n-3 Long–chain PUFAs reduce respiratory morbidity caused by iron supplementation in iron–deficient South African schoolchildren: a randomized, double–blind, placebo–controlled intervention

Abstract

ABSTRACT Background: Although iron supplementation in malaria–free areas "mostly reduces infectious morbidity, it can sometimes increase morbidity" from infections as a result of the dependence of pathogenic microorganisms on iron. Supplementation with n 3 (v–3) longchain polyunsaturated fatty acids (LCPUFAs) improved morbidity "in several human studies. However, information on the combined" effect of iron and n 3 LCPUFA supplementation on infectious morbidity is limited. "Objective: We determined whether n 3 LCPUFAs and iron supplementation," "alone or in combination, affected absenteeism and illness" in iron–deficient schoolchildren with low fish intake. Design: A total of 321 South African children (aged 6 11 y) with iron deficiency (ID) were randomly divided into 4 groups to receive 1) "iron plus placebo, 2) a mixture of docosahexaenoic acid and eicosapentaenoic" "acid (DHA/EPA) plus placebo, 3) iron plus DHA/EPA, or" 4) placebo plus placebo as oral supplements 4 times/wk for 8.5 "mo. Morbidity was recorded, and iron–status indexes were measured." The total phospholipid fatty acid composition of peripheral blood mononuclear cell membranes was analyzed in a subsample (n = 130). Results: Iron supplementation increased the number of days with "illness when all symptoms were considered (B: 0.87; 95% CI: 0.71," 1.03) as well as illness that was specifically caused by respiratory "symptoms (B: 1.45; 95% CI: 1.21, 1.70), whereas DHA/EPA reduced" the number of days with illness at school (B: 20.96; 95% CI: "21.33, 20.59). The increases caused by iron were reduced to the" levels seen in the placebo plus placebo group when iron was provided in combination with DHA/EPA as indicated by significant "iron 3 DHA/EPA interactions (both P , 0.001)." Conclusion: Iron supplementation increased morbidity (mostly respiratory) in iron–deficient South African schoolchildren with "low DHA/EPA intake, but when iron was given in combination" "with DHA/EPA, this effect was prevented. This trial was registered" at clinicaltrials.gov as NCT01092377. Am J Clin Nutr 2015;101:668 79.