Objective: To assess the effects of continued feeding of nonhuman milks or formulas to young children during acute diarrhea on their treatment failure rates, stool frequency and amount, diarrheal duration, and change in body weight.
Methods: A total of 29 randomized clinical trials of 2215 patients were identified by computerized bibliographic search and review of published articles. Data were abstracted and analyzed using standard meta-analytic procedures.
Results: Among studies that compared lactose-containing milk or formula diets with lactose-free regimens, those children who received the lactose-containing diets during acute diarrhea were twice as likely to have a treatment failure as those who received a lactose-free diet (22% vs 12%, respectively; P < .001). However, the excess treatment failure rates occurred only in those studies that included patients whose initial degree of dehydration, as reported by authors, was severe, or that were conducted before 1985, when appropriate diarrhea treatment protocols were first widely accepted. Among studies of patients with mild diarrhea, all but one of which were completed after 1985, the overall treatment failure rates in the lactose groups were similar to the rates in the lactose-free groups (13% vs 15%). These results suggest that children with mild or no dehydration and those who are managed according to appropriate treatment protocols, such as that promoted by the World Health Organization, can be treated as successfully with lactose-containing diets as with lactose-free ones. The pooled information from studies that compared undiluted lactose-containing milks with the same milks offered at reduced concentration concluded that (1) children who received undiluted milks were marginally more likely to experience treatment failure than those who received diluted milk (16% vs 12%, P = .05), (2) the differences in stool output were small and of limited clinical importance, and (3) children who received the undiluted milk diets gained 0.25 SD more weight than those who received the diluted ones (P = .004). In addition, as with the previous set of studies, there were no differences in the pooled treatment failure rates between the respective groups in those studies of mildly dehydrated patients conducted after 1985 (14% vs 12%).
Conclusions: The vast majority of young children with acute diarrhea can be successfully managed with continued feeding of undiluted nonhuman milks. Routine dilution of milk and routine use of lactose-free milk formula are therefore not necessary, especially when oral rehydration therapy and early feeding (in addition to milk) form the basic approach to the clinical management of diarrhea in infants and children.