Background: Current WHO guidelines on the management and treatment of diarrhea in children strongly recommend continued feeding alongside the administration of oral rehydration solution and zinc therapy, but there remains some debate regarding the optimal diet or dietary ingredients for feeding children with diarrhea.
Methods: We conducted a systematic search for all published randomized controlled trials evaluating food-based interventions among children under five years old with diarrhea in low- and middle-income countries. We classified 29 eligible studies into one or more comparisons: reduced versus regular lactose liquid feeds, lactose-free versus lactose-containing liquid feeds, lactose-free liquid feeds versus lactose-containing mixed diets, and commercial/specialized ingredients versus home-available ingredients. We used all available outcome data to conduct random-effects meta-analyses to estimate the average effect of each intervention on diarrhea duration, stool output, weight gain and treatment failure risk for studies on acute and persistent diarrhea separately.
Results: Evidence of low-to-moderate quality suggests that among children with acute diarrhea, diluting or fermenting lactose-containing liquid feeds does not affect any outcome when compared with an ordinary lactose-containing liquid feeds. In contrast, moderate quality evidence suggests that lactose-free liquid feeds reduce duration and the risk of treatment failure compared to lactose-containing liquid feeds in acute diarrhea. Only limited evidence of low quality was available to assess either of these two approaches in persistent diarrhea, or to assess lactose-free liquid feeds compared to lactose-containing mixed diets in either acute or persistent diarrhea. For commercially prepared or specialized ingredients compared to home-available ingredients, we found low-to-moderate quality evidence of no effect on any outcome in either acute or persistent diarrhea, though when we restricted these analyses to studies where both intervention and control diets were lactose-free, weight gain in children with acute diarrhea was shown to be greater among those fed with a home-available diet.
Conclusions: Among children in low- and middle-income countries, where the dual burden of diarrhea and malnutrition is greatest and where access to proprietary formulas and specialized ingredients is limited, the use of locally available age-appropriate foods should be promoted for the majority of acute diarrhea cases. Lactose intolerance is an important complication in some cases, but even among those children for whom lactose avoidance may be necessary, nutritionally complete diets comprised of locally available ingredients can be used at least as effectively as commercial preparations or specialized ingredients. These same conclusions may also apply to the dietary management of children with persistent diarrhea, but the evidence remains limited.