A study led by Hans Verhoef, a researcher at Wageningen University, the Netherlands, and the London School of Hygiene and Tropical Medicine, UK, and published in this week’s PLoS Medicine shows that supplementing young Tanzanian children with zinc -either alone or in combination with other multi-nutrients - does not protect against malaria.

Zinc helps to maintain a healthy immune system, and previous studies had shown a benefit of zinc in reducing diarrhea. Most African children are deficient in zinc, and in this study the authors wanted to investigate a possible role for zinc supplementation in protecting against malaria.

The authors randomly assigned 612 children from a rural area of Tanzania aged between 6 months and 5 years to receive daily oral supplements containing zinc alone, multi-nutrients without zinc, multi-nutrients with zinc, or no micronutrients (placebo) and found that the incidence rate of malaria in all four intervention groups was very similar (about 3 episodes a year). None of the supplements had any effect on malaria rates when compared to the placebo, even though the occurrence of zinc deficiency was strongly reduced by zinc supplementation in the trial.

In a further analysis, the authors suggested that multi-nutrient supplementation might be harmful as it increased the risk of malaria in children with iron-deficiency.

The authors say: “Despite a high prevalence of zinc deficiency, excellent compliance, and few drop-outs, we found no evidence from this trial that preventive zinc supplementation, alone or with multi-nutrients, reduced rates of febrile attacks of malaria.”

They add: “We have presented evidence that multi-nutrient supplementation may increase the risk of malaria in children with iron deficiency, strengthening earlier concerns about the safety of multi-nutrient supplementation in malaria-endemic areas, even in settings with good access to health care and appropriate treatment.”

The authors conclude: “when results from all trials are considered together, there is no evidence that zinc interventions can reduce the burden of malaria in African children.”

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Funding: This work was supported by the Netherlands Organisation for Scientific Research (NWO)/WOTRO [W93-413, WAO93-441], UNICEF, Cornelis Visser Foundation and Wageningen University (Interdisciplinary Research and Education Fund). HV is currently supported by the INSTAPA project, which receives funding from the European Union’s Seventh Framework Programme (FP7/2007) under grant agreement no. 211484. QuikRead tests and trimagnesium dicitrate were donated by Orion Diagnostica, Espoo, Finland and Jungbunzlauer, Ladenburg, Germany, respectively; supplements were manufactured and donated by Laboratory Medisan, Heerenveen, The Netherlands. The funders had no role in the design or conduct of the study, in the collection, analysis and interpretation of data, or in the preparation or approval of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

Citation: Veenemans J, Milligan P, Prentice AM, Schouten LRA, Inja N, et al. (2011) Effect of Supplementation with Zinc and Other Micronutrients on Malaria in Tanzanian Children: A Randomised Trial. PLoS Med 8(11): e1001125. doi:10.1371/journal.pmed.1001125

CONTACT:

Hans Verhoef

London School of Hygiene and Tropical Medicine/Wageningen University
Cell Biology and Immunology
P.O. Box 338
Wageningen, GLD 6700 AH
The Netherlands
+31 (0) 317-483922

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