Insulin-like Growth Factor-I (IGF-I) and skinfold thickness in breast fed and formula fed infants in the first months of life.

IGF-I is an insulin-like peptide synthesized by liver and is a key control point in nutritional regulation for growing. It has been found in human milk, otherwise its presence in milk-formula has not been detected. Growth and body composition differences between breast (BF) and formula-fed (FF) infants are at the moment not completely understood. There is evidence that an excessive protein intake could result in increased IGF-I levels providing a different body composition and an early adiposity rebound. Aim: To evaluate the correlation between IGF-I, nutrition (BF vs FF), skinfold thickness in infants in the first months of life. Conclusions: Our data provide a testable hypothesis of body composition's hormonal regulation according to the type of feeding in the first months of life. The increased IGF-I levels and higher tricipital skinfold observed in FF infants might be primarily caused by an higher protein intake, and this could increase the risk of obesity later in life. These findings further support the beneficial effect of BF during the first months of life.