ABSTRACT
Metabolic factors acting during limited and sensitive time periods of pre- and postnatal development can induce lasting effects on health and disease risk in later life up to old age, including later obesity risk, which is referred to as early metabolic programming of long-term health. Three meta-analyses of observational studies found that obesity risk at school age was reduced with early breastfeeding compared to formula feeding. We assumed that breastfeeding protects against later obesity by reducing the occurrence of high weight gain in infancy and that one causative factor is the lower protein content of human milk compared to usual infant formulas (the "early protein hypothesis"). We are testing this hypothesis in the European Childhood Obesity Project, a double-blind, randomized clinical trial enrolling 1,678 infants in five countries (Belgium, Germany, Italy, Poland, Spain). We have randomized healthy infants born at term to receive for the first year infant formula and follow-on formula with higher or lower protein contents, respectively. The follow-up data obtained at age 2 years indicates that feeding formula with reduced protein content normalizes early growth relative to a breastfed reference group and the current WHO growth standard, which may furnish a significant long-term protection against later obesity. We conclude that infant feeding practice has a high potential for long-term health effects. The results obtained should stimulate the review of recommendations and policies for infant formula composition.
