Dietary fibre has been shown to have important health implications in the prevention of risks of chronic diseases. The objective of the present study was to determine the potential health benefits of legumes as a good source of dietary fibre. Six to ten local legumes were studied as follows: cowpeas, mung beans, pole sitao, chickpeas, green peas, groundnuts, pigeon peas, kidney beans, lima beans and soyabeans. The following studies were conducted: (a) mineral availability, in vitro; (b) glycaemic index (GI) in non-diabetic and diabetic human subjects; (c) the cholesterol-lowering effect in human subjects with moderately raised serum cholesterol levels. The highest Fe availability among legumes was for lima beans (9·5 (sem 0·1)) while for Zn and Ca, the highest availability was for kidney beans (49·3 (sem 4·5)) and pigeon peas (75·1 (sem 7·1)), respectively. Groundnuts have the lowest Fe (1·3 (sem 1·1)), Zn (7·9 (sem 1·3)) and Ca (14·6 (sem 2·8)) availability. Legumes are low-GI foods ( < 55), ranging from 6 (chickpeas) to 13 (mung beans). Kidney beans showed significant reductions for both total (6 %) and LDL-cholesterol (9 %), and groundnuts for total cholesterol (7 %; P < 0·05). We conclude that mineral availability from legumes differs and may be attributed to their mineral content, mineral–mineral interaction and from their phytic and tannic acid content; legumes are considered low-GI foods and have shown potential hypocholesterolaemic effects. The above studies can be a scientific basis for considering legumes as functional foods.
(Received May 22 2009)
(Revised August 24 2009)
(Accepted August 26 2009)
(Online publication October 14 2009)
Abbreviations: GI, glycaemic index