LYON, FranceIncreased consumption of fermentable fiberscommon to most fruits and vegetablestriggers the production of glucose by the intestine, which may help prevent diabetes and obesity, according to a new study published in the journal Cell.

Most sweet fruit and many vegetablessuch as salsify, cabbage and beansare rich in fermentable fibers, which cannot be digested directly by the intestine. Instead, these fibers are fermented by intestinal bacteria into short-chain fatty acids, such as propionate and butyrate, which can then be assimilated by the body.

Although the protective effect of these fibers is well knownanimals fed a fiber-rich diet become less fat and are less likely to develop diabetes than animals fed a fiber-free dietresearchers have been uncertain of the relationship between the fibers and obesity- and diabetes-prevention.

French-Swedish researchers from CNRS, Inserm and the Université Claude Bernard Lyon studied the capacity of the intestine to produce glucose to determine whether the connection between fiber intake and obesity- and diabetes-prevention lies in the intestine's glucose production, brought on by fiber consumption.

Researchers subjected rats and mice to diets enriched with fermentable fibers, or with propionate or butyrate, which caused a strong induction of the expression of genes and enzymes responsible for the synthesis of glucose in the intestine. Mice fed a fat- and sugar-rich diet, but supplemented with fibers, became less fat than control mice and were also protected against the development of diabetes.

The researchers repeated the experiment with mice whose intestines ability to produce glucose had been suppressed by genetic engineering. No protective effect was observed; these mice became fat and developed diabetes like those fed a fiber-free diet.

Researchers concluded that consumption of fermentable fiberscommonly found in fruits in vegetablesincreases the production of glucose by the intestine, which in turn, may prevent obesity and diabetes.