The classification and measurement of dietary carbohydrates

Major advances in our understanding of the digestive physiology of dietary carbohydrates and their potential benefit to health require new and more informative techniques to replace the traditional ‘by difference’ measurement. The human diet contains a range of chemically distinct carbohydrates and research, as well as labelling for dietary carbohydrates including dietary fibre, should be based on the classification and measurement of chemically identified components. Such values do not become obsolete and can be used in different combinations for different purposes. We present a new scheme for carbohydrate classification, including a new class of short-chain carbohydrates (SC). The classification and measurement of nutritionally important types of starch includes its division into rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS). In addition, a new category of rapidly available glucose (RAG) is described, which is the amount of glucose from free sugar and starch that is rapidly available for absorption. Values for dietary fibre based on the measurement of plant cell-wall NSP aid the consumer in choosing the type of high-fibre diet recommended in the dietary guidelines and are, therefore, appropriate for food labelling. The AOAC Prosky procedure, in contrast, is not specific for plant cell-wall material but includes substances that are formed by food processing and by treatment of analytical samples. Such values are not suitable for food labelling because they do not aid the consumer in choosing the recommended diet.