Cross-sectional associations of diet and insulin-like growth factor levels in 7- to 8-year-old children.

BACKGROUND: The insulin-like growth factors (IGF) are polypeptide hormones which are associated with several adult diseases including cancer and coronary heart disease. The dietary determinants of circulating levels of components of the IGF system are of interest, as these may mediate some of the effects of diet on later health. However, few studies have examined the relationship between diet and IGF levels in children.OBJECTIVE: To investigate associations between diet and IGF-I and IGFBP-3 levels in 7- to 8-year-old children.METHODS: This study used subjects participating in the Avon Longitudinal Study of Parents and Children. Diet was assessed using a 3-day unweighed food diary. Confounding variables considered were maternal education, housing tenure, birthweight, and body mass index.RESULTS: Complete information on dietary intakes, IGF levels, and all confounding variables were available for 521 children (287 boys). IGF-I was positively associated with intakes of protein, magnesium, zinc, calcium, potassium, and phosphorus, and IGFBP-3 was positively associated with energy. The IGF-I/IGFBP-3 ratio was positively associated with intakes of protein, zinc, and phosphorus. There was some evidence that the dietary determinants of the IGF system differed between the sexes. None of the foods examined were strongly associated with IGF levels, in particular, there was no association with red meat or vegetable intake.CONCLUSION: These data suggest that the IGF axis in children is affected by diet. This may provide a mechanism whereby childhood diet could have a long-term effect on risk of chronic disease.