Systematic reviews were conducted as part of the U.S. Department of Agriculture and Department of Health and Human Services Pregnancy and Birth to 24 Months Project. The goal of this systematic review was to examine the following question: What is the relationship between timing of introduction of complementary foods and beverages (CFB) and growth, size, and body composition? Complementary feeding is the process that starts when human milk or infant formula is complemented by other foods and beverages, beginning during infancy and typically continuing to 24 months of age. CFB were defined as foods and/or beverages other than human milk or infant formula (liquids, semisolids, and solids) provided to an infant or young child to provide nutrients and energy.
Moderate evidence suggests that first introduction of any complementary food or beverage (CFB) between 4-5 months compared to approximately 6 months of age is not associated with weight status, body composition, body circumferences, weight, or length among generally healthy, full-term infants. Limited evidence suggests that introducing CFB before 4 months of age may be associated with higher odds of overweight/obesity. There is not enough evidence to determine the relationship between introduction of CFB at 7 months of age or older on growth, size, or body composition.
This systematic review was conducted by a team of staff from the Nutrition Evidence Library in collaboration with a Technical Expert Collaborative. Literature search was conducted using 4 databases (PubMed, Cochrane, Embase, and CINAHL) to identify articles that evaluated the intervention or exposure of timing of CFB introduction and the outcomes of developmental milestones. A manual search was conducted to identify articles that may not have been included in the electronic databases searched. Articles were screened by two analysts? independently for inclusion based on pre-determined criteria. Data extraction and risk of bias assessment were conducted for each included study, and both were checked for accuracy. The body of evidence was qualitatively synthesized to inform development of a conclusion statement(s), and the strength of evidence was graded using pre-established criteria evaluating the body of evidence on risk of bias, adequacy, consistency, impact, and generalizability.
This review includes 81 articles that examined the association between timing of introduction of CFB and growth, size, and/or body composition across the lifespan. Timing of CFB introduction is the age at which any or specific types of CFB were first consumed and was examined as early as 1 month and as late as 12 months of age. Timing of CFB introduction was not associated with growth, size, body composition, and/or weight status in the majority of included studies. A limited number of observational studies suggested that CFB introduction before 4 months of age was associated with higher odds of overweight/obesity. Given the normal variation in healthy child growth patterns, caution should be used when interpreting results between timing, types and/or amounts of CFB and outcomes for individuals based on findings at the population level.
