Estimation of Iron Physiological Requirement in Chinese Children using Single Stable Isotope Tracer Technique

Abstract

Objective: This study is to obtain precise data on iron physiological requirements in Chinese children using single stable isotope tracer technique.

Methods: Thirty boys (10.6 ± 0.2 years) and 27 girls (10.4 ± 0.2 years) were received oral 6 mg ⁵⁷Fe each day for 5 consecutive days. Venous blood samples were subsequently drawn to examine the change of total iron concentration and ⁵⁷Fe abundance at day 0, 14, 28, 60, 90, 180, 360, 450, 540, 630, 720. The iron physiological requirement was calculated by iron loss combined with iron circulation rate once ⁵⁷Fe abundance stabilized in human body.

Results: The iron physiological requirement was significantly lower in boys than those values in girls (16.88 ± 7.12 vs. 18.40 ± 8.81 μg/kg per day, P < 0.05). Correspondingly, the values were calculated as 722.46 ± 8.43 μg/day for boys and 708.40 ± 7.55 μg/day for girls, respectively. Considering nearly 10% iron absorption rate, the estimated average iron physiological requirement was 6.0 mg/day in boys and 6.2 mg/day in girls.

Conclusion: This study indicate that iron physiological requirement could require more daily iron intake in girls as compare with the values in boys having the same body weight. These findings would be facilitate to the new revised dietary reference intakes.

Keywords: Chinese children; Dietary reference intakes; Iron absorption rate; Physiological requirement; Stale isotope tracer.