**Abstract**

There is currently a trend in Western countries to increase the intake of plant proteins. In this chapter, the author explains that this is due to the beneficial physiological functions of plant proteins, based on the latest literature review and our own research results. Among plant proteins, soy protein has been reported to have many beneficial effects on the improvement and prevention of metabolic syndrome. This chapter outlines the excellent effects of soy protein on renal function [improvement of early symptoms of diabetic nephropathy], which is closely related to metabolic syndrome, and the effects of combining these effects as complementary medicine. In addition, recent findings about the anti-inflammatory and immune activation effects of soy protein as hydrolyzed peptides are outlined. A brief introduction of the recent results of other legume-derived proteins that have replaced soy proteins are also explained. By further deepening our understanding of the superior physiological functions of plant proteins, it is hoped that their use expands even further.

**Keywords:** soy protein, metabolic syndrome, chronic kidney disease, inflammatory disorder, pea protein, lupin protein, mung bean protein
