Danone Nutricia Early Life Nutrition, Matrix Building #05-01b, 30 Biopolis Street, Singapore 138667.
Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, Netherlands.
Biomed Res Int. 2019 Jan 14;2019:3687416. doi: 10.1155/2019/3687416. eCollection 2019.
Salivary alpha-amylase (sAA) and salivary immunoglobulin A (sIgA) have been proposed as biomarkers for research on the mucosal immune system and on stress. Expression of both sAA and sIgA has been described to follow opposing diurnal patterns. This knowledge is crucial for the interpretation of studies using these biomarkers.
It was hypothesized that sAA and sIgA display diurnal patterns in children and that this is independent of food intake or demographic factors.
Whole saliva was collected from 78 healthy children (15-39 months old) in the morning and evening for two random nonconsecutive days. The samples have been analysed for sAA and sIgA. The total daily energy, fat, saturated fat, protein, carbohydrate and fibre, mineral, and vitamin consumption were analysed based on the two-day weighed food records collected by the parents.
It was demonstrated that most young children followed the diurnal pattern when sAA increased and sIgA decreased from morning to evening. No correlation was observed between the intake of any of the nutrients and morning or evening values for both salivary proteins. The morning and evening values of sAA and sIgA did not correlate with age, sex, Asian ethnicity, and BMI of the children.
Diurnal patterns of sAA and sIgA exist in healthy young children and are not affected by their nutrient intake, sex, Asian ethnicity, and BMI. Scientists including sIgA and sAA in their research must consider the diurnal pattern that these markers exhibit and design the study accordingly.
唾液α-淀粉酶（sAA）和唾液免疫球蛋白 A（sIgA）已被提议作为黏膜免疫系统和应激研究的生物标志物。sAA 和 sIgA 的表达均呈现出相反的昼夜模式。这一知识对于使用这些生物标志物的研究的解释至关重要。
假设 sAA 和 sIgA 在儿童中呈现昼夜模式，并且这种模式独立于食物摄入或人口统计学因素。
在两天的随机非连续时间内，早上和晚上从 78 名健康儿童（15-39 个月大）中采集全唾液样本。对样本进行 sAA 和 sIgA 分析。根据父母收集的两天称重食物记录，分析总日能量、脂肪、饱和脂肪、蛋白质、碳水化合物和纤维、矿物质和维生素的摄入。
结果表明，大多数幼儿的 sAA 增加，sIgA 从早上到晚上减少，呈现昼夜模式。在两种唾液蛋白的早晨和晚上值之间，没有观察到任何营养素摄入与这两种蛋白之间的相关性。sAA 和 sIgA 的早晨和晚上值与儿童的年龄、性别、亚洲种族和 BMI 均不相关。
健康的幼儿中存在 sAA 和 sIgA 的昼夜模式，不受其营养摄入、性别、亚洲种族和 BMI 的影响。包括 sIgA 和 sAA 在内的科学家在他们的研究中必须考虑这些标志物表现出的昼夜模式，并相应地设计研究。
