EFFECTS OF DIETARY FIBER MIXTURES ON GLUCOSE AND LIPID-METABOLISM ANDON MINERAL ABSORPTION IN THE RAT

Four diets containing different mixtures of dietary fibre (DF) were te sted in the rat to verify the effects of fibre source and fibre level on plasma glucose, insulin and lipids and on apparent intestinal absor ption of minerals. Diets Puri5 and Puri 10 contained 5 and 10% of tota l DF from pectin and cellulose. Diets Bran 5 and Bran 10 supplied 5 an d 10% DF from oat bran and wheat bran. A fifth diet with 5% cellulose was used as a control. Ten rats were fed each diet for 4 weeks. On day s 3, 17 and 28, feces were collected and analyzed for Fe, Zn, Ca and M g. On day 29, blood samples were collected in portal vein and abdomina l aorta in fasted and fed rats from each group. All diets had similar effects on plasma insulin and triglycerides. Compared to Bran diets, P url diets induced higher portal glucose (p < 0.01) and lower plasma ch olesterol (p < 0.03) in fed rats. The apparent absorption of Fe, Zn an d Mg was higher (p < 0.05) in rats fed Purl diets than in those fed Br an diets. For Ca, the difference was significant only on day 3. In thi s study, only the apparent absorption of Fe was affected (p < 0.01) by fibre level (5 >10%). This indicates that in fibre mixtures, the sour ce rather than the amount of fibre generally affects absorptive and me tabolic parameters.