Ghrelin, leptin and IGF-I levels in breast-fed and formula-fed infants in the first years of life

AIM: To establish ghrelin, leptin and IGF-I serum levels in breastfed (BF) and formula-fed (FF) infants during the first period of life. METHODS: A cross-sectional study was conducted on fasting blood venous samples obtained from exclusively BF (n=106) and FF (n=100) infants to measure total ghrelin (RIA test), leptin (RIA test) and IGF-I (chemiluminescence). Anthropometrical measurements of weight, length and cranial circumference were performed. RESULTS: During the first 4 mo of life, FF infants compared to BF ones showed higher ghrelin levels (2654.86 vs 2132.96 pg/ml; p<0.032), higher IGF-I levels (3.73 vs 3.15 ng/ml; p=0.00) and lower leptin levels (0.68 vs 1.16 ng/ml; p<0.04). Leptin values were higher in females than in males (0.80 vs 0.47 ng/ml; p<0.03), while no gender-related difference was found for ghrelin and IGF-I. No differences were found in anthropometrical measurements comparing the two groups of infants. A multiple regression analysis showed an inverse correlation between ghrelin and leptin values (p<0.04) and between IGF-I and leptin levels (p=0.00). CONCLUSION: Our finding suggests that breastfeeding influences hormones such as ghrelin, leptin and IGF-I in infancy, mainly during the first 4 mo of life. Further evidence is needed to confirm and clarify the role of a protective link from mother to infants as seen in our observations.