BioFe, Medical Food for Iron Deficiency is nutritional/Baker's yeast (Saccharomyces cerevisiae), expressing the Ferritin protein. Ferritin is an indispensable iron storage, transport and absorption protein normally produced at low levels by almost all living organisms. An illustrative example of the biology of the Ferritin/Iron complex is its presence in human breast milk, providing infants the natural biological iron required for rapid learning and development, without gastrointestinal upset. BioFe provides high level expression of Ferritin that is naturally complexed with iron during culture, is pasteurized, and dried.