Iron is an imperative mineral for growth and development. The body also uses iron to produce hemoglobin, myoglobin, certain hormones and connective tissues.
An iron-deficient diet does not cause obvious symptoms because the body uses its resources stored in muscles, liver, spleen and bone marrow. Only after consuming iron reserves in tissues and organs does anemia set in. Red blood cells become smaller and contain less hemoglobin.
Iron deficiency is rarely encountered if a balanced diet is maintained. However, it can occur in people who do not eat meat, fish or seafood at all, after bleeding or in case of gastrointestinal diseases that interfere with the absorption of nutrients. (National Institute of Healt/Iron/ Fact Sheet for Consumers)