The ideal zinc preparation in the management of acute diarrhea in children.

Sir,

The role of zinc in acute diarrheal disease in children has been conclusively proven beyond any doubts by numerous trials.[1] In fact, the Indian Academy of Pediatrics, World Health Organization (WHO) and United Nations Children's Fund have already approved and recommend its usage as an adjunct to oral rehydration therapy (ORT) in treatment of acute diarrhea in children.[2] Though zinc is known to influence intestinal ion transport, the exact mechanism has not been fully established. In-vitro studies have shown zinc to inhibit cAMP-induced, chloride-dependent fluid secretion by inhibiting basolateral potassium (K) channels, which can explain its role in secretory diarrhea.[2] Zinc has also been found to stimulate an immune response, inhibit toxin-induced cholera in-vitro, improve the absorption of water and electrolytes, improve regeneration of the intestinal epithelium and increase the levels of brush border enzymes. It is also a cofactor for numerous metalloenzymes required for normal cellular functions.[2] The aforesaid functions of zinc compel us to believe that multiple mechanisms may be involved in reducing stool output in pediatric diarrhea.

Thus, the need for zinc in diarrhea has increased its prescription in India.[3] However, there is wide variation with respect to the formulation and combination of zinc prescribed. Surprisingly, “zinc plus multivitamins” syrup is frequently prescribed during acute diarrhea, which is not rational. The choice of “zinc plus multivitamins” might be due to the general belief of coexisting micronutrient deficiencies in diarrhea. However, contrary to the logic, it carries several disadvantages such as the preparation is hyperosmolar due to the high concentration of various micronutrient solutes. These increase the possibility of osmotic diarrhea that can cause paradoxical worsening. The presence of vitamin C and magnesium in the preparation plays a major role in this regard.[4] Moreover, multivitamin syrups contain less than recommended doses of elemental zinc per teaspoon (usually around 5 mg elemental zinc/5 ml); hence large doses may be required. In addition, there is a higher risk of vomiting and poor patient acceptability,[5] increase in the cost as compared with zinc only preparations. Further, there is no scientific evidence that “zinc plus other micronutrients” is better than “zinc alone” in treatment of diarrhea in children.[16] Management of malnourished children with diarrhea should be individualized as they may require intravenous micronutrients during the acute phase. WHO recommends “zinc only” syrup or tablet and not any zinc plus multivitamin combination as an adjunct to ORT in acute diarrhea.[7] For infants less than 6 months, 10 mg of elemental zinc per day and for children above 6 months, 20 mg of elemental zinc per day is recommended for 10-14 days.[7] Though zinc sulfate is recommended, zinc acetate and gluconate can also be used.[2] Zinc sulfate tablets may be dispersed in breast milk, in oral rehydration solution or in water on a small spoon.[7] Both syrups and tablets are equally effective and can be selected according to ease of administration.

To conclude, children should receive “zinc only” tablet or syrups during the acute phase of diarrhea. The combination of “zinc plus multivitamins” is irrational and should be avoided in the management of acute diarrhea. Multivitamins can be administered after diarrhea resolves, if required.