Reviewed: Ahles S, Stevens YR, Joris PJ, et al. The effect of long-term Aronia melanocarpa extract supplementation on cognitive performance, mood, and vascular function: A randomized controlled trial in healthy, middle-aged individuals. Nutrients. 2020;12(8):2475. doi: 10.3390/nu12082475.
Age-associated cognitive decline is a natural process. Cognitive decline can be exacerbated by lifestyle-related risk factors and diseases, including being overweight, smoking, high blood pressure, diabetes, and diet. Genetic factors also play a role in the extent and rate of cognitive decline. Many pharmaceutical interventions for neurodegenerative disorders have significant side effects and limited efficacy. A 2017 systematic review of studies that assessed the effects of anthocyanin intake on cognitive outcomes found a beneficial effect of food-derived anthocyanins on acute and long-term cognition.1 Anthocyanins may improve cognitive performance by increasing levels of brain-derived neurotrophic factor (BDNF, a protein associated with learning and memory) and improving vascular health. Studies have shown that berries rich in anthocyanins may also suppress neuroinflammation and oxidative stress.
Black chokeberry (Aronia melanocarpa, Rosaceae), also known as aronia or aronia berry, has high concentrations of cyanidin-3-glycoside anthocyanins and has been the subject of studies on preventing and treating chronic diseases. The purpose of this randomized, double-blind, placebo-controlled parallel study was to determine the effects of long-term supplementation with A. melanocarpa extract (AME) on cognitive performance and mood in healthy, middle-aged, overweight adults. Secondary outcomes included evaluations of vascular function and BDNF levels.
Participants and Intervention
Healthy adults between 40 and 60 years old with a body mass index (BMI) between 25 and 35 kg/m2 were recruited for the study, which took place at the Metabolic Research Unit Maastricht (MRUM) of Maastricht University in Maastricht, the Netherlands. Participants were excluded if they had a history of chronic disease or major surgery, used medications that might interfere with the study, or took vitamin, mineral, or antioxidant supplements. Subjects who abused alcohol or drugs, were pregnant, smoked, or consumed dietary products containing anthocyanins also were excluded. The authors randomly assigned 101 participants to take either 90 mg AME (n = 34), 150 mg AME (n = 35), or placebo (n = 32). One participant from each group left the study due to starting a new medication, and one participant in the 150-mg AME group withdrew for personal reasons, but the available data from these individuals were included in the final analysis. The AME extract Brainberry® (BioActor BV; Maastricht) was used as the intervention. The 150-mg AME capsule contained 27 mg anthocyanins, and the 90-mg AME capsule contained 16 mg of anthocyanins and 60 mg of maltodextrin (Gonmisol SA; Barcelona, Spain). The placebo contained 150 mg of maltodextrin.
Study Design
Participants were instructed to take one capsule daily before breakfast with 200 mL of water. Participants also received a list of food products that contain high amounts of anthocyanins and were asked to abstain from consuming those products during the study period. Participants also were asked to refrain from vigorous exercise within two days of each test day. Participants completed a daily supplementation log, and any remaining capsules were returned to the study team and counted. At weeks 0, 6, 12, and 24, subjects completed cognitive tests, mood questionnaires, anthropometric measurements, and ultrasounds of the carotid artery. During each visit, participants took three different cognitive tests in the same order: the Stroop color and word test, the grooved pegboard test, and the number cross-out test. These tests assessed cognitive flexibility, psychomotor speed, and attention, respectively. Mood was assessed using a visual analog scale. Carotid ultrasound was performed and blood pressure was measured after participants rested in a reclined position for 15 minutes. Blood samples were collected and BDNF was measured at weeks 0, 6, 12, and 24. Alanine aminotransferase (ALT), alkaline phosphatase (ALP), bilirubin, and gamma-glutamyl transferase (GGT) were measured at weeks 0 and 24 to assess liver function.
Results
All groups were comparable in gender distribution, age, BMI, cognitive performance, and blood pressure at baseline. Researchers found no changes in liver function (ALT, ALP, bilirubin, and GGT levels) after 24 weeks of treatment. AME supplementation was well tolerated by participants. A significant treatment effect was observed for the dominant-hand score of the grooved pegboard test (P = 0.033). This test evaluates visual-motor coordination by measuring the time it takes to insert 25 grooved pegs into their respective slots. A significant improvement in dominant-hand grooved pegboard test scores from baseline was observed in the 90-mg AME group after correction for multiple testing (P = 0.009). (Correction for multiple testing is used to decrease the risk of false positive results.) A main effect of time was observed (P < 0.05); in other words, participants in all groups performed significantly better in the dominant-hand pegboard task after 24 weeks than at six weeks. No other results for dominant-hand scores were significant. No significant differences for any of the measures were observed for the non-dominant hand. The number cross-out test is a validated measure of attention in which, on a card with 800 numbers, certain numbers must be crossed out or underlined in a three-minute period. Researchers then analyze multiple factors on the completed cards: correct responses, incorrect responses, edited responses, and missed numbers. No significant differences among groups were observed in the cross-out test for (1) total correct/total incorrect responses or (2) total edited/total incorrect and missed responses. Post hoc analyses showed a combined mean time for both parameters was significantly higher at six weeks compared to 12 and 24 weeks (P < 0.05). No significant interaction or treatment effect was observed on the Stroop color and word test; however, a main effect of time was observed (P < 0.05). Post hoc analyses showed an overall time effect that was significantly higher at six weeks compared to 12 and 24 weeks (P < 0.05). No significant effects were observed for mood scores, BDNF concentrations for time and treatment interaction (or the effect of time and treatment independently), carotid elasticity, carotid intima-media thickness (cIMT), or ankle-brachial index (ABI). A significant treatment effect was observed for brachial diastolic blood pressure (P = 0.025). Post hoc analyses showed a significant difference in diastolic blood pressure between the 90-mg and 150-mg AME groups (P = 0.011). No statistically significant differences were observed for any of the other parameters.
Limitations and Conclusions
Several limitations to this study were noted, including incomplete cognitive testing and strong practice effects due to the repetitive test taking. The authors stated that because the “study contained three groups and four timepoints, correction for multiple testing had a massive impact on the conclusions.” Finally, the study did not examine potential synergistic effects of regular foods that contain high anthocyanin levels. The authors concluded: “AME could have a protective effect on cognition and blood pressure in healthy, middle-aged, overweight adults.” The authors recommend that future studies aim to isolate the mechanisms associated with the effects of black chokeberry on cognition. Additional studies should include participants with advanced cognitive decline.
Reference
- Kent K, Charlton KE, Netzel M, Fanning K. Food-based anthocyanin intake and cognitive outcomes in human intervention trials: A systematic review. J Hum Nutr Diet. 2017;30:260-274.