Early Life Protein Intake: Food Sources, Correlates, and Tracking across the First 5 Years of Life

Background High consumption of protein has been associated with accelerated growth and adiposity in early childhood. Objective To describe intake, food sources, correlates, and tracking of protein in young children. Design Secondary analysis of Melbourne Infant Feeding Activity and Nutrition Trial (InFANT). Dietary data were collected using three 24-hour dietary recalls at ages 9 and 18 months as well as 3.5 and 5 years. Participants/setting First-time mothers and their child (n=542) participated in an 18 month intervention to prevent childhood obesity and the cohort was followed-up with no intervention when children were aged 3.5 and 5 years. Main outcome measures Protein intake, food sources, correlates, and tracking of protein. Statistical analyses performed Child and maternal correlates of protein intake were identified using linear regression and tracking of protein intake was examined using Pearson correlations of residualized protein scores between time points. Results Mean protein (grams per day) intake was 29.7 +/- 11.0, 46.3 +/- 11.5, 54.2 +/- 13.8, and 60.0 +/- 14.8 at 9 and 18 months and 3.5 and 5 years, respectively. Protein intakes at all ages were two to three times greater than age-appropriate Australian recommendations. The primary source of protein at 9 months was breast/formula milk. At later ages, the principal sources were milk/milk products, breads/cereals, and meat/meat products. Earlier breastfeeding cessation, earlier introduction of solids, high dairy milk consumption (>= 500 mL), and high maternal education were significant predictors of high protein intake at various times (P<0.05). Slight tracking was found for protein intakes at 9 months, 18 months, and 5 years (r=0.16 to 0.21; P<0.01). Conclusions This study provides unique insights into food sources and correlates of young children's high protein intakes, and confirms that early protein intakes track slightly up to age 5 years. These finding have potential to inform nutrition interventions and strategies to address high protein intakes and protein-related obesity risk.