Several observational studies among western children and adolescents suggest that protein intake is associated with body composition. However, this issue in Chinese children remains to be determined. Our aim was to examine whether protein intake is associated with body composition among children and adolescents in South China.
1250 participants (49% boys) aged 6-16 years were cross-sectionally recruited. Daily intakes of total/animal/vegetable protein were obtained by 3-d 24h dietary recalls. Height, weight, waist circumference and skinfold thickness were measured to calculate the indices of body composition [body mass index SD score (BMI SDS), waist-to-height ratio (WHtR), percentage of body fatness (BF%), fat mass index (FMI) and fat free mass index (FFMI)]. The association between tertiles of total/animal/vegetable protein intake (T1-T3) and the BMI SDS, WHtR, BF%, FMI and FFMI was investigated using multiple linear regression analysis for girls and boys, respectively.
In girls, a higher vegetable protein intake was related to a higher BMI SDS [mean (95% CI), T1: 0.09 (-0.16, 0.35), T2: 0.12 (-0.14, 0.38), T3: 0.35 (0.10, 0.61); P for trend = 0.001] and FFMI [mean (95% CI), T1: 14.33 (14.01, 14.65), T2: 14.44 (14.12, 14.77), T3: 14.60 (14.28, 14.92); P for trend = 0.01] adjusted for birth weight, maternal education level and maternal BMI. WHtR was lowest in girls with the moderate vegetable protein intake (P for trend = 0.04). There was no association between total/animal protein intake and body composition in girls. In boys, total/animal/vegetable protein intake was not associated with body composition.
Our results show that a higher vegetable protein intake might be related to a higher BMI SDS in girls from South China, which is primarily contributed to fat free mass.