This study attempted to define the possible contribution of zinc nutrition to immunocompetence and growth in severely malnourished infants. The effect of zinc supplementation was evaluated in marasmic infants during nutritional rehabilitation by using a controlled double-blind design in which 19 infants fed a zinc-fortified formula were compared with 20 infants fed the same non-supplemented formula. Evaluation of immunocompetence, growth, and zinc, copper, and iron status was performed on admission and at 30, 60, and 105 d of nutritional rehabilitation. Although energy intake was similar in both groups, the zinc-supplemented infants had significantly higher linear growth gain, and their immune function improved as demonstrated by conversion of their delayed hypersensitivity skin reactions, enhanced lymphoproliferative response to PHA, and increased salivary IgA concentrations. Thus, the use of a zinc-fortified formula during nutritional rehabilitation can prevent the development of zinc deficiency and improve growth and immune function.

Phagocytosis and bactericidal capacity of neutrophils were measured in 10 iron-deficient infants age 6-23 mo. All infants had hemoglobins less than 11 mg/dL with low saturation of transferrin and serum ferritin but were otherwise in good health. Neutrophil function and iron status were assessed at 0, 3-5, 15, 30, and 90 days of oral iron therapy. Phagocytosis was unaffected in iron deficiency and remained unchanged during therapy. Bactericidal capacity was severely impaired prior to treatment. After 3-5 days of ferrous sulfate administration, there was no significant improvement. At day 15 it returned to normal ranges and remained so at days 30 and 90. The sequence of events suggests that iron does not have a direct effect upon circulating neutrophils but, rather, that it is required during the development of neutrophils in the bone marrow.

No abstract

Zinc has been shown to be involved in many functions of the immune system. This study was conducted to examine the effect of zinc supplementation on phagocytic, fungicidal and metabolic activity of blood monocytes of marasmic infants during nutritional rehabilitation. A controlled, double-blind design was used in which 19 infants fed a zinc-fortified formula were compared with 20 infants fed the same, unfortified formula. Evaluation of phagocytic-fungicidal capacity, growth, zinc, copper and iron status was performed in both groups on admission and after 60 and 105 days of nutritional rehabilitation. Although energy, copper and iron intakes were similar in the two groups, a decrease in the number of infants able to phagocytose one or more Candida buds was observed after 60 days of zinc supplementation compared to admission (p < 0.03). No change in phagocytic ability was detected between admission and 60 days in the control group. The number of infants with depressed fungicidal activity increased significantly after 105 days of nutritional rehabilitation in the zinc-fortified group as compared to controls (p < 0.04). The number and duration of impetigo episodes was significantly greater in the group fed the zinc-fortified formula. These results suggest that zinc supplements at the RDA level may impair monocyte function.