now.

Keywords: legumes, plant protein, metabolism, health

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