Improving Oxidative Stress Through a Wheat Aleurone-Rich Diet: Are Short-Chain Fatty Acids Possible Mediators?

Background/Objectives: Dietary fibers from cereals promote the production of short-chain fatty acids (SCFA), which have been linked to improved glucose and lipid metabolism, reduced inflammation, and decreased oxidative stress. Wheat aleurone, a bran fraction enriched in fermentable fibers and bioactive compounds, may enhance SCFA production, but clinical evidence remains limited. This study investigated whether a wheat aleurone-rich diet, compared with a refined wheat diet, modulates circulating SCFA concentrations and their relationship with oxidative stress in individuals at elevated cardio-metabolic risk. Methods: In a randomized, cross-over trial, 23 adults with abdominal obesity and at least one additional metabolic syndrome feature consumed isoenergetic diets enriched with wheat aleurone or refined wheat for 8 weeks. Fasting and postprandial serum SCFA concentrations were measured over 3 h following standardized test meals using the gas chromatography method. Urinary 8-isoprostane excretion was assessed as a biomarker of oxidative stress using the ELISA method. SCFA values are reported as changes (increase/decrease) from fasting values, calculated by subtracting the fasting value from that of each time point. Results: Compared with refined wheat, the wheat aleurone diet significantly increased postprandial butyrate response (p = 0.005, time × meal interaction), with higher values observed at 150 min (p = 0.027) and 180 min (p = 0.001). The mean change in postprandial butyrate was also greater after the wheat aleurone diet (+0.95 ± 1.92 vs. -0.32 ± 2.01 µmol/L; p = 0.040). Importantly, butyrate at 180 min was inversely correlated with urinary 8-isoprostane (r = -0.618, p = 0.019). No significant differences were found for acetate or propionate. Conclusions: A wheat aleurone-rich diet enhances postprandial butyrate production and is associated with lower oxidative stress, suggesting a role of butyrate in mediating the antioxidant benefits of wheat aleurone in individuals with cardio-metabolic risk. This study is registered under ClinicalTrials.gov Identifier no. NCT02150356.