Food anthocyanins decrease concentrations of TNF-α in older adults with mild cognitive impairment: A randomized, controlled, double blind clinical trial.

BACKGROUND & AIMS: Vascular function, blood pressure and inflammation are involved in the pathogenesis of major chronic diseases, including both cardiovascular disease (CVD) and mild cognitive impairment (MCI). This study investigated the effects of food anthocyanins on microvascular function, 24-h ambulatory blood pressure (ABP) and inflammatory biomarkers in older adults with MCI. METHODS AND RESULTS: Thirty-one participants with MCI [19 female, 12 male, mean age 75.3 (SD 6.9) years and body mass index 26.1 (SD 3.3) kg/m2], participated in a randomized, controlled, double-blind clinical trial (Australian New Zealand Clinical Trials Registry: ACTRN12618001184268). Participants consumed 250 mL fruit juice daily for 8 weeks, allocated into three groups: a) high dose anthocyanins (201 mg); b) low dose anthocyanins (47 mg); c) control. Microvascular function (Laser Speckle Contrast Imaging combined with a post-occlusive reactive hyperaemia test), 24h ABP and serum inflammatory biomarkers were assessed before and after the nutritional intervention. RESULTS: Participants in the high anthocyanins group had a reduction in serum tumor necrosis factor alpha (TNF-α) (P = 0.002) compared to controls and the low anthocyanins group (all P's > 0.05). Serum IL-6, IL-1ß, c-reactive protein, and parameters of microvascular function and 24h ABP were not altered by any treatment. CONCLUSION: A daily high dose of fruit-based anthocyanins for 8 weeks reduced concentrations of TNF-α in older adults with MCI. Anthocyanins did not alter other inflammatory biomarkers, microvascular function or blood pressure parameters. Further studies with a larger sample size and longer period of follow-up are required to elucidate whether this change in the immune response will alter CVD risk and progression of cognitive decline.

Anthocyanin intake is associated with improved memory in older adults with mild cognitive impairment.

Research on the role of dietary anthocyanins in preventing cognitive decline in older adults shows promise. This study investigated the association between usual anthocyanin intake and indices of memory and cognition in 40 older adults diagnosed with mild cognitive impairment that were recruited to a randomized clinical trial. It was hypothesized that daily anthocyanin intake would be similar to healthy older adults and that higher anthocyanin intake would be associated with better cognitive performance. Cognitive performance was assessed using a battery of tests including the Rey Auditory Verbal Learning Test (RAVLT). Dietary intake was assessed through 3-day food records and anthocyanin intake was quantified using the PhenolExplorer food composition database. Multivariate linear regression compared differences in cognitive performance between higher (>10 mg/d) and lower consumers (<10 mg/d). Overall, participants had low median intake of anthocyanins (5.3; interquartile range [IQR], 32.1 mg/d), with the lower consumer group eating negligible anthocyanins (median, 0.13; IQR, 1.5 mg/d), and the higher consumer group eating above the national average (median, 35.5; IQR, 71.5 mg/d). On the RAVLT, the higher anthocyanin consumer group recalled a greater number of words after a short delay and a distracter task (B, 2.07; standard error [SE], 0.93; 95% confidence interval [CI], 0.18-3.96; P = .03) and longer delay of 20 minutes (B, 2.68; SE, 1.11; 95% CI, 0.43-4.94; P = .02); and forgot less words after a long delay of 20 minutes (B, -2.63; SE, 0.63; 95% CI, -3.90 to -1.35; P< .001). Further investigation of the protective role of the usual consumption of dietary anthocyanins for memory and cognition in pathological and normal aging appears warranted. Trial registration: This cross-sectional study uses baseline data from a randomized controlled trial registered with the Australian New Zealand Clinical Trials Registry (ACTRN12618001184268).