Supplementary Material for: The nutritional quality of gluten-free vs. non-gluten-free pre-packaged foods and beverages sold in Hong Kong

Introduction: The consumption of gluten-free foods has continued to increase in recent years. Given their higher intake amongst individuals both with or without a medically diagnosed gluten allergy or sensitivity, it is important to understand how the nutritional quality of these foods compares against non-gluten-free foods. As such, we aimed to compare the nutritional quality of gluten-free and non-gluten-free pre-packaged foods sold in Hong Kong. Methods: Data from 18,292 pre-packaged food and beverage items in the 2019 FoodSwitch Hong Kong database were used. These products were categorized as (1) “declared gluten-free”; (2) “gluten-free by ingredient or naturally gluten-free” and (3) "non-gluten-free” according to information presented on the package. One way ANOVA was used to compare the differences in the Australian Health Star Rating (HSR), energy, protein, fibre, total fat, saturated fat, trans-fat, carbohydrates, sugars and sodium content between products in different gluten categories, overall and by major food category (e.g., bread and bakery products) and region of origin (e.g., America, Europe). Results: Products declared gluten-free (mean ± SD: 2.9 ± 1.3; n = 7%) had statistically significantly higher HSR than those gluten-free by ingredient or naturally gluten-free (2.7 ± 1.4; n = 51.9%) and non-gluten-free (2.2 ± 1.4; n = 41.2%) (all pairwise comparisons p < 0.001). Overall, non-gluten-free products have higher energy, protein, saturated fat, trans-fat, free sugar and sodium, and less fibre compared with products in the other two gluten categories. Similar differences were observed across major food groups and by region of origin. Conclusions: Non-gluten-free products sold in Hong Kong were generally less healthy than gluten-free products (regardless of presence of gluten-free declaration). Consumers should be better educated on how to identify gluten-free foods given many gluten-free foods do not declare this information on the label.

引言：近年来，无麸质食品的消费量持续攀升。无论是经医学诊断患有麸质过敏或麸质敏感性的人群，还是普通大众，其无麸质食品的摄入量均有所增加，因此明确此类食品与非无麸质食品的营养品质差异至关重要。为此，本研究旨在对比香港在售预包装无麸质食品与非无麸质食品的营养品质。方法：本研究采用2019年香港FoodSwitch数据库中18292项预包装食品与饮料的数据。根据包装标注信息，将这些产品划分为三类：(1) 标注为“无麸质”；(2) “原料不含麸质或天然无麸质”；(3) “非无麸质”。本研究采用单因素方差分析（One-way ANOVA），对比不同麸质类别产品在澳大利亚健康星级评分（Health Star Rating, HSR）、能量、蛋白质、膳食纤维、总脂肪、饱和脂肪、反式脂肪、碳水化合物、总糖以及钠含量方面的差异，分析维度涵盖整体样本、主要食品类别（如面包及烘焙制品）以及产地来源（如美洲、欧洲）。结果：研究结果显示，标注为“无麸质”的产品（均值±标准差：2.9±1.3；样本占比7%）的健康星级评分显著高于“原料不含麸质或天然无麸质”类产品（2.7±1.4；样本占比51.9%）与“非无麸质”类产品（2.2±1.4；样本占比41.2%），所有两两比较的p值均小于0.001。整体而言，与另外两类麸质产品相比，非无麸质产品的能量、蛋白质、饱和脂肪、反式脂肪、游离糖以及钠含量更高，而膳食纤维含量更低。这一差异在主要食品类别以及不同产地来源的产品中均一致存在。结论：本研究表明，香港在售的非无麸质食品整体健康性普遍低于无麸质食品（无论是否标注无麸质相关信息）。鉴于市场上诸多无麸质食品并未在标签上标注相关信息，消费者应接受更全面的相关教育，以掌握识别无麸质食品的方法。