"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 study author Robert Krikorian, PhD, professor emeritus in the Department of Psychiatry and Behavioral Neuroscience in the University of Cincinnati, in a press release.
"There is epidemiological data suggesting that people who consume strawberries or blueberries regularly have a slower rate of cognitive decline with aging,” he added.
While studies show that strawberry consumption benefits cardiovascular health, relatively few studies have assessed its effects on cognition. In the current study, researchers thus sought to investigate the link between strawberry consumption and cognitive performance.
To do so, they enrolled 30 overweight patients aged between 50 and 65 years old with complaints of cognitive decline. Prof. Krikorian noted that this population has a higher risk of late-life dementia.
The participants were split into two groups of 15 and were asked to abstain from berry fruit consumption for 12 weeks. Both groups were then asked to consume a packet of supplement powder daily. While one group consumed powder containing the equivalent nutritional value of a cup of strawberries, the other group consumed a placebo equivalent.
Ultimately, the researchers found that participants who consumed strawberry powder experienced less memory interference- or 'less confusion of semantically related terms on a word-list learning test'. Prof. Krikorian said that such results are thought to reflect better executive control.
The researchers also found that participants who consumed strawberry supplement powder experienced fewer depressive symptoms. Prof. Krikorian noted that this may have been due to their "enhanced executive ability that would provide better emotional control and coping and perhaps better problem-solving."
"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," explained Dr. Krikorian.
"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 moderation of inflammation in the strawberry group," he continued.
Unlike other studies that have found that strawberry consumption improves metabolic measures- lowering insulin, for example- the researchers behind the present study found that strawberry supplement consumption had no effect on particpants' metabolic health. Prof. Krikorian noted that this may have come as other studies used higher doses of strawberry powder.
He concluded that future research should include larger participant samples and varying dosages of strawberry supplements. While the research authors declare no conflict of interest, the research was supported with funding from the California Strawberry Commission. The same commission also donated strawberry and placebo powders for the study.
Sources: Nutrients, Science Daily
