A Microbiota-Directed Food Intervention for Undernourished Children

To the Editor: Chen et al. (April 22, 2021, issue) 1 compared the effects of a diet consisting of microbiota-directed complementary food (MDCF-2) with a sugar content of 29.8% with a diet consisting of ready-to-use supplementary food (RUSF) with a sugar content of 17.0%. Weight-for-length changes in z scores were small: 0.021 per week with MDCF-2 and 0.010 per week with RUSF in children whose z scores were initially 2.25 below standard measures. The difference in weight gain has little clinical significance: an additional 2 years of MDCF-2 supplementation would still be needed to shift the weight-for-length distribution toward the normal . . .