Zinc, Iron and Infectionstudies in children and women in Nepal
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Malnutrition in the form of underweight, stunting, wasting or micronutrient deficiency is prevalent in developing countries and has serious health consequences, particularly for children and women. Correction of micronutrient deficiencies has been perceived as one of the most cost effective ways to improve maternal and child health and development. Cultural and dietary practices as well as nutrient content of local foods may differ between regions. It is therefore important to describe micronutrient status in representative population samples in developing countries. Iron and zinc, two essential nutrients which we get mainly from animal source foods, are low in the diet of most of women and children of low and middle income countries because of limited food intake, consumption of a predominantly vegetarian diet and frequent infections. Zinc deficiency is thought to be widespread in these countries and successful replenishment of this single nutrient might reduce morbidity and mortality. Globally, diarrhea and pneumonia together cause almost one third of all deaths in children less than 5 years of age. The beneficial effects of preventive as well as therapeutic zinc supplementation in reducing diarrheal duration and severity are already established. Zinc is now included in the standard treatment protocol for diarrhea management. Clinical trials in low-income countries have also shown that zinc supplementation to healthy children may prevent the occurrence of childhood pneumonia. It is plausible that zinc also may have a therapeutic effect when given during an acute episode of pneumonia. This has been assessed only in a few trials and the results are conflicting. It has also been observed that zinc given for a relatively short period of time (~ 2 weeks) may protect against common childhood infections for up to 6 months beyond the period of administration. However, the results from the studies examining this “downstream” effect of zinc on prevention of infections are also inconclusive. We carried out a cross-sectional study in a representative sample of 500 nonpregnant women, 13-35 years of age in Bhaktapur, Nepal. Plasma was analysed for zinc and different biomarkers of iron status. The intake of various nutrients was estimated by dietary recalls. We also conducted a clinical trial where we enrolled 2,628 cases of community acquired pneumonia to measure the efficacy of zinc on the risk of treatment failure, the duration of the enrollment episode and whether or not short-term zinc supplementation reduced the incidence of infections for the subsequent 6 months. In addition to standard antibiotics for pneumonia, children were given zinc sulfate or placebo tablets (age <1 year: 10 mg, 1 year: 20 mg of zinc) for 14 days. From these two large community based studies in Nepalese women and children, we documented that zinc deficiency was very common and coexisted with iron deficiency and anemia. Although, the intake of iron predicted hemoglobin concentration, the intake of zinc was not correlated with plasma zinc concentration. Despite the high prevalence of zinc deficiency and the fact that we have previously demonstrated a beneficial therapeutic effect of zinc on diarrhea in this population, we found that zinc neither reduced the duration of World Health Organization defined pneumonia nor the risk of treatment failure. Nor did short-term zinc administration reduce the burden of diarrheal or respiratory illnesses over 6 months of follow up. Vomiting/regurgitation, which is a well-known side effect of zinc, was more common among children who received zinc than in those who received placebo. Our findings indicate that oral zinc may not have a role in the treatment of community acquired relatively mild pneumonia in children. Zinc deficiency was common in this community; however, anemia and iron deficiency was substantially less common than available national estimates. Iron deficiency explained only half of the total anemia prevalence suggesting that other causes of anemia may be prevalent in this community.
PAPER I: Chandyo RK, Strand TA, Ulvik RJ, Adhikari RK, Ulak M, Dixit H, Sommerfelt H. Prevalence of iron deficiency and anemia among healthy women of reproductive age in Bhaktapur, Nepal. European Journal of Clinical Nutrition 61, 262-269, February 2007. Full text not available in BORA due to publisher restrictions. The article is available at: http://dx.doi.org/10.1038/sj.ejcn.1602508PAPER II: Chandyo RK, Strand TA, Mathisen M, Ulak M, Adhikari RK, Bolann BJ, Sommerfelt H. Zinc deficiency is common among healthy women of reproductive age in Bhaktapur, Nepal. Journal of Nutrition 139(3): 594-597, March 2009. Full text not available in BORA due to publisher restrictions. The article is available at: http://dx.doi.org/10.3945/jn.108.102111PAPER III: Valentiner-Branth P, Shrestha PS, Chandyo RK, Mathisen M, Basnet S, Bhandari N, Adhikari RK, Sommerfelt H and Strand TA. A randomized controlled trial of the effect of zinc as adjuvant therapy in children 2-35 mo of age with severe or non-severe pneumonia in Bhaktapur, Nepal. American Journal of Clinical Nutrition 2010;91:1667–74. Full text not available in BORA due to publisher restrictions. The article is available at: http://dx.doi.org/10.3945/ajcn.2009.28907PAPER IV: Chandyo RK, Shrestha PS, Valentiner-Branth P, Mathisen M, Basnet S, Ulak M, Adhikari RK, Sommerfelt H and Strand TA. Two Weeks of Zinc Administration to Nepalese Children with Pneumonia Does Not Reduce the Incidence of Pneumonia or Diarrhea During the Next 6 Months. Journal of Nutrition 140(9): 1677-1682, September 2010. Full text not available in BORA due to publisher restrictions. The article is available at: http://dx.doi.org/10.3945/jn.109.117978