"Cognitive function is a key determinant of independence and quality of life among older adults," said Sheau Ching Chai, lead author of the study.
"The potential beneficial effects of tart cherries may be related to the bioactive compounds they possess, which include polyphenols, anthocyanins, and melanin," said Chai.
"They may also be related to tart cherry's potential blood-pressure-lowering effects, outlined in a previous study we conducted in the same population, as blood pressure can influence the blood flow to the brain," added Chai.
In the randomised controlled trial, 34 participants were assigned to consume either 16 ounces (480 mL) of montmorency tart cherry juice or the same amount of a placebo drink, half in the morning and a half in the evening, every day for 12 weeks.
All participants were generally healthy and were not taking any medications that could affect brain function and were asked to maintain their regular diet and physical activity levels for the duration of the study.
Before and after the 12-week trial, researchers analysed the cognitive function and subjective memory scores via a series of questionnaires and tests.
After 12 weeks, those drinking montmorency tart cherry juice exhibited improved scores in both cognitive function and subjective memory. Specifically, the tart cherry group showed a five per cent increase in satisfaction with their ability to remember things, a four per cent reduction in movement time (a measurement of speed of response to visual stimuli) and a 23 per cent reduction in errors made during an episodic visual memory task (which assesses visual memory and new learning) compared to placebo.
They also exhibited a three per cent improvement in visual sustained attention (which measures visual information processing) and an 18 per cent reduction in errors made during a spatial working memory task (which assesses memory and strategy use) compared to baseline values.
Compliance rate throughout the 12-week trial was high (94.2 per cent), suggesting tart cherry juice twice a day was a manageable addition to these participants' daily routine.