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Improved metabolic function and cognitive performance in middle-aged adults following a single dose of wild blueberry.

  • 2020-08-03
  • European journal of nutrition 60(3)
    • Adrian R Whyte
    • Sajida Rahman
    • Lynne Bell
    • Indika Edirisinghe
    • Robert Krikorian
    • Claire M Williams
    • Britt Burton-Freeman

Study Design

Type
Randomized Controlled Trial (RCT)
Population
Thirty-five individuals aged 40-65 years
Methods
randomized, double blind, cross-over study; participants consumed a breakfast meal and 1-cup equivalent WBB drink or matched placebo beverage on two occasions; completed cognitive tasks and had blood drawn before and at regular intervals for 8 h after each meal/treatment
Blinding
Double-blind
Duration
8 h
  • Rigorous Journal

Purpose

Research has demonstrated cognitive benefits following acute polyphenol-rich berry consumption in children and young adults. Berry intake also has been associated with metabolic benefits. No study has yet examined cognitive performance in middle-aged adults. We investigated the relationships among cognitive and metabolic outcomes in middle-aged adults following wild blueberry (WBB) consumption.

Methods

Thirty-five individuals aged 40-65 years participated in a randomized, double blind, cross-over study. Participants consumed a breakfast meal and 1-cup equivalent WBB drink or matched placebo beverage on two occasions. Participants completed cognitive tasks and had blood drawn before and at regular intervals for 8 h after each meal/treatment. Changes in episodic memory and executive function (EF) were assessed alongside plasma levels of glucose, insulin, and triglyceride.

Results

Analysis of the memory-related Auditory Verbal Learning Task (AVLT) word recognition measure revealed a decrease in performance over the test day after placebo intake, whereas performance after WBB was maintained. For the AVLT word rejection measure, participants identified more foils following WBB in comparison to placebo. Benefits were also observed for EF on the Go/No-Go task with fewer errors following WBB intake on cognitively demanding invalid No-Go trials in comparison to placebo. Furthermore, in comparison to placebo, response times were faster for the Go/No-Go task, specifically at 4 h and 8 h following WBB treatment. We also observed reduced post-meal glucose and insulin, but not triglyceride, concentrations in comparison to placebo over the first 2 h following ingestion. Though the addition of Age, BMI, glucose and insulin as covariates to the analysis reduced the significant effect of beverage for AVLT word rejection, metabolic outcomes did not interact with treatment to predict cognitive performance with the exception of one isolated trend.

Conclusions

This study indicated acute cognitive benefits of WBB intake in cognitively healthy middle-aged individuals, particularly in the context of demanding tasks and cognitive fatigue. WBB improved glucose and insulin responses to a meal. Further research is required to elucidate the underlying mechanism by which WBB improves cognitive function.

Research Insights

  • Wild Blueberry→Improved Cognitive Function

    Furthermore, in comparison to placebo, response times were faster for the Go/No-Go task, specifically at 4 h and 8 h following WBB treatment.

    Effect
    Beneficial
    Effect size
    Small
    Dose
    1-cup equivalent WBB drink
  • Wild Blueberry→Improved Episodic Memory

    Analysis of the memory-related Auditory Verbal Learning Task (AVLT) word recognition measure revealed a decrease in performance over the test day after placebo intake, whereas performance after WBB was maintained.

    Effect
    Beneficial
    Effect size
    Small
    Dose
    1-cup equivalent WBB drink
  • Wild Blueberry→Improved Insulin Levels

    We also observed reduced post-meal glucose and insulin, but not triglyceride, concentrations in comparison to placebo over the first 2 h following ingestion.

    Effect
    Beneficial
    Effect size
    Small
    Dose
    1-cup equivalent WBB drink
  • Wild Blueberry→Reduced Post-meal Glucose

    We also observed reduced post-meal glucose and insulin, but not triglyceride, concentrations in comparison to placebo over the first 2 h following ingestion.

    Effect
    Beneficial
    Effect size
    Small
    Dose
    1-cup equivalent WBB drink
  • Wild Blueberry→Reduced Triglyceride Levels

    We also observed reduced post-meal glucose and insulin, but not triglyceride, concentrations in comparison to placebo over the first 2 h following ingestion.

    Effect
    Neutral
    Effect size
    Small
    Dose
    1-cup equivalent WBB drink
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