Late-life dementia is a growing public health concern lacking effective treatment. Neurodegenerative disorders such as Alzheimer’s disease develop over a preclinical period of many years beginning in midlife. The prevalence of insulin resistance, a prominent risk factor for late-life dementia, also accelerates in middle-age. Consumption of berry fruits, including strawberries, has been shown to influence metabolism as well as cognitive performance suggesting potential to mitigate risk for dementia. In a new study, scientists at the University of Cincinnati enrolled overweight middle-aged men and women with insulin resistance and subjective cognitive decline and performed a 12-week intervention with daily administration of whole-fruit strawberry powder. Their findings support the notion that strawberry supplementation has a role in dementia risk reduction when introduced in midlife.
Krikorian et al. showed that daily supplementation with 13 g whole fruit strawberry powder reduced interference in memory and depressive symptoms in overweight middle-aged individuals. Image credit: Robert Owen-Wahl.
Alzheimer’s disease (AD) is the most common form of dementia, accounting for up to 80% of cases, and current projections indicate that AD will reach epidemic proportions during the next several years.
Paralleling the increase in dementia prevalence is an equally disturbing rise in metabolic disturbance reflected in insulin resistance, hyperinsulinemia, obesity, and related health conditions associated with late-life dementia.
There is no remedy for dementia, and it is not clear when or if effective therapy will be available.
Accordingly, prevention and mitigation of risk have been increasingly emphasized.
“Both strawberries and blueberries contain antioxidants called anthocyanins, which have been implicated in a variety of berry health benefits such as metabolic and cognitive enhancements,” said University of Cincinnati’s Professor Robert Krikorian.
“There is epidemiological data suggesting that people who consume strawberries or blueberries regularly have a slower rate of cognitive decline with aging.”
“In addition to containing anthocyanins, strawberries contain additional micronutrients called ellagitannins and ellagic acid that have been associated with health benefits.”
“About 50% of individuals in the U.S. develop insulin resistance, commonly referred to as prediabetes, around middle age, which has been shown to be a factor in chronic diseases.”
“The metabolic and cardiovascular benefits of strawberry consumption have been studied previously, but there were relatively few studies on its cognitive effects.”
“We assessed whether strawberry consumption might improve cognitive performance and metabolic health in this population and, if so, whether there might be an association between cognitive enhancement and reduced metabolic disturbance.”
The study involved a total of 30 overweight patients between 50-65 years old with complaints of mild cognitive decline.
Over a period of 12 weeks, the participants were asked to abstain from berry fruit consumption of any kind except for a daily packet of supplement powder to be mixed with water and consumed with breakfast.
Half of the participants received powders that contained the equivalent of one cup of whole strawberries (the standard serving size), while the other half received a placebo.
The participants were given tests that measured certain cognitive abilities like long-term memory.
The researchers also tracked their mood, intensity of depressive symptoms and metabolic data over the course of the study.
Those in the strawberry powder group had diminished memory interference, which is consistent with an overall improvement in executive ability.
“Reduced memory interference refers to less confusion of semantically related terms on a word-list learning test,” Professor Krikorian said.
“This phenomenon generally is thought to reflect better executive control in terms of resisting intrusion of non-target words during the memory testing.”
“The strawberry-treated participants also had a significant reduction of depressive symptoms, which can be understood as a result from enhanced executive ability that would provide better emotional control and coping and perhaps better problem-solving.”
“Other strawberry studies have found improvement in metabolic measures including lower insulin, but there was no effect found on the patients’ metabolic health in this study.”
“Those studies generally used higher dosages of strawberry powder than in our research, and this could have been a factor.”
The study was published in the journal Nutrients.
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Robert Krikorian et al. 2023. Early Intervention in Cognitive Aging with Strawberry Supplementation. Nutrients 15 (20): 4431; doi: 10.3390/nu15204431