Effect of refined cellulose on apparent energy, fat and nitrogen digestibilities.

Seven young women consumed a low cellulose diet for about 1 month and then the same diet for an additional month except that 16 g/day Solka Floc was added to the diet. Apparent digestibilities of energy, fat and nitrogen were measured for each subject during each diet. Digestibilities of fat and nitrogen were not affected by refined cellulose ingestion. Digestibility of nitrogen was 93.2% without and 92.9% with the Solka Floc, while fat digestibility was 96.3% during the control diet and 95.4% during the high cellulose diet. Mean digestibility of gross energy decreased significantly when cellulose was added to the diet, from 95.4% to 92.0% (P < 0.01). Undigested fecal fiber was the major source of the increased fecal energy. When fecal fiber energy was subtracted from total fecal energy and apparent energy digestibility recalculated, there was no difference in apparent energy digestibility during the 2 diets, 96.1% without and 95.6% with the Solka Floc supplement. Thus, ingestion of 16 g/day Solka Floc had no detrimental effect on the utilization of nitrogen and fat and increases in fecal energy could be explained by undigested refined cellulose.