Alfalfa (Medicago sativa) is perennial herb that belongs to the Fabaceae or legume family of plants. Alfalfa grows to around one metre in height and possesses leaves that look similar to trilobed clover leaves. Alfalfa produced purple flowers which mature into spiral-shaped seed pods. Alfalfa was found mainly in the Mediterranean and Middle East and was extensively cultivated by the Romans and Greek civilisations. However, since this time alfalfa has spread throughout the world where it is used extensively as a livestock feed crop. The medicinal properties of alfalfa are one of a general tonic. This relates to the very high nutrient content that the plant possesses. In particular alfalfa contains high concentrations of a number of vitamins including vitamin A, thiamine, pyridoxine, cobalamin, vitamin C, vitamin E and vitamin K. As well as containing high concentrations of vitamins, alfalfa may be a good sources of minerals. However, this is dependent on the mineral content upon which the alfalfa plant is grown.
As with soybeans, alfalfa also contains the isoflavones daidzein and genistein, although the levels are lower in alfalfa compared to soybeans. Many other legumes also contain isoflavones, but the soybean is the richest source. The flavonoid fomentation is also present. The isoflavones and flavonoids in alfalfa may confer antioxidant protection to the consumer, explaining some of the health benefits of the herb. Alfalfa possesses cholesterol lowering properties and this may relate to the presence of saponins. Researchers have suggested that plant saponins can decrease the absorption of cholesterol in the gut, although as dietary cholesterol is not able to alter plasma cholesterol levels, it is unclear how this mechanisms is able to function. It is perhaps more likely that the saponins are absorbed and then regulate metabolism of cholesterol in some way. The coumarins coumestans and medicagol are also present in alfalfa and along with the isoflavones and flavonoids may contribute to the antioxidant effects of alfalfa.