Beans 'incomplete,' but still good for you

Q. Why do registered dietitians recommend beans as a protein source when they are considered an incomplete protein?A. Beans offer many advantages as a protein source. They are considered "incomplete" or "low biologic value" because content of one or more particular amino acids (the building blocks of protein) is low. However, grain products such as bread, rice, pasta and tortillas have plenty, and beans supply the amino acid lacking in grains.Evidence now shows that you don't have to eat the beans and grains in the same meal; as long as you get a few servings of grains throughout the day, you will get complete protein over all.Beans are recommended because they are top sources of dietary fiber, which can lower blood cholesterol levels and may reduce risk of colorectal cancer. They're also excellent sources of many of the nutrients lacking in typical U.S. diets, including potassium, vitamin B-6 and magnesium, as well as natural plant compounds that are powerful antioxidants.Beans are a great source of folate, protecting against birth defects when consumed before and during pregnancy and keeping our DNA healthy to lower cancer risk. About a third of the starch in beans is called "resistant starch," which is fermented by our normal gut bacteria to produce butyrate, a compound that seems to promote healthy colon cells less likely to develop into cancer.Beans are also among the most economical and environmentally friendly forms of protein. bull; Provided by the American Institute for Cancer Research. More about the group and its New American Plate program at aicr.org.