Legumes and grains have been used as food sources for thousands of years. Both are staple foods in cultures around the world, as they are less expensive than meat, poultry and fish, and when eaten together provide a complete protein essential for health.

Legumes and Grains

Legumes are plants that produce seeds or pulses. Common seeds and pulses used for food include beans, lentils, peas and peanuts. Similarly, grains, such as rice, maize (corn), millet, barley, buckwheat and rye, have long been cultivated for food use. Legumes are good sources of folic acid, iron and B vitamins, such as B1 and B6. Grains provide magnesium, calcium, potassium and chromium. Legumes and grains are high in fiber, which aids in bowel regularity.

Types of Legumes

The most common legumes for food use are beans, lentils, peas and peanuts. Types of peas include green peas, black-eyed peas, and green and yellow split peas. Lentils come in brown, green and red varieties. Other types of beans used for food include soybeans, mung beans and azuki (red) beans in Asia, fava beans and garbanzo beans in the Middle East and black beans, white cannellini beans, kidney beans, lima beans, navy beans and pinto beans in the Americas.

Types of Grains

Grains, such as wheat, oats and corn, are popular in Western countries, while in Asian countries, rice is a staple. Other grains include amaranth, buckwheat, barley, couscous, millet, quinoa, rye, spelt and teff. Quinoa is believed to be a complete protein, unique in the grain family, similar to soybeans in the legume family. Grains are low in the amino acid lysine, whereas legumes are high in lysine. Grains and legumes are complementary protein sources that can be combined to make a complete protein.

The Importance of Food Combining for Vegetarians

Consuming sufficient complete protein foods is especially important for vegetarians and vegans. While animal proteins, such as beef, chicken, eggs, pork and fish, contain complete protein, meaning they contain all essential amino acids, legumes, such as beans, do not contain complete protein (with the exception of soybeans). Vegetarians and others who wish to avoid eating animal products can combine legumes with grains to create a complete protein food necessary to maintain good health.