Macronutrient composition of early childhood diet is associated with growth and adiposity

Abstract

BackgroundPrevious studies suggest that high protein intake in infancy leads to a higher body mass index. However, it is not clear whether lean or fat mass are affected and what the role is of the other macronutrients in the diet. We examined associations of macronutrient composition of the diet in early childhood with growth and detailed measures of body composition up to the age of 9 years.MethodsThis study was performed among 3,564 children participating in a population‐based cohort study in the Netherlands. Dietary intake was assessed with food‐frequency questionnaires at age 1 year. We calculated intakes of total protein and protein from different sources; of total carbohydrates, fiber, polysaccharides, monosaccharides and disaccharides; and of total, saturated, monounsaturated and polyunsaturated fat. Height and weight were repeatedly measured between the ages of 1 and 9 years. Fat and fat‐free mass were measured at 6 and 9 years using dual X‐ray absorptiometry. We calculated age‐ and sex‐specific SD scores for height, weight, body mass index (BMI), fat‐mass index (FMI), and fat‐free mass index (FFMI). Macronutrient intakes were expressed in energy percentages and entered in multivariable linear mixed models in which we examined different macronutrient replacement effects. Models were adjusted for maternal age, education, BMI, and smoking and for child's sex, age, ethnicity, birth weight, having received breastfeeding, diet quality, television watching, and playing sports.ResultsMean (±SD) macronutrient intakes were 12.9 (±2.4) E% from protein, 28.6 (±5.6) E% from fat, and 58.4 (±5.9) E% from carbohydrates. Results from multivariable models showed that higher intake of total and animal protein (both dairy and non‐dairy) was associated with a higher height, weight and BMI up to the age of 9 years, irrespective of whether it was replacing carbohydrates or fats in the diet. Further analyses showed that the positive association with BMI was completely explained by a higher FMI, and not by FFMI. In multivariable models, no significant associations were observed for any of the other macronutrients.ConclusionsOur results suggest that high protein intake, particularly animal protein, in early childhood is associated with a higher body fat mass, but not fat‐free mass. Future studies are needed to examine the optimal range of protein intake and macronutrient composition of the diet for infants and young children.