This study investigates the plasma metabolic effectiveness from 3.3 g mixed linkage barley or oat β-glucan fibre per day by 1H NMR spectroscopy on plasma samples and multivariate data analysis. Three large-scale extracted, equally sized but structurally different β-glucans, were tested in a blinded randomised cross-over design using young healthy adults, where the β-glucans were compared to a non-fibre control during a 21 day dietary intervention period. Subject variance was found to dominate the metabolomics data although the variations in subject age and BMI was very small. The second most influential variation was found to be due to gender as characteristic lipoprotein profiles were found for male and female samples. The 3.3 g/d did not perturb the blood homeostasis in healthy adults as no systematic differences between 3-week β-glucan treatments and control was found. The present study constitutes the first metabolomic β-glucan human intervention study which proves complementary and confirmatory with respect to previous nutritional investigations evaluating traditional cardiovascular disease risk markers.