Objective: Milk protein may stimulate linear growth through insulin-like growth factor-1 (IGF-1). However, the effect of plant proteins on growth factors is largely unknown. This study assesses the effect of combinations of milk and rapeseed protein versus milk protein alone on growth factors in children.

Design: An exploratory 3-armed randomized, double-blind, controlled trial was conducted in 129 healthy 7–8 year-old Danish children. Children received 35 g milk and rapeseed protein (ratio 54:46 or 30:70) or 35 g milk protein per day for 4 weeks. The primary outcome was difference in IGF-1 changes between intervention groups after 4 weeks. Secondary outcomes included changes in IGF-1 after 1 week and changes in insulin-like growth factor binding protein-3 (IGFBP-3), IGF-1/IGFBP-3, insulin, height, weight and body composition after 1 and 4 weeks. Results were analysed by multiple linear mixed-effect models.

Results: There were no differences in changes of plasma IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3), IGF-1/IGFBP-3 ratio or insulin between groups after 1 or 4 weeks based on 89 complete cases (P > 0.10). IGF-1 increased by 13.7 (95% CI 9.7;17.7) ng/mL and 18.0 (14.0;22.0) ng/mL from baseline to week 1 and 4, respectively, a 16% increase during the intervention. Similarly, insulin increased by 31% (14; 50) and 33% (16; 53) from baseline to week 1 and 4. Fat-free mass index (FFMI) increments were higher with milk alone than rapeseed blends (P < 0.05), coinciding with a trend towards a lower height increment. Body mass index increased within all groups (P < 0.05), mainly due to an increase in FFMI (P < 0.01).

Conclusion: There were no differences in changes of growth factors between the combinations of milk and rapeseed protein and milk protein alone in healthy, well-nourished children with a habitual intake of milk. Within groups, growth factors increased considerably. Future studies are needed to investigate how intakes of plant and animal proteins affect childhood growth.

目的：牛奶蛋白可能通过胰岛素样生长因子-1（IGF-1）刺激线性生长。然而，植物蛋白对生长因子的影响在很大程度上是未知的。本研究评估了牛奶和油菜籽蛋白的组合与单独的牛奶蛋白对儿童生长因子的影响。

设计：在 129 名健康的 7-8 岁丹麦儿童中进行了一项探索性的 3 臂随机、双盲、对照试验。儿童每天接受 35 克牛奶和油菜籽蛋白（比例为 54:46 或 30:70）或 35 克牛奶蛋白，持续 4 周。主要结果是 4 周后干预组之间 IGF-1 变化的差异。次要结果包括 1 周后 IGF-1 的变化以及 1 周和 4 周后胰岛素样生长因子结合蛋白 3 (IGFBP-3)、IGF-1/IGFBP-3、胰岛素、身高、体重和身体成分的变化. 通过多个线性混合效应模型分析结果。

结果：基于 89 个完整的 89例（P  > 0.10）。从基线到第 1 周和第 4 周，IGF-1 分别增加了 13.7 (95% CI 9.7;17.7) ng/mL 和 18.0 (14.0;22.0) ng/mL，干预期间增加了 16%。同样，从基线到第 1 周和第 4 周，胰岛素分别增加了 31% (14; 50) 和 33% (16; 53)。单用牛奶的无脂肪质量指数 (FFMI) 增量高于混合油菜籽 ( P  < 0.05) ，与降低高度增量的趋势相吻合。各组体重指数均增加（P < 0.05），主要是由于FFMI增加（P  < 0.01）。

结论：牛奶和菜籽蛋白的组合和单独的牛奶蛋白在有习惯性摄入牛奶的健康、营养良好的儿童中生长因子的变化没有差异。在组内，生长因子显着增加。未来的研究需要调查植物和动物蛋白的摄入量如何影响儿童成长。