['Prevention of Type 1 diabetes mellitus (T1DM), a major childhood chronic disease with rapidly increasing incidence, is an urgent topic of research. We investigated whether 5% oligofructose (OF) as compared to 5% cellulose had a protective effect against diet-induced T1DM in the diabetes-prone BioBreeding (BB) rat model.', 'Groups of BB rats were fed the experimental diets from weaning. The diets were a cereal-based rodent diet (diabetogenic, positive control) and semi-synthetic rodent diets containing hydrolysed casein (non-diabetogenic, negative control), soy or whey as the sole protein source and 5% cellulose as fibre source. In additional groups fed soy and whey protein, the fibre source was 5% OF. T1DM incidence up to the age of 160 days was recorded applying biochemical and morphological criteria. Physiological effects of fibre were assessed through the analysis of biochemical parameters in plasma and of the protein/DNA ratio in intestinal mucosa.', 'T1DM incidence was diet-dependent. Cereal-, soy- and whey-based diets were significantly more diabetogenic than the hydrolysed casein-based diet. Five per cent OF did not affect the incidence of T1DM induced by either soy or whey proteins as compared to cellulose, nor induce any of the biological effects attributed to a fermentable fibre.'] Does oligofructose affect the development of type 1 diabetes mellitus induced by dietary proteins in the diabetes-prone BB rat model?