Englyst K N, Liu S, Englyst H N
Englyst Carbohydrates, University of Southampton Science Park, Southampton, UK.
Eur J Clin Nutr. 2007 Dec;61 Suppl 1:S19-39. doi: 10.1038/sj.ejcn.1602937.
Dietary carbohydrate characterization should reflect relevant nutritional and functional attributes, and be measured as chemically identified components. A nutritional classification based on these principles is presented, with a main grouping into 'available carbohydrates', which are digested and absorbed in the small intestine providing carbohydrates for metabolism, and 'resistant carbohydrates', which resist digestion in the small intestine or are poorly absorbed/metabolized. For the available carbohydrates, the chemical division into the starch and total sugars categories does not adequately reflect the physiological or nutritional attributes of foods. Characterizing carbohydrate release from starchy foods provides insight into some of the inherent mechanisms responsible for the varied metabolic effects. Also, a pragmatic approach to product signposting consistent with guidelines to limit free (or added) sugars is proposed. The most prominent of the resistant carbohydrates are the non-starch polysaccharides (NSP) from plant cell walls, which are characteristic of the largely unrefined plant foods that provide the evidence base for the definition and measurement of dietary fibre as 'intrinsic plant cell-wall polysaccharides' as proposed in conjunction with this paper and endorsed by the scientific update. Indigestibility in the small intestine was not considered to be an adequate basis for the definition of dietary fibre, as there is insufficient evidence to establish public health policy by this approach and concerns have been raised about potential detrimental effects of high intakes of rapidly fermentable resistant carbohydrates. Functional ingredients such as resistant starch and resistant oligosaccharides should therefore be researched and managed separately from dietary fibre, using specific health or function claims where appropriate. This structured approach to the characterization of nutritionally relevant features of dietary carbohydrates provides the basis for establishing population reference intakes, nutrition claims and food labelling that will assist the consumer with properly informed dietary choices.
膳食碳水化合物的特性应反映相关的营养和功能属性，并以化学鉴定的成分来衡量。本文提出了一种基于这些原则的营养分类方法，主要分为“可利用碳水化合物”和“抗性碳水化合物”。可利用碳水化合物在小肠中被消化和吸收，为新陈代谢提供碳水化合物；抗性碳水化合物则在小肠中抵抗消化或吸收/代谢不良。对于可利用碳水化合物，按淀粉和总糖类别进行化学划分并不能充分反映食物的生理或营养属性。描述淀粉类食物中碳水化合物的释放情况有助于深入了解一些导致不同代谢效应的内在机制。此外，还提出了一种与限制游离（或添加）糖的指南相一致的产品标识实用方法。最主要的抗性碳水化合物是植物细胞壁中的非淀粉多糖（NSP），它们是大部分未精制植物性食物的特征，这些食物为膳食纤维的定义和测量提供了证据基础，正如本文所提议并经科学更新认可的，膳食纤维定义为“内在植物细胞壁多糖”。小肠中的不可消化性不被认为是膳食纤维定义的充分依据，因为通过这种方法建立公共卫生政策的证据不足，而且人们对高摄入量的快速发酵抗性碳水化合物的潜在有害影响也表示担忧。因此，抗性淀粉和抗性低聚糖等功能性成分应与膳食纤维分开研究和管理，并在适当情况下使用特定的健康或功能声明。这种对膳食碳水化合物营养相关特征进行表征的结构化方法为确定人群参考摄入量、营养声明和食品标签提供了基础，这将有助于消费者做出明智的饮食选择。
