A new research study published in Nutrients finds that blueberries have cognitive benefits. More specifically, the equivalent of half a cup of fresh blueberries per day, consumed as freeze-dried blueberry powder, was found to help middle-aged people combat cognitive decline when implemented early in people at risk.

This is an important finding given that in the United States, nearly six million older adults are living with dementia. Since there are limited treatments for cognitive decline, preventive approaches and risk mitigation through proper nutrition are becoming increasingly important. Since neurodegenerative changes associated with cognitive decline begin in middle age, this research indicates that blueberries may present an opportunity for early intervention by targeting modifiable risks such as poor nutrition and related metabolic disorders.

The randomized, double-blind, placebo-controlled trial, “Midlife Blueberry Supplementation for Dementia Risk Reduction,” examined the impact of blueberry supplementation in producing measurable cognitive benefits in the context of aging and resistance to insulin. Participants (n = 27) were overweight (BMI > 25) men and women aged 50 to 65 years with subjective cognitive impairment and moderate insulin resistance.

Over the course of 12 weeks, participants were randomly assigned to consume freeze-dried blueberry powder or placebo powder daily. Participants were asked to consume the powder with their morning or evening meal, mixing it with water. Pre- and post-intervention assessments of cognition and metabolism and exploratory measures of peripheral mitochondrial function were performed.

The blueberry group experienced better performance on measures of lexical access, such as letter fluency as measured by the Controlled Word Association task, better performance on measures of memory interference, such as fewer intrusive errors in recall as measured by the California Verbal Learning Test and reduced memory erosion of difficulty in activities of daily living, such as reduced forgetfulness as measured by the Daily Memory Questionnaire. The blueberry group also experienced correction of peripheral hyperinsulinemia, which is associated with neurodegeneration in the brain, as well as a significant decrease in fasting insulin levels.

Based on these findings, the study authors suggest that potential mechanisms for these findings may be associated with anthocyanins and proanthocyanidins, the bioactive flavonoid compounds found in blueberries and responsible for their vibrant blue color. Importantly, these results support that blueberries may induce metabolic and other benefits that could serve as an early intervention to prevent cognitive decline associated with aging.

“This is the first study of its kind to look at cranberry supplementation in middle-aged people at risk for future health problems and dementia in later life,” said Robert Krikorian, PhD, Department of Psychiatry and Behavioral Neuroscience, Academic Health from the University of Cincinnati. Center and principal investigator of the study. "Importantly, this research provides evidence that blueberry supplementation can improve cognitive function and correct high insulin levels in these prediabetic participants."

The study, which was funded by the US Highbush Blueberry Council, BB #: 162393, builds on previous research in this area, which has shown improved long-term memory performance with blueberry supplementation in older adults with impaired mild cognitive. It also supports previous research that found an association between blueberry consumption and improved metabolic function in people at risk, such as improved insulin sensitivity.

More research is needed to look at blueberry supplementation over a longer period of time, with a stronger sample size. Additionally, longitudinal cognitive evaluations would be valuable in assessing the influence of blueberries on the progression of cognitive decline and in further investigating the mechanisms of neurocognitive benefit.

"While further study is warranted, our results provide new and exciting data on the potential of blueberry supplementation as a preventive intervention," said Krikorian.

With Brain Health Month on the horizon in June, USHBC's personalized resources are now available in the Brain Health Toolkit, including ready-to-use content on social media and digital ads, tip sheets, research insight (including this study), delicious recipes, amazing blueberry pictures, and more.