The research was published recently in the European Journal of Nutrition. It was conducted by researchers from the Illinois Institute of Technology, the University of Cincinnati and the University of Reading in the UK.
Blueberry polyphenols shown to have positive effects in other age groups
The researchers said wild blueberry (WBB) consumption has been shown in past research to benefit cognitive and metabolic measures in children and young adults. The goal of the present research was to confirm the same held true for middle aged adults.
To test the hypothesis, the researchers recruited 35 subjects between the ages of 43 and 59, 12 of whom were male and 23 of whom were females. They ran the gamut in weight from a low BMI of around 23 to as much as 31. All had blood pressure within the normal range.
The randomized investigator- and subject-blinded, 2-arm, placebo-controlled, cross-over trial had participants ingest a drink that was equivalent to one cup of WBB or placebo on two occasions as part of a breakfast meal. Then they completed cognitive tasks and had blood drawn before and at regular intervals for eight hours after each meal/treatment. Changes in episodic memory and executive function (EF) were assessed alongside plasma levels of glucose, insulin, and triglyceride.
The study material was freeze dried wild blueberry powder supplied by the Wild Blue Berry Association of North America, located in Old Town, MA. The blueberries were freeze dried and packaged by FutureCeuticals in Momence, IL. The trial was sponsored by the Clinical Nutrition Research Center, Illinois Institute of Technology.
The subjects performed cognitive tests at arrival at the test facility. Then they consumed a breakfast meal with the test drink or placebo 30 minutes later. They performed four more rounds of cognitive tests as well as undergoing nine total blood draws while participating. They were also served a lunch containing a low amount of polyphenols and a snack while participating in the all-day test.
The cognitive tests involved included remembering word lists in which new, ‘foil’ words were added to subsequent presentations. The participants also did rapid response tests such as quick ‘go no-go’ tests in which a black rectangle was shown followed by a go or no-go color stimulus.
Polyphenols boost cognitive responses, improve metabolic response to meal
The researchers found the WBB group improved on cognitive tasks in the two hours after ingesting the drink. Their metabolic response to the meal was improved as well. The differences between the groups declined thereafter.
“The findings provide further support for the efficacy of wild blueberry on improving cognitive outcomes within this age group, particularly where there is increased cognitive demand. Wild blueberry was also found to reduce glucose and insulin concentrations in response to a meal over the initial 120 min having implications for post-meal metabolic control. Although there was little evidence of a direct relationship on cognition, these data have importance for structuring meal plans to reduce the metabolic burden in individuals with glucose homeostasis concerns,” they concluded.
Source: European Journal of Nutrition
DOI: 10.1007/s00394-020-02336-8
Improved metabolic function and cognitive performance in middle-aged adults following a single dose of wild blueberry
Authors: Whyte AR, et al.