Abstract
BACKGROUND: Antioxidants and prebiotics are popular functional foods known for their distinct physiological ameliorating benefits on type 2 diabetes mellitus (T2DM). Whether and how a combined antioxidant-prebiotic supplement affects primary and secondary T2DM outcomes is not known. OBJECTIVES: We investigated the therapeutic effects of an antioxidant (anthocyanin from riceberry rice) combined with prebiotics (dietary fibre from rice bran and Jerusalem artichoke) on glucose control, lipid profile, oxidative stress, inflammation, and cardiorespiratory fitness in T2DM patients. METHODS: A total of 60 T2DM patients were randomly assigned to receive antioxidant/prebiotic (supplement group, SG) or maltodextrin (control group, CG), (two capsules (350 mg)/meal after three meals and before bedtime, 2.8 g/day), for 60 days. Venous blood samples were collected at baseline and after 60 days intervention to assess blood metabolic variables (glucose, insulin, and lipid profiles, renal and liver functions, oxidative stress, inflammation). Nutrition status, anthropometry, body composition (DEXA) and cardiorespiratory fitness were also measured. RESULTS: Analysis of co-variance showed superior effects on T2DM's glucose and lipid profiles in the SG compared with the CG including reduced fasting blood glucose (p = 0.01 within-group effects, p = 0.03 interaction effects), reduced glycated haemoglobin (p = 0.004 within-group effects, p = 0.002 interaction), and reduced low density lipoprotein (p = 0.006 within-group effects, p = 0.02 interaction effects). No significant change was found within the CG for any of these parameters. Kidney function's glomerular filtration rate was also improved in the SG (p = 0.01 within-group effects), but not in the placebo CG. Intermediatory biomarkers of oxidative stress, inflammation, and cardiorespiratory fitness were not significantly affected in either group with no interaction effects. No adverse effects were detected following the 60-day supplementation intervention. CONCLUSIONS: The findings suggest that a combined anthocyanin-fibre may be promoted as an adjacent therapy in patients with T2DM, but the intermediary mechanisms of action require further research.