Relationship between frequency of yogurt consumption at 1 year of age and development at 3 years of age: The Japan Environment and Children's Study.

backgroundMultiple observational studies have demonstrated the health benefits of yogurt, which are considered due to yogurt's positive effects on the gut microbiota. It is also known that the intestinal microbiota is associated with cognitive and emotional functions. Although the intake of probiotics has been reported to improve neurodevelopmental symptoms in children, no large-scale studies have examined the association of yogurt consumption in early childhood with later neurodevelopmental status. In this study, we examined the association between frequency of such consumption at 1 year of age and the children's subsequent neurodevelopmental status.

methodsWe studied children's dietary consumption of yogurt at age 1 year and their neurodevelopment at age 3 years from data gathered from70,276 mother-child pairs enrolled in the Japan Environment and Children's Study. We collected data from pregnant women whose consent was obtained after the study was explained to them at participating facilities in the target area. Frequency of yogurt consumption was categorized into 0, 1-2, 3-4, and ≥ 5 times/week based on a questionnaire about the child's diet completed by the mother. Developmental delay was assessed using the Ages and Stages Questionnaires, Third Edition (ASQ-3™) in five domains: communication, gross motor, fine motor, problem solving, and personal-social. Using the results of the group that did not consume yogurt as a reference, multivariate logistic regression analysis was performed to compare the neurodevelopment of children according to frequency of yogurt consumption. For the covariates, items related to the socio-economic background and children's neurodevelopment were selected with reference to previous studies.

resultsConsumption of yogurt 1-4 times/week was associated with a reduced risk of developmental delay in all ASQ-3 categories(adjusted odds ratios, 0.71-0.87). However, the risk of developmental delay was not necessarily reduced with yogurt consumption ≥5 times/week (adjusted odds ratios, 0.84-0.96).

conclusionYogurt consumption habits at 1 year of age were associated with a lower risk of developmental delay at 3 years of age. However, the association was less apparent when yogurt was consumed more frequently. Possible mechanisms by which yogurt intake affects neurodevelopment include neurotransmitters produced by intestinal bacteria as well as the suppression of intestinal inflammation through improvements in the intestinal environment. Regular intake of yogurt in early childhood may have a positive association with neurodevelopment, but it is hoped that clearer links will be found in the future through intervention studies.