Absolute amount of iron absorbed in relation to the dose administered for the first administration (continuous line°) and the second administration (broken line⁺). Each dose was consumed by different subjects (n = 41). At doses of 60 mg and higher, the first and second dose absorptions differed significantly (P < .01). Data with different superscripts differ significantly (capitals: first dose; minuscule: second dose) The first dose absorption was predicted by the following model (R² = 0.450; P < .001): (Dose absorbed) = 0.816 × (dose administered)^0.678 ; whereas the second dose absorption (R² = 0.467, P < .001): (Dose absorbed) = 0.752 × (dose administered)^0.596. Absorption data are standardized to a plasma ferritin level of 15 µg/L.