CONTRIBUTION OF BARLEY FIBER TO THE METABOLIZABLE ENERGY OF HUMAN DIETS

The metabolizable energy (ME) of a low fiber diet and of a high fiber diet supplemented with 15 g dietary fiber (DF) from a barley fiber concentrate was determined in balance experiments in 12 young women. The ME of the diets was also calculated by energy assessment procedures. Total daily intake of DF was 22.5 g with the low fiber diet and 38.6 g with the high fiber diet. The addition of barley fiber decreased the digestibility of dietary energy (95.0 vs. 92.7 %) and NSP (83.2 vs. 65.4 %) significantly, whereas the digestibility of nitrogen and fat was not affected. The partial digestible energy value of the barley fiber was calculated to be 3 kJ (0.8 kcal)/g. This value is above the energy value calculated for whole grain fiber, but lower than that for fiber from mixed diets. The ME of the experimental diets could best be estimated by the equations of Southgate and of Livesey and by a modification of the British energy assessment procedure.