Insulin-like growth factor I concentrations in infancy predict differential gains in body length and adiposity: the Cambridge Baby Growth Study

Abstract

Background: Formula milk-fed infants show faster rates of growth and weight gain than do breastfed infants, and they have higher concentrations of insulin-like growth factor I (IGF-I). Objective: Our objective was to determine the influence of IGF-I concentrations on gains in weight, length, body mass index (BMI), and adiposity in the first year of life. Design: IGF-I concentrations were measured in 953 capillary blood samples from 675 unselected infants at ages 3 and 12 mo. These infants were born between 2002 and 2008 in one center and were participating in a prospective longitudinal birth cohort. Weight, length, and 4 skinfold thicknesses as an indicator of adiposity were measured at ages 0, 3, and 12 mo. Analyses were adjusted for age and sex. Results: Infants who were formula milk-fed had higher IGF-I concentrations at 3 mo, and they showed greater gains in weight, length, BMI, and adiposity between age 3 and 12 mo. IGF-I concentrations at 3 mo were unrelated to subsequent overall weight gain (P = 0.5). However, higher IGF-I concentrations at age 3 mo predicted greater subsequent gains in body length (P , 0.001 and P = 0.007 in formula milk-fed and breastfed infants, respectively) and slower gains in BMI (P , 0.001 and P = 0.004, respectively) and adiposity (P = 0.03 and P = 0.003, respectively). Conclusions: Our findings support a key role for IGF-I in the partitioning of overall infant weight gain into statural growth compared with adiposity. In formula milk-fed infants, higher IGF-I concentrations may lead to faster gains in length; however, other mechanisms likely explain their faster gains in weight, BMI, and adiposity. Am J Clin Nutr 2009;90:156-61.

Velocidade de ganho de peso e práticas alimentares no primeiro ano de vida em lactentes de baixo nível socioeconômico

“…Savino et al 31 demonstrou que crianças que recebiam leites artificiais tinham níveis mais elevados de grelina e Fator de Crescimento Insulina Tipo 1 (IGF-1) e menores ní-veis de leptina aos quatro meses de vida, o que sugere que o leite humano poderia mediar o controle da saciedade nas crianças que o consomem, diminuindo o apetite em comparação às desmamadas. Outros autores 32,33 também relataram maiores ganhos de peso com alimentação artificial em comparação ao leite materno, mas alertaram para a hipótese de que a proteção do leite materno para o ganho de peso excessivo pode não ocorrer por seus próprios efeitos, mas pela não utilização de outros leites não humanos, que, com maiores teores de proteína, ativariam maior resposta do hormônio IGF-1 e secreção de insulina e diminuiriam a secreção do hormônio do crescimento, levando a um consequente maior aumento do peso. Essa justificativa aplica-se à população estudada, pois se sabe que grande proporção de crianças que param de receber leite materno passa a consumir leite de vaca e outros alimentos complementares 34 com elevada quantidade de proteína quando comparados ao leite materno.…”

Breast milk nutrient content and infancy growth

“…In contemporary Western settings, breast feeding has been associated with slower gains in infancy weight 4 and body fat 5, and although debated has also been linked to lower risk for obesity and associated metabolic disease risk across the life course 6. It is unclear whether the slower infancy weight gain in breast‐fed babies is a result of lower total calorie intake or related to the nutrient composition of human breast milk (HM).…”

Dietary proteins and IGF I levels in preterm infants: determinants of growth, body composition, and neurodevelopment

“…Thus, higher IGF I levels were associated with a subsequent lower BMI (28,29). This might imply that high IGF I levels protect against adiposity.…”