According to the findings, published in the journal Nutrients, a daily serving of strawberries for 12 weeks led to improved executive cognitive control and emotional coping in a small test group. The study attributed benefits to the anti-inflammatory action of the anthocyanins found in strawberries.
"Dementia is a general term that includes many different diseases, all without remedies," said Robert Krikorian, Ph.D., principal investigator and professor in the department of psychiatry at the University of Cincinnati Academic Health Center. "It is not clear when or if effective therapy will be available; prevention and mitigation through dietary and lifestyle choices is currently the best approach we have."
According to the Alzheimer’s Association, an estimated 6.7 million Americans over the age of 65 are currently living with Alzheimer's, the most common form of dementia.
Strawberries for dementia risk
The study builds on science supporting the potential of berries of all kinds to protect against cognitive decline, including Dr. Krikorian’s 2022 study demonstrating cognitive and metabolic benefits of blueberry supplementation in at-risk middle-aged adults. The body of research recognizes that late-life dementia typically begins in midlife and progresses over the years.
“We wanted to work with a middle-aged, overweight population as dementia is a condition that is believed to develop over a period of decades,” Dr. Krikorian said. “Furthermore, inflammation is likely a contributing factor related to metabolic disorders such as overweight/obesity, prediabetes and type 2 diabetes.”
He referenced preclinical data and prospective epidemiological evidence suggesting that strawberry supplementation can improve cognitive performance and diminish the rate of age-related cognitive decline. Additional research funded by the U.S. Department of Agriculture and California Strawberry Commission demonstrated that 90 days of strawberry powder supplementation improved cognitive performance and recognition memory in older adults. More recently, San Diego State University researchers associated two daily strawberry servings with enhanced speed of cognitive processing, lower blood pressure, reduced waist circumference and increased antioxidant capacity.
This latest double-blind, randomized controlled trial included 30 overweight adults between the ages of 50 and 65 years old (five men and 25 women) with signs of mild cognitive decline.
Participants received either a strawberry powder prepared from whole fruit or a control powder that included fiber but no polyphenolic content. Each 13-gram serving of strawberry powder contained 36.8 milligrams of anthocyanins derived from 130 grams of whole fruit (equivalent to about one cup of whole fresh strawberries).
A series of tasks assessed executive abilities including inhibitory control and task switching, lexical access, long-term memory function and mood. The researchers also evaluated metabolic and anthropometric parameters.
“We observed diminished memory interference and a reduction of depressive symptoms for the strawberry-treated participants; benefits consistent with improved executive ability,” the study reported. “However, there was no effect of the intervention on metabolic measures, possibly a consequence of the sample size, length of the intervention, or comparatively low anthocyanin dose.”
Of note, was the dramatic improvement in depression scores in the strawberry group, implying “a better ability to manage everyday activities and social relationships and improved response control and greater flexibility”, the researchers noted.
Commenting on the study, Chris Christian, senior vice president at the California Strawberry Commission, said: "We are excited with these findings and the future of polyphenol research. The link between strawberry consumption and brain health has been well explored in both clinical and population-based studies.”
The California Strawberry Commission provided the funding and the strawberry and placebo powders for the study.
“Early Intervention in Cognitive Aging with Strawberry Supplementation”
Authors: Robert Krikorian et al.