New estimates of fibre in the diet in Britain.

New estimates of fibre in the diet in Britain Intakes of dietary fibre or its components have been (inversely) related to the prevalence of several diseases of the intestinal tract, including cancer, and to ischaemic heart disease, obesity, and diabetes. Recent reports on diet and health have accepted that benefit is likely to accrue from an increased intake of dietary fibre, particularly cereal fibre. Only the most recent of these reports has attempted to quantify the amount needed: it recommends that the average intake in Britain should rise from 20 g to 30 g/person/day, with a rise to at least 25 g by 1990.1 The estimate of the current intake2 was based on household food consumption statistics recorded in 1976 by the Ministry of Agriculture, Fisheries , and Food's National Food Survey and used dietary fibre measurements from McCance and Widdowson's The Composition of Foods.' The component fractions of fibre were mainly those of Southgate et al.4 These analyses had been carried out between 1969 and 1976, however, and starch was removed by digestion with takadia-stase, which was likely to have been contaminated with enzymes also capable of digesting part of the cellulose and hemicelluloses. As consumption of brown and wholemeal bread, which contains more fibre, has also increased substantially in Britain since 1976, there is a clear need for new and accurate information on the amounts of dietary fibre in foods and of its constituent fractions. When the Ministry of Agriculture, Fisheries, and Food assumed sole responsibility for revising the British food compositioti tables 'he first foods to be analysed included 103 types of bread and other cereal 4products and 35 meat products which contain cereals. The method for measuring fibre was still based on the original fractionation technique of Southgate,4 but it had been improved in that a mixture of amyloglucosidase and cc-amylase was used to break down starch; this was followed by digestion with hot 5% sulphuric acid for one hour and then with 72% sulphuric acid overnight at 40C. Sugars and uronic acids in these hydrolysates were measured colorimetrically, and the final residue (lignin) was weighed. Dietary fibre was taken as the sum of the lignin, cellulose, and non-cellulosic polysaccharides weighed during this fractionation method. The most important consequences of the modifications of the fractionation technique were that more pentose and hexose non-cellulosic polysaccharides were found and a greater residue of lignin remained. For example, sliced …