Daily consumption of Concord grape juice may enhance cognitive function in people under stress, according to a new study published in the American Journal of Clinical Nutrition. The researchers suggest the benefits are likely result from the high concentration of polyphenols in Concord grape juice.
Polyphenol compounds found in berry fruits, in particular flavonoids, have been associated with health benefits including improvement in cognition and neuronal function with aging. Concord grape juice contains polyphenols, including anthocyanins and flavanols, and previous research has shown improvement in a number of human health conditions with grape juice supplementation.
Because increased stress can impair cognitive function and elevate blood pressure researchers at the University of Leeds examined the potential beneficial effect of Concord grape juice consumption in individuals with somewhat stressful and demanding lifestyles.
For the study, researchers enrolled 25 healthy mothers (aged 40 to 50 years old) of preteen children who were employed for ≥30 hour/week. They consumed 12-ounces of either Concord grape juice (containing 777 mg total polyphenols) or an energy-, taste- and appearance-matched placebo daily for 12 weeks, according to a randomized crossover design with a four-week washout. Verbal and spatial memory, executive function, attention, blood pressure and mood were assessed at baseline and at six and 12 weeks. Immediately after the cognitive battery, a subsample of 17 women completed a driving performance assessment at the University of Leeds Driving Simulator. The 25-minute driving task required participants to match the speed and direction of a lead vehicle.
Significant improvements in immediate spatial memory and driving performance were observed after Concord grape juice consumption relative to placebo. There was evidence of an enduring effect of Concord grape juice such that participants who received the juice in phase one maintained better performance in the placebo phase.
The researchers concluded that the cognitive benefits associated with the long-term consumption of flavonoid-rich grape juice are not exclusive to adults with mild cognitive impairment. Moreover, these cognitive benefits are apparent in complex everyday tasks such as driving. Effects may persist beyond the cessation of flavonoid consumption, and future studies should carefully consider the length of washout within crossover designs.
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