Abstract
Changes in iron status in normal subjects consuming a dehydrated ration were studied to assess whether polycythemia from the hypoxia of moderately high altitudes would induce iron deficiency. Data were collected on 10 subjects two months before exposure, four times during the 31 day period at altitude and one month after exposure. Mean dietary iron consumption was 30.8 ± 1.06 mg (mean ± SEM) per day over the duration of the study. Hematocrit and hemoglobin values rose significantly by day 18 at altitude and returned to pre-exposure levels by one month after exposure (p<0.01). Serum transferrin concentrations increased progressively over the 31 day period and returned to pre-exposure values by one month after exposure. No significant changes in transferrin saturation or serum ferritin were noted over the study phases. Further, no subject had serum ferritin values < 12 g l−1 during altitude exposure or while consuming the dehydrated ration before exposure. Lack of a decline in serum ferritin suggests that adequate amounts of iron were available from other sources to meet the polycythemic demand without depleting iron stores. It is unknown whether this iron was gained from an increase in iron absorption. The results indicate that with iron intake three times the RDA, polycythemia of altitude does not result in a state of iron depletion. Whether iron depletion or deficiency would result at intakes comparable to the RDA cannot be determined from this study.