Like most beans, kidney beans are rich in the best sort of fiber - soluble fiber - which helps to eliminate cholesterol from the body. They are a good source of folate, potassium, iron, manganese, copper and zinc. As a high-potassium, low-sodium food they help reduce blood pressure. Not only are they low in fat, but when combined with grains, beans supply high quality protein which provides a healthy alternative to meat or other animal protein. Kidney beans also contain protease inhibitors which frustrate the development of cancerous cells.