• Peanuts are a popular type of legume used for human consumption.peanut image by dinostock from Fotolia.com
  
  Legumes are flowering plants that produce seedpods with two distinct halves. According to the U.S. Department of Agriculture (USDA), the legume family (known scientifically as Fabaceae) contains more than 20,000 species, making it the third most populous family of flowering plants (behind Asteraceae and Orchidaceae). These legume species range from large tropical trees to tiny temperate herbs; and individuals use them in many different applications.
  
  

Human Consumption

• Humans regularly eat a wide array of legumes, including peanuts, peas, chickpeas, beans, soybeans and lentils. According to Oregon State University, legumes are rich sources of fiber, protein, essential micro-nutrients and low-glycemic-index carbohydrates (which means they have little effect on blood-sugar levels). They also contain other beneficial compounds, including essential fatty acids, folate, magnesium, potassium and lignans. By replacing foods in your diet that are high in saturated fats with legumes, you are likely to lower your risk of developing type 2 diabetes and cardiovascular disease, according to Oregon State.
  
  

Animal Consumption

• According to the VOA News website, some farmers feed legume plant leaves (like those from beans or alfalfa) to animals such as goats and cows. Like the seedpods of legumes, the leaves are loaded with nutrients, which are beneficial to animal health.
  
  

Agricultural Uses

• While some farmers grow legumes for plant and/or animal consumption, others grow legumes for a less apparent reason: to increase the soil quality of their fields. According to the VOA News website, growing legumes can help restore nitrogen to the surrounding soil, which is used up by other crops. This is because legumes generate their own nitrogen through the process of nitrogen fixation. The process relies on the presence of symbiotic bacteria, which pull nitrogen out of the air and convert it to ammonia. In addition, the roots of legume plants help hold soil together, preventing damage from strong winds and heavy rains, while the leaves provide shade for younger crops (to protect them from overexposure to heat and sunlight).
  
  

Medicinal Uses

• According to the USDA, drug companies use legumes in many pharmaceutical applications and are finding new uses continuously. For example, some companies extract a particular type of phytosterol--known as beta-sitosterol--from legumes to produce cholesterol-lowering medicine. Another example is the flavonoid compound rutin, which companies extract from jack beans. According to the Phytochemicals website, rutin is known for its strong antioxidant properties, and it can help strengthen capillaries and stabilize vitamin C levels.