Amaranth has been cultivated as a grain for 8,000 years. Amaranth is classified as a pseudeocereal; it is grown for its edible starchy seeds like cereals, but it is not from the same family as cereals such as wheat and rice. The yield of grain amaranth is comparable to rice or maize. It was a staple food of the Aztecs and an integral part of Aztec religious ceremonies.
The cultivation of amaranth was banned by the conquistadores upon their conquest of the Aztec nation. However, the plant has grown as a weed since then, so its genetic base has been largely maintained. Research on grain amaranth began in the United States in the 1970s. By the end of the 1970s, a few thousand acres were being cultivated. Much of the grain currently grown is sold in health food shops.
Raw amaranth grain is inedible to humans and cannot be digested because it blocks the absorption of nutrients. Thus it has to be prepared and cooked like other grains. In a 100 gram amount, cooked amaranth provides 103 Calories and is a moderate rich source of dietary minerals, including phosphorus, manganese, and iron. Cooked amaranth is 75% water, 19% carbohydrates, 4% protein, and 2% fat. According to Educational Concerns For Hunger Organization (ECHO), amaranth contains anti-nutritional factors, including oxalates, nitrates, saponins, and phenolic compounds. Cooking methods such as boiling amaranth in water and then discarding the water may reduce toxic effects.
Amaranth grain is high in protein and lysine, an amino acid found in low quantities in other grains. Amaranth grain is deficient in essential amino acids such as leucine and threonine, both of which are present in wheat germ. Amaranth grain is free of gluten, which makes it a viable grain for people with gluten intolerance.