Metabolism of L-Sorbose in the Rat and the Effect of the Intestinal Microflora on its Utilization Both in the Rat and in the Human

L-[U-¹⁴C]-sorbose was administered orally as single doses to 5 normal rats. The recovery of radioactivity was 5.3% in the urine, 46% in the faeces exclusively as L-sorbose and 16% as carbon dioxide. Caloric utilization was approximately 25%. A second group of 3 rats that had previously received L-sorbose in their diet showed ¹⁴C recoveries of 8.9% in the urine, 6.6% in the faeces and 59% as carbon dioxide. The time course of expired carbon dioxide suggests that a portion of L-sorbose was rapidly absorbed and partially metabolized while the principal pathway involved fermentation by the intestinal microflora to volatile fatty acids which were subsequently absorbed and metabolized. The total caloric utilization of L-sorbose was estimated to be 70%. It was observed that a human intestinal microflora also required an adaptation period in order to ferment this sugar. The efficiency of the fermentation was estimated to be 70%.