A community-based randomized controlled trial of iron and zinc supplementation in Indonesian infants: interactions between iron and zinc.
BACKGROUND
Combined supplementation with iron and zinc during infancy may be effective in preventing deficiencies of these micronutrients, but knowledge of their potential interactions when given together is insufficient.


OBJECTIVE
The goal was to compare the effect in infants of combined supplementation with iron and zinc and of supplementation with single micronutrients on iron and zinc status.


METHODS
Indonesian infants (n = 680) were randomly assigned to daily supplementation with 10 mg Fe (Fe group), 10 mg Zn (Zn group), 10 mg Fe + 10 mg Zn (Fe+Zn group), or placebo from 6 to 12 mo of age. Venous blood samples were collected at the start and end of the study. Five hundred forty-nine infants completed the supplementation and had both baseline and follow-up blood samples available for analysis.


RESULTS
Baseline prevalences of anemia, iron deficiency anemia (anemia and low serum ferritin), and low serum zinc (< 10.7 micromol/L) were 41%, 8%, and 78%, respectively. After supplementation, the Fe group had higher hemoglobin (119.4 compared with 115.3 g/L; P < 0.05) and serum ferritin (46.5 compared with 32.3 microg/L; P < 0.05) values than did the Fe+Zn group, indicating an effect of zinc on iron absorption. The Zn group had higher serum zinc (11.58 compared with 9.06 micromol/L; P < 0.05) than did the placebo group. There was a dose effect on serum ferritin in the Fe and Fe+Zn groups, but at different levels. There was a significant dose effect on serum zinc in the Zn group, whereas no dose effect was found in the Fe+Zn group beyond 7 mg Zn/d.


CONCLUSIONS
Supplementation with iron and zinc was less efficacious than were single supplements in improving iron and zinc status, with evidence of an interaction between iron and zinc when the combined supplement was given.
Lind
Torbjörn
T
Department of Public Health and Clinical Medicine, Epidemiology, Umeå University, Umeå, Sweden. torbjorn.lind@epiph.umu.se
Lönnerdal
Bo
B
Stenlund
Hans
H
Ismail
Djauhar
D
Seswandhana
Rosadi
R
Ekström
Eva-Charlotte
EC
Persson
Lars-Ake
LA
D018798:Anemia, Iron-Deficiency / Q000188:drug therapy* / Q000453:epidemiology; D003153:Community Health Services; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D005293:Ferritins / Q000097:blood; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007214:Indonesia / Q000453:epidemiology; D007223:Infant; D019266:Iron, Dietary / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D010919:Placebos; D016896:Treatment Outcome; D015032:Zinc / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000172:deficiency*
D006454:Hemoglobins; D019266:Iron, Dietary; D010919:Placebos; D005293:Ferritins; D015032:Zinc