Influence of fiber, xylitol and fructose in enteral formulas on glucose and lipid metabolism in normal subjects.

To verify the benefit of nonglucose carbohydrates and fiber in enteral formula diets we studied the postprandial metabolism of eight healthy subjects after the intake of two helpings (25 g carbohydrates each) of five commonly used enteral formulas over 4 h. There were no significant differences in postprandial concentrations of blood glucose among the formulas. The area under the curve of postprandial insulin values, however, was significantly smaller after consumption of the fructose-containing formula (1948 +/- 285 microU min ml-1, P < 0.05) than after fiber-free (3222 +/- 678 microU min ml-1) or two fiber-containing products (2664 +/- 326 microU min ml-1, P < 0.05; and 3040 +/- 708 microU min ml-1, P < 0.05). The insulin area of the xylitol-containing formula (2307 +/- 364 microU min ml-1) was significantly smaller compared to the fiber-free product (P < 0.05). In addition, we found the postprandial increase in triglycerides to be significantly higher after the xylitol-containing formula (from 0.93 +/- 0.14 to 1.25 +/- 0.22 mmol/l) than after the fiber-free product (from 0.82 +/- 0.13 to 0.97 +/- 0.16 mmol/l, P < 0.05) or the two fiber-containing products (from 0.88 +/- 0.16 to 0.96 +/- 0.18 mmol/l, P < 0.05; and from 0.80 +/- 0.08 to 0.95 +/- 0.10 mmol/l, P < 0.05). We conclude that a patient with type II diabetes may benefit from replacing glucose and glucose-equivalent carbohydrates with fructose or xylitol.