[Effects of iron supplementation with or without vitamin C on Zn and vitamin C status in iron-deficient university female students]

ABSTRACT

Iron deficiency and iron-deficiency anemia are one the most important health problems in the world. Iron supplementation can reduce both Zn absorption and plasma vitamin C concentration. In this study, effects of iron supplementation with and without ascorbic acid on Zn and vitamin C status in iron-deficient university female students have been studied. This study was a double-blind randomized clinical trial. Sixty non-anemic iron-deficient [NAID] girls were selected from 289 female students at Fatemeh Zahra [PBUH] dormitory, Shahid Beheshti University of Medical Sciences, Tehran. They were divided randomly into 2 groups, receiving either 50 mg/d elemental iron supplement [group I, intervention] or the supplement plus 500 mg/d ascorbic acid [group II, control] for 12 weeks. Blood analysis was made at the beginning and the end of the 6thand 12th weeks in the two groups. Hemoglobin and serum ferritin concentrations were measured using cell-counter and ELISA, respectively. Serum zinc and iron concentrations were analyzed by atomic absorption spectrophotometry and plasma vitamin C was analyzed by the 2, 4-DNPH method. The Student's t and repeated-measures tests were employed to analyze the data using the SPSS software. The serum zinc level was not initially significantly different between the two groups. It decreased from 80.9 +/- 4.2 to 68.9 +/- 2.7 and from 81.2 +/- 4.5 to 66.1 +/- 2.9 mg/dl by the 6th week in groups I and II, respectively [p<0.001], but by the 12th week it increased significantly to the preintervention value of 79 +/- 2.9 mg/dl [p < 0.01] in group I and, non-significantly, to 70.5 +/- 3.1 in group n. On the other hand, plasma vita D1 in C increased from 3.0 +/- 0.1 to 3.3 +/- 0.2 mg/l [NS] in group 1 and from 2.7 +/- 0.1 to 4.2 +/- 0.2 mg/l [p < 0.01] in group II by the 6th week. The incremental trend in group n continued between the 6thand 12th weeks [3.3 +/- 0.2 to 4.7 +/- 0.3 mg/l in group I, and 4.2 +/- 0.2 to 7.1 +/- 0.2 mg/l in group II; in both cases p < 0.001]. Serum ferritin and iron levels increased significantly in both groups [p < 0.01]. Iron supplementation with and without vitamin C in iron-deficient female students causes serum Zn reduction after 6 weeks. However, the decreasing trend stops after repletion of iron stores, the Zn level returning to the baseline value. Twelve weeks of iron supplementation does not seem to cause reductions in the serum zinc and plasma vitamin C levels in this age group