266 Effect of dietary protein intake on body mass index among primary school children

Abstract

<h3></h3> Recent studies have suggested that excessive dietary protein intake, especially animal-source protein, in infancy could affect health outcomes (e.g., obesity) in childhood. However, the effect of dietary protein intake in school-age children on growth and development is still unclear. The aim of this study was to assess dietary protein intake and its association with body mass index (BMI) in primary school children in Croatia. Anthropometric measurements of children (n=156; 50% boys) aged 8.3 ± 0.5 years from primary schools in Zagreb City were performed according to standard protocols. Sex- and age-standardized BMI z-scores were obtained using AnthroPlus software. A dietary record for 3 non-consecutive days was used to assess total protein intake and protein source. Adequacy of total protein intake (g/kg BW) was estimated by comparing with population reference intake of European Food Safety Authority (PRI EFSA). Of all school-age children involved in this study, 65% of them had adequate BMI, 22% were overweight or obese and 13% were underweight according to sex-standardized WHO BMI-for-age z-scores. Almost all (99.4%) children exceeded the PRI EFSA recommendation for protein intake. Average daily total protein intake was 2.3 ± 0.1 g/kg BW (68.4 ± 1.4 g/day), which is about 249 ± 72% of PRI EFSA recommendation. Children’s daily animal protein intake (1.5 ± 0.04 g/kg BW) was twice as much as plant protein (0.8 ± 0.02 g/kg BW), which was evident from the animal-plant protein ratio (2.1 ± 0.1). In line with logistic regression, adjusted for energy intake and gender, BMI was negatively associated with total protein intake, as well as with animal protein intake. Accordingly, children who had higher total protein intake (β=-5.087, OR 0.006, 95% Cl 0.001-0.04, p&lt;0.001) and animal protein (β=-3.298, OR 0.037, 95% Cl 0.008-0.167, p&lt;0.001) were less likely to be overweight and obese. No association was observed between BMI and plant protein intake. Intrinsically, results suggest that higher total and animal protein intake is associated with lower BMI in school-age children. However, additional studies with different designs would be required to determine the relationship between protein intake (total, animal and plant) and BMI or body composition in school-age children with respect to other lifestyle and environmental factors.