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PAPERS: Mohammad M Rahman, Sten H Vermund, Mohammad A Wahed, George J Fuchs, Abdullah H Baqui, and Jose O Alvarez Simultaneous zinc and vitamin A supplementation in Bangladeshi children: randomised double blind controlled trial BMJ 2001; 323: 314-318 [Abstract] [Full text]

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Which zinc?

David Potterton   (10 August 2001)

Vitamin A and Zinc Supplementation

Dominic Lea   (24 August 2001)

Which zinc? 10 August 2001
David Potterton, Medical journalist Therapy Weekly, London Send response to journal: Re: Which zinc?	This study reveals the importance of supplementation when the mineral is actually absorbed. Zinc is not well absorbed which is why there are so many zinc compounds available. For example zinc sulphate and zinc gluconate are notoriously poorly absorbed, whereas zinc orotate (50 per cent) and food state zinc (70 per cent) are among the best. This also explains why trials with zinc supplementation (eg for the common cold) often come to opposite conclusions. In this case the researchers have done well. They could probably do better if they used a well-absorbed zinc supplement. For long-term use they should add in copper 1mg to zinc 15mg.
Vitamin A and Zinc Supplementation 24 August 2001
Dominic Lea, Stage 3 Medical Student Department of Epidemiology and Public Health, The Medical School, University of Newcastle Send response to journal: Re: Vitamin A and Zinc Supplementation	Editor, The study by Rahman et al addresses a worthwhile aspect of vitamin A and zinc supplementation.(1) However, they have made certain conclusions relating to diarrhoea that are not fully supported by the evidence they present. Although giving zinc and vitamin A may well have a beneficial effect, in several instances the confidence intervals of the rate ratio span 1 which implies the results are not significant. We would like to suggest that only cautious inferences should be drawn from this data. Presenting figures for individual study groups would make interpreting the results easier. Including the combined supplement groups in the data for zinc and vitamin A obscures the independent effects of these interventions. This may have increased the power of the study but a comparison of zinc or vitamin A alone with the combination would have been valuable. We are confused with the values obtained for “person year risk” in tables 2 and 3; is this a typographical error? “Person day risk” would be more consistent with the number of subjects and length of follow up. We agree with Rahman et al about the public health potential of simultaneous zinc and vitamin A supplementation. However, further research, possibly with a larger sample population, is required to establish a working protocol. Dominic Lea, Emma Fletcher, Caroline Angit, Noor Abdullah, Neil Greening (Stage 3 Medical Students) Department of Epidemiology and Public Health, The Medical School, University of Newcastle upon Tyne, Newcastle NE2 4HH 1 Rahman MM, Vermund SH, Wahed MA, Fuchs GJ, Baqui AH, Alvarez JO. Simultaneous zinc and vitamin A supplementation in Bangladeshi children: randomised double blind controlled trial. BMJ 2001; 323: 314-318