Role of bioprocessing in modifying cardiometabolic outcomes of an oat-based dairy alternative in a randomised controlled clinical intervention.
BACKGROUND & AIMS: A healthy diet rich in fibre-containing foods such as oats supports cardiometabolic health. Bioprocessing methods, including fermentation and enzymatic treatment, may further enhance the health benefits of oat-based foods by altering their physicochemical properties. The aims of this study were to investigate the effects of consuming fermented and non-fermented oat-based products enriched with fibre and protein on cardiometabolic outcomes gastrointestinal symptoms, and to consider how assessed physicochemical and nutritional differences between the products might relate to any observed effects. METHODS: In a 12-week randomised crossover trial, 56 adults with mild metabolic deterioration consumed fermented (gurt) and non-fermented (porridge) oat-based products enriched with fibre and protein as part of their habitual diet for three weeks each. The study products were specifically developed and prepared for this study using identical ingredients. Primary cardiometabolic factors and gastrointestinal symptoms (GSRS) were measured at four time points, while secondary outcomes were assessed at baseline and after both product periods. Physicochemical and nutritional characterization of the study products included cereal β-glucan (BG) and protein molecular weight distribution, starch and sugar analysis, microscopy, acidity, and viscosity. RESULTS: During the gurt consumption, non-high-density lipoprotein (non-HDL) and low-density lipoprotein (LDL) cholesterol concentrations decreased (-0.15 ± 0.51 mmol/L, p = 0.028; and -0.12 ± 0.46 mmol/L, p = 0.047, respectively), with a minimal impact on blood pressure and GSRS scores. Additionally, ferritin was lower after the gurt compared with baseline (-4.00 [-16.50, 6.25] μg/L, p = 0.015). Similarly, ferritin levels were lower after the porridge period (-7.50 [-20.50, 4.25] μg/L), accompanied with a modest decrease in blood pressure and HbA1c. These effects, however, did not substantially differ between the product periods. Insulin showed a significant sequence effect (psequence∗time <0.05) and was analysed in sequence groups. Insulin levels significantly decreased during the gurt consumption in the group that started with the porridge (-2.22 ± 6.16 mU/L, p = 0.015). Fermentation and enzymatic treatment induced significant changes in BG MW, starch, and composition in the gurt, which may alongside with increased fibre intake during the intervention explain the observed results. CONCLUSION: Consuming a fermented, oat-based gurt as part of habitual diet may improve cholesterol metabolism, likely due to increased oat fibre intake rather than fermentation as such. Moreover, greater intake of oat-based products, regardless of processing, can reduce ferritin concentrations and marginally improve other cardiometabolic factors. The study was registered in ClinicalTrials.gov as NCT06393114.