Can a daily dose of fruit help prevent dementia? A new study suggests that consuming a cup of strawberries every day could reduce the risk of dementia in middle-aged individuals.
A research team from the University of Cincinnati found last year that adding blueberries to the diet helps reduce dementia risk. In the current study, an extension of the blueberry research, the researchers looked at the impact of strawberry supplementation on cognitive aging. The results were published in the journal Nutrients.
Dementia is the impaired ability to think, memorize, or make decisions. Alzheimer's disease is the most common form of dementia, accounting for around 80% of cases.
"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. There is epidemiological data suggesting that people who consume strawberries or blueberries regularly have a slower rate of cognitive decline with aging," said study author Robert Krikorian, professor emeritus in the UC College of Medicine's Department of Psychiatry and Behavioral Neuroscience, in a news release.
In addition to the anthocyanins, strawberries have added benefits of micronutrients called ellagitannins and ellagic acid, bioactive compounds associated with positive effects on conditions such as cardiovascular diseases, neurodegenerative syndromes, and cancer.
A 12-week trial was conducted on 30 overweight patients with complaints of mild cognitive decline. During the trial, the participants were asked to abstain from eating any berry fruit except a daily packet of supplement powder given to them. Half of the participants were given a strawberry supplement equivalent to one cup of whole strawberries, while the other half received a placebo.
The team then assessed the participant's cognitive abilities, including long-term memory, mood, intensity of depressive symptoms, and metabolic data.
"Those in the strawberry powder group had diminished memory interference, which is consistent with an overall improvement in executive ability," the researchers wrote in the news release.
"Reduced memory interference refers to less confusion of semantically related terms on a word-list learning test. This phenomenon generally is thought to reflect better executive control in terms of resisting intrusion of non-target words during the memory testing," Krikorian explained.
The researchers also noted a significant reduction in depressive symptoms. However, there was no effect observed on metabolic measures, including insulin levels.
The beneficial effect on dementia is believed to be due to the inflammation-reducing properties of strawberries. "Executive abilities begin to decline in midlife and excess abdominal fat, as in insulin resistance and obesity, will tend to increase inflammation, including in the brain. So, one might consider that our middle-aged, overweight, prediabetic sample had higher levels of inflammation that contributed to at least mild impairment of executive abilities. Accordingly, the beneficial effects we observed might be related to the moderation of inflammation in the strawberry group," Krikorian said.
