What is the question?

• The question is: What is the relationship between the timing of introduction of complementary foods and beverages and developmental milestones?

What is the answer to the question?

• There is insufficient evidence to draw a conclusion about the relationship between the timing of introduction of complementary foods and beverages and developmental milestones. 

Why was this question asked? 

• This important public health question was identified and prioritized as part of the U.S. Department of Agriculture and Department of Health and Human Services Pregnancy and Birth to 24 Months Project.

How was this question answered? 

• A team of Nutrition Evidence Systematic Review staff conducted a systematic review in collaboration with a group of experts called a Technical Expert Collaborative

What is the population of interest? 

• Generally healthy infants and toddlers who were fed complementary foods and beverages from ages 0-24 months and had developmental milestones examined through 18 years of age

What evidence was found? 

• This review includes three studies published since 1980, including one randomized controlled trial and two observational studies.
• These studies compared timing of introduction of complementary foods and beverages (CFB) and developmental milestones during childhood through 18 years of age.
• Complementary foods and beverages 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.
• Different types of developmental milestone outcomes were measured between birth to 4 years of age, including:
  • communication development such as expressive language
  • cognitive development such as math skills
  • motor development such as age of crawling/walking
• There are limitations in the evidence as follows: wide variation in study design, especially the type and age of outcome assessment, as well as the potential for reverse causality

How up-to-date is this systematic review? 

This review includes literature from 01/1980 to 07/2016.

Background

• 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 developmental milestones? 
• 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. 
• 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. 

Conclusion Statement

• There is insufficient evidence to draw a conclusion about the relationship between the timing of introduction of complementary foods and beverages and developmental milestones. 

Grade

• Grade Not Assignable

Methods 

• This systematic review was conducted by a team of staff from the Nutrition Evidence Systematic Review in collaboration with a Technical Expert Collaborative. 
• A 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 authors 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 internal validity/risk of bias, adequacy, consistency, impact, and generalizability.

Summary of Findings 

• Three articles (one RCT; two observational studies) met criteria for inclusion that examined timing of introduction of CFB and developmental milestones
  • The RCT found no associations between timing of CFB and receptive or expressive language or fine- or gross-motor milestones at 30-35 months
  • One observational study reported that earlier CFB introduction at 4 months relative to at/after 6 months was associated with earlier gross-motor milestone achievement (e.g., crawling, cruising, and walking) via maternal report by 18 months of age
  • The other observational study found no associations between timing of CFB introduction and reading or math skills at 4 years of age.
  • The relationship between timing of introduction of CFB and developmental milestones may be influenced by a number of related factors, such as birth weight, current weight, type of early feeding (breast, formula, or mixed feedings), types and/or amount of human milk and CFB consumed, and the interval between exposure and outcome assessment

The ability to draw conclusions was restricted by an inadequate amount of or limited evidence with the potential for reverse causality, and wide variation in study design, type and age of outcome assessment, exposure assessment, and reported results