Dietary Iron Requirements

Inclusion Criteria: * Males and premenopausal females age 18-50 y * Previously participated in an iron stable isotope study or willing to consume an oral stable iron isotope and undergo a one-year equilibration period * Willing to refrain from iron-containing supplements for the duration of the study * Willing to refrain from tobacco smoking for the duration of the study * Have not donated blood 3 months prior to the start of the study and willing to refrain from donating blood for the duration of the study * Willing to have blood stored for future use * Able and willing to comply with study requirements and consent to participate Exclusion Criteria: * Females: pregnant or lactating or plans to become pregnant during the study period * Inability to provide informed consent and engage in informed consent procedures * Plans to relocate outside the study area