A diet rich in oat bran improves blood lipids and hemostatic factors, and reduces apparent energy digestibility in young healthy volunteers

Abstract

Oat bran shows cholesterol-lowering properties, but its effects on other cardiovascular risk markers are less frequently investigated. This study examined the effects of oat bran on blood lipids, hemostatic factors and energy utilization. A double-blind, randomized crossover study in 24 adults (age 25.2±2.7 years; body mass index: 24.9±2.9 kg/m2), who completed two 2-week dietary intervention periods: low-fiber diet (control) or an oat bran (control +102 g oat bran/day) diet. Fasting blood samples were drawn before and after each period, and 3-day fecal samples were collected during the last week of each period. Total cholesterol decreased by 14% during the oat bran period compared with 4% during the control period (P<0.001). Non-high-density lipoprotein (HDL) cholesterol decreased by 16% in the oat bran period compared with 3% in the control period (P<0.01), as did total triacylglycerol (21 vs 10%, P<0.05) and very-low-density lipoprotein triacylglycerol 33 vs 9%, P<0.01). Plasminogen activator inhibitor-1 (PAI-1) and factor VII (fVII) levels decreased more during consumption of oat bran compared with the control period (PAI-1: 30 vs 2.3%, P<0.01; fVII: 15 vs 7.6%, <0.001). Fecal volume and dry matter were greater when consuming the oat bran diet compared with the control (P<0.001), and energy excretion was increased by 37% (1014 vs 638 kJ/day, P<0.001); however, changes in body weight did not differ (oat bran:-0.3±0.5 kg; control: 0.0±0.7 kg). Addition of oat bran (6 g soluble fiber/day) to a low-fiber diet lowered total and non-HDL cholesterol, as well as hemostatic factors, and may affect energy balance through reduced energy utilization.