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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #338236

Title: Association between plasma phenolics and improved cognition in blueberry-supplemented older adults

item Miller, Marshall
item SANDHU, AMANDEEP - Illinois Institute Of Technology
item BURTON-FREEMAN, BRITT - Illinois Institute Of Technology
item Shukitt-Hale, Barbara

Submitted to: Berry Health Benefits Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 2/10/2017
Publication Date: 3/28/2017
Citation: Miller, M.G., Sandhu, A., Burton-Freeman, B., Shukitt Hale, B. 2017. Association between plasma phenolics and improved cognition in blueberry-supplemented older adults [abstract]. 2017 Berry Health Benefits Symposium Pre-Proceedings, p. 88.

Interpretive Summary:

Technical Abstract: Research in both human and animals has demonstrated that cognitive function decreases during aging. These functional declines may be caused by long-term increases in and susceptibility to oxidative stress and inflammation. A growing body of research shows that dietary supplementation with blueberries can improve cognition during aging. Bioactive phenolic compounds, found in blueberries, are thought to play a role in this cognitive enhancement. In a recent clinical study conducted by our laboratory, healthy older adults (ages 60-75) were tested in a randomized, double-blind, placebo-controlled trial in which they consumed freeze-dried blueberry (equivalent to 1 cup blueberries) or placebo. Participants completed a battery of 8 cognitive tests and provided blood samples at baseline, and again following 45 and 90 days of intervention. Participants in the blueberry group showed enhanced executive function as evidenced by significantly fewer repetition errors in the California Verbal Learning test (CVLT-II; p = 0.031, 'p2 = 0.126) and a reduced switch cost on a task-switching test (p = 0.033, 'p2 = 0.09) across study visits, relative to controls. No significant effects were observed on the other tests. Fasting plasma concentrations of 30 anthocyanins and phenolic acids were measured as well as at 2 hours following breakfast, which included the supplement at follow-up visits. Hippuric acid, isovanillic acid, phloroglucinaldehyde, syringic acid, and ferulic acid-glucuronide concentrations were significantly altered as a result of blueberry consumption. Regression was used to assess the relationship between significantly altered concentrations of plasma phenolics and observed improvements in cognition. Among participants in the blueberry group, changes in CVLT-II repetition errors, from baseline to 90 days, were related to changes in fasting levels of hippuric acid and postprandial levels of syringic acid (p = 0.002; multiple r-squared: 0.552). Change in switch errors from baseline to 90 days was predicted by changes in postprandial levels of plasma ferulic acid-glucuronide (p = 0.031; multiple r-squared: 0.258). These findings show that the addition of easily achievable quantities of blueberry to the diets of older adults can improve some aspects of cognition, and improvements are related to changing levels of circulating polyphenols.