Abstract
Understanding of what is now designated as dietary fibre has evolved through the ages. For centuries it was viewed merely as the tougher and perhaps rougher component of plant foods, and its recognised laxative properties were assumed to result from a presumed irritant action on the gut. As milling processes allowed some of the coarser elements to be removed and used for cattle fodder, the term bran was applied to this low quality fraction of milled wheat. Early in the 19th century, what remained of plant food, after sequential heating; first in diluted acid and then in alkali was described as “crude fibre”, which consisted merely of part of the cellulose and the lignin, but contained none of the components now designated non-cellulosic polysaccharide. Although this method was designed for veterinerary practice, it was for long and quite inappropriately applied to human nutrition.