Chronic oat bran intake alters postprandial lipemia and lipoproteins in healthy adults.

This study evaluates the possible interaction between chronic oat bran intake and the postmeal metabolic response. Six normolipidemic men consumed three different diets for 14 d, at the end of which they consumed a test meal. The diets were C (control), basal low-fiber diet (15.6 g fiber/d) and a low-fiber (2.8 g fiber) test meal; OB (oat bran), basal low-fiber diet and a 40-g oat bran-enriched test meal (12.8 g fiber); and OB-A (oat bran-adaptation), 14-d oat bran (40 g/d) supplemented diet (23.8 g fiber/d) and an oat bran test meal (12.8 g fiber). The diets were fed in a random order. Fasting and postmeal blood samples were obtained for 7 h and lipoproteins were isolated. Adding oat bran to the test meals markedly reduced the postmeal insulin rise (P < 0.05). Compared with the low-fiber control diet, the effects elicited postprandially by adding oat bran to a single meal were enhanced after 14 d of oat bran feeding, ie, increased plasma triglycerides, phospholipids, and free cholesterol; decreased plasma esterified cholesterol; increased chylomicron and small-sized triglyceride-rich lipoprotein triglycerides; increased LDL and HDL free cholesterol; and decreased HDL esterified cholesterol. Thus, chronic oat bran feeding alters the postmeal response in human subjects.

Effects of pea and soybean fibre on postprandial lipaemia and lipoproteins in healthy adults.

To evaluate some possible mechanisms whereby total dietary fibre (TDF) may affect lipid metabolism in humans, six normolipidaemic males ingested on separate days a low-fibre test meal (2.8 g TDF) containing 70 g fat and 756 mg cholesterol, enriched with 10 g TDF in the form of either pea fibre or soybean fibre. Fasting and post-meal blood samples were obtained for 7 h and chylomicrons (CM) were isolated. Lipoproteins (VLDL+CM remnants, LDL, HDL) were isolated from the baseline samples and the samples of the 2-3 h triglyceride peaks. As compared to the postprandial response given by the control low-fibre test meal, adding fibre induced no change in serum glucose, insulin or Apo A1 and Apo B variations. The serum triglyceride response was not altered by adding fibres but the 2-3 h chylomicron triglyceride rise was increased (P < or = 0.05) by soybean fibre. VLDL+CM remnants, LDL and HDL triglyceride variations were unchanged with fibres. Cholesterolaemia decreased postprandially for 6 h, and was further lowered in the presence of pea fibre. This resulted from a marked decrease in serum esterified cholesterol. The chylomicron cholesterol and phospholipid rise was lowered in the presence of either fibre. The postprandial changes in the free cholesterol concentrations of the various lipoprotein classes were not altered by fibre whereas changes from baseline in esterified cholesterol concentrations were reduced by soybean fibre in LDL and amplified by soybean and pea fibres in HDL. The results obtained show that dietary fibre present in legumes may alter postprandial lipaemia and lipoproteins in humans to a variable extent. These effects could be related to some long-term metabolic effects.