Wheat bran with reduced particle size does not affect gut health and systemic health in normal weight and obese subjects

Wheat bran (WB) consumption has been associated with improved gastrointestinal (GI) health and a reduced risk for metabolic disorders. Reducing the particle size of WB decreases its bulking effect but increases its fermentability. We investigated whether WB with reduced particle size (WB RPS) still affects gut and systemic health. In addition to normal weight (NW) subjects, obese (OB) subjects were included because of their presumed suboptimal health. During 1 month, 36 NW (BMI 22 ± 1.23 kg/m²) and 14 OB subjects (BMI 33 ± 2.13 kg/m²) daily consumed 20 g WB RPS or placebo (PL). Before and after the intervention, faecal wet weight and % dry matter, fat excretion, stool consistency (Bristol Stool Score) and faecal SCFA concentrations were quantified. Total GI transit was measured using 3H-PEG and expressed as % 3H recovered. Intestinal permeability was assessed using a 24 h 51Cr-EDTA urinary excretion test. Total cholesterol (TC) and triglyceride (TG) levels and C-reactive protein (CRP) levels were measured in blood as parameter of lipid metabolism and systemic inflammation, respectively. Baseline parameters were compared between NW and OB subjects using a Mann Whitney U test. A two-way ANCOVA was performed to compare the effect of the WB and PL intervention between both BMI groups. A significance level p