January 26, 2010 — Daily consumption of commercially available wild blueberry juice improves neurocognitive function in older adults with early memory decline, new research suggests.
In the first human trial to assess blueberry supplementation on neurocognitive function in older adults, investigators at the University of Cincinnati Academic Health Center in Ohio found that after 12 weeks of consuming 2 to 2? cups of wild blueberry juice daily, study subjects showed significant improvement on memory and learning tests compared with their matched counterparts who consumed a placebo beverage.
"The findings of this preliminary study suggest that moderate-term blueberry supplementation can confer neurocognitive benefit and establish a basis for more comprehensive human trials to study preventive potential and neuronal mechanisms," the study authors, led by Robert Krikorian, PhD, write.
The study was published online January 4 in the Journal of Agriculture and Food Chemistry.
Antidepressant Effect Assessed
The investigators point out that previous studies in laboratory animals suggest that eating blueberries may help boost memory in elderly individuals. Until now, however, there has been little scientific work aimed at testing the effect of blueberry supplementation in humans.
To assess the hypothesis that blueberry consumption may have a beneficial effect on memory in older adults, the investigators conducted the 12-week trial, which involved daily supplementation with wild blueberry juice in 9 subjects (5 men and 4 women) 70 years and older who had mild, acquired memory decline.
The study's primary outcomes were measures of memory function, including the Verbal Paired Associate Learning Test and the California Verbal Learning Test.
Alternate forms of these memory tests were used at baseline and at the final 12-week visit to mitigate practice effects associated with using the same test twice.
The investigators also assessed the potential impact of blueberry juice on mood using the Geriatric Depression Scale and also measured weight and waist circumference and assessed serum glucose and insulin values by obtaining fasting blood samples.
Preventive Intervention?
"At 12 weeks, improved paired associate learning (p = 0.009) and word list recall (p = 0.08) were observed," the study authors report. They also noted trends toward reduced depressive symptoms and lower glucose levels.
Although the sample size was small, the investigators note that the effect sizes were moderate to large for both the primary and secondary outcomes.
"These preliminary memory findings are encouraging and suggest that consistent supplementation with blueberries may offer an approach to forestall or mitigate neurodegeneration," the study authors write.
"On balance," they add, "this initial study establishes a basis for further human research of blueberry supplementation as a preventive intervention with respect to cognitive aging."
The study was supported by the Wild Blueberry Association of North America and the National Institutes of Health. The authors have disclosed no relevant financial relationships.
J Agric Food Chem. Published online January 4, 2010.
