Dietary fibre, what it is and how it is measured

Carbohydrates are the major component of the human diet and are an important source of energy. The World Health Organization recommends that 50-70% of ingested carbohydrates should be in the form of polysaccharides such as starch. A small proportion of dietary carbohydrate is in the form of non-starch polysaccharides (NSP) (Dietary Fibre). Dietary Fibre is a medically important component of the diet since epidemiological evidence links it with the etiology of various diseases. Scientists have engaged in trying to understand the mechanism by which dietary fibre prevents disease. This article highlights the lack of consensus on its chemical definition and the advantages and disadvantages of the two main methods used to measure it. These are the enzymic gravimetric method (AOAC) that measure fibre as the weight of residual matter following enzymic treatment of the food; and the enzymic chemical method that identifies and measures fibre from its chemical components. The latter method, proposed by Englyst and Cummings measures dietary fibre as NSP and gives detailed information about its components. This is important for interpreting epidemiological and physiological studies. The precise and confident measure of the different components of carbohydrates is important in Latin America. It will allow a coherent, scientific and rational approach to the role of carbohydrates in health.