ABSTRACT
AIM: To determine the concentration of insulin-like growth factor-I (IGF-I) in exclusively breast-fed (BF) and formula-fed (FF) infants in the first 5 months of life and to study the relationship between the IGF-I level and Z score for weight, body mass index (BMI) and tricipital skin-fold thickness. METHODS: We performed a cross-sectional study in order to evaluate serum IGF-I in 97 age-matched healthy term infants: 50 FF and 47 BF. RESULTS: FF infants showed higher values of IGF-I (38.9 +/- 12 ng/ml) when compared to BF infants (26.7 +/- 11.6 ng/ml; p < 0.05). A positive correlation was found between IGF-I values and Z score for weight (p < 0.001), BMI (p = 0.014), tricipital skin-fold thickness (p = 0.043) and age (p = 0.02). CONCLUSION: These results show that the IGF-I serum concentration is higher in FF infants. The observed association between IGF-I and Z score for weight, BMI, tricipital skin-fold thickness confirms the effect of different infant feeding on body size.
Subject(s)
Body Mass Index , Body Weight/physiology , Breast Feeding/statistics & numerical data , Infant Formula/statistics & numerical data , Insulin-Like Growth Factor I/metabolism , Skinfold Thickness , Analysis of Variance , Arm/physiology , Cross-Sectional Studies , Female , Humans , Infant , Infant Formula/administration & dosage , Infant, Newborn , Male , Reference ValuesABSTRACT
BACKGROUND: Leptin is a hormone present in breast milk, which regulates food intake and energy metabolism. AIM: To investigate whether leptin levels are different in breast-fed (BF) or formula-fed (FF) infants in the first months of life. METHODS: We evaluated serum leptin by radio-immunoassay and anthropometric parameters in 51 infants at the average age of 62.8+/-30 days, 25 exclusively BF and 26 exclusively FF. RESULTS: Leptin serum values were higher in BF (7.1+/-10.4 ng/ml) than in FF (3.7+/-3.87 ng/ml) infants (p <0.05). Leptin values were higher in females (6.9+/-9.87 ng/ml) than in males (3.5+/-3.88 ng/ml) (p <0.05). No differences were found in anthropometric measurements and body mass index. CONCLUSION: The kind of feeding might be a factor affecting serum leptin concentration in term infants. The long-term consequences of this difference between BF and FF infants and leptin's role in promoting obesity later in life are unknown.
