Aronia melanocarpa berries are rich in antioxidants and possess a high antioxidant capacity. Aronia berries have shown potential in type 2 diabetes mellitus (T2DM) treatment, and previous studies indicate improvements in glycemia after supplementation. Unfortunately, the effectiveness of aronia berries is limited by the low bioavailability of aronia, which fermentation could potentially overcome. The objective of this study was to compare the effects of fermented or non-fermented aronia pulp with placebo in subjects with T2DM. This study was a triple-blinded, triple-crossover study with eight-week intervention periods with fermented aronia extract (FAE), non-fermented aronia extract (AE), and placebo. Extracts were incorporated in snack bars with 37% aronia (FAE or AE) or wheat bran (placebo) and 63% raisins and coconut oil. Pre- and post-treatment period, we did fasting blood samples, including hemoglobin A1c, fructosamine, insulin, glucose, glucagon-like peptide-1, glucose-dependent insulinotropic peptide (GIP) and glucagon, oral glucose tolerance tests, and anthropometric measurements. Of 36 randomized participants, 23 completed the trial. Aside from a higher increase in GIP after FAE supplementation compared to after placebo supplementation, aronia extracts had no effect. The increase in GIP levels after FAE supplementation may hold potential benefits, but the overall clinical impact remains unclear.
Keywords: Aronia melanocarpa; anthocyanins; antioxidants; dietary supplement; polyphenols; randomized controlled trial; type 2 diabetes.