Soy and other legumes: ‘Bean’ around a long time but are they the ‘superfoods’ of the millennium and what are the safety issues for their constituent phytoestrogens?

Abstract

The recognition that legumes and, in particular, soybeans provide not only an excellent source of vegetable protein but also contain appreciable amounts of a number of phytoprotectants has increased general awareness of their potential nutritional and health properties. Since the discovery that soybeans are one of the richest dietary sources of bioavailable phytoestrogens, this legume has been elevated to the forefront of clinical nutritional research. These natural 'selective oestrogen receptor modulators' have been shown to be bioactive. The recent approval by the Food and Drug Administration in the United States for a health claim for soy protein reducing risk for heart disease by its effects on lowering cholesterol levels has led to the increased awareness of the health benefits of soy protein. However, the presence of high levels of phytoestrogens in soybeans has also led to concerns over the potential safety of soy foods. This review will focus on the cardioprotective benefits of legumes and discuss the hypothetical concerns regarding the constituent phytoestrogens.