The research, published in Childhood Obesity, analysed data from more than 1,100 infants after previous epidemiological evidence suggested that the timing of introduction of solid foods may be associated with subsequent risk of obesity, and the association may vary by whether an infant is breastfed or formula-fed.
“Our aim, using data from a cohort of US children followed longitudinally throughout the first year of life, and contacted again at 6 years, was to assess how early introduction of solid foods (before 4 months) was associated with obesity at 6 years of age, and test for an interaction with breastfeeding status, controlling for multiple potential infant, child, and maternal confounders,” explained the research team – led by Chloe Barrera at the US Centers for Disease Control and Prevention.
In contrast with previous studies, which have suggested that an early move to solid foods may set baby on path to obesity and that ‘overeating’ infant formula linked to higher risk of obesity, Barrera and her colleagues did not find a significant association between timing of introduction of solid foods and child obesity at 6 years of age, the team revealed.
“Given the inconsistency in findings with other studies, further studies in larger populations may be needed,” they said.
Childhood Obesity editor-in-chief, Tom Baranowski, PhD, of Baylor College of Medicine, commented that future research will need to assess adiposity at multiple points before 6 years and possible metabolic influences that could result from early introduction of solids on later child obesity.
"Given the conflicting findings from previous research about whether the early introduction of solid foods increased the chances of a child becoming obese, this important large-sample long-term study from the CDC raises this key question anew,” said Baranowski.
‘No effect’, says CDC data
Barrera and her colleagues analysed data on 1181 infants who participated in the Infant Feeding Practices Study II (IFPS II) and the Year 6 Follow Up (Y6FU) study, to determine obesity, and also explored the potential impact of breast versus formula feeding.
The team compared the chances of child obesity at six years of age depending on whether infants first began eating solid foods earlier than four months, between four to six months, or at or later than six months of age. They found that more than one in 10 (12%) of the six-year-olds included in the study were obese, but the time of introduction of solids had no effect after statistical adjustments.
“The odds of obesity was higher among infants introduced to solids less than four months compared to those introduced at four to less than six months in unadjusted analysis; however, this relationship was no longer significant after adjustment for covariates.”
The CDC researchers then used multivariable logistic regression to assess the association between timing of the introduction of solids and obesity at six years and test whether this association was modified by breastfeeding duration (breastfed for four months vs. not).
“We found no interaction between breastfeeding duration and early solid food introduction and subsequent obesity,” they said.
Despite the findings that time of solid food introduction appears to have no impact on obesity risk, the team concluded that optimal infant feeding practices, including exclusive breastfeeding for approximately the first six months of life, timely introduction of complementary foods, and continued breastfeeding for at least the first year, “should be promoted and supported for all infants because of the numerous health benefits for infants and mothers.”
Source: Childhood Obesity
Published online ahead of print, doi: 10.1089/chi.2016.0021
“Age at Introduction to Solid Foods and Child Obesity at 6 Years”
Authors: Chloe M Barrera, et al