Data published in the European Journal of Nutrition indicated that a 240 ml glass of the flavonoid-rich orange juice was associated with significantly improved scores for attention, executive function, and psychomotor speed in healthy middle-aged men without mild cognitive impairment six hours after consumption, compared with placebo.
“It is important to acknowledge that orange juice consumption was not associated with a significant improvement on every individual cognitive test; this would not be expected given that the effects of nutritional interventions on cognitive performance are small and difficult to detect in healthy adults,” wrote the researchers.
“However, consistently higher means were observed following orange juice relative to the placebo in the vast majority of outcomes.”
The researchers recruited 24 healthy men aged between 30 and 65 to participate in their randomized, double-blind, crossover study. The men were randomly assigned to consumer orange juice containing 272 mg of flavonoid or a calorie-matched placebo, with the interventions separated by two weeks.
A battery of tests revealed that, compared to placebo, the flavonoid-rich orange juice was associated with significantly better performance on tests of executive function and psychomotor speed.
Alertness was also reportedly improved following orange juice consumption.
Bioavailability data would suggest that the cognitive benefits observed after six hours are related to the flavanones hesperidin and narirutin, said the researchers.
“One plausible hypothesis is that flavonoid consumption may lead to acute cognitive benefits via increased [cerebral blood flow] as a result of enhanced endothelial function and increased bioavailability of nitric oxide,” they wrote. “Human studies show significantly increased [cerebral blood flow] several hours following cocoa flavanol consumption. These are supported by chronic studies which show increased activation in the right middle prefrontal cortex and the right superior parietal cortex following anthocyanin and flavanol-rich grape juice consumption.
“Moreover, increased steady-state-evoked potentials in posterior parietal and central–frontal regions and increased [cerebral blood flow] in the hippocampus during a spatial memory task have been observed following several weeks daily consumption of cocoa flavanols. As yet, there are no published data examining peripheral or [cerebral blood flow] in humans following flavanone consumption; therefore, these potential mechanisms are speculative at this time.
To conclude, the authors stated: “These data demonstrate that fruit juice-based flavonoids can acutely enhance cognition in healthy adults. This is consistent with the accumulating evidence from chronic interventions and epidemiological research that increased consumption of fruits, fruit juices and other flavonoid-rich foods over the lifespan is associated with cognitive benefits such as a reduced risk of neuropsychological disease, attenuation of aging-induced cognitive decline and maintenance of optimal cognitive facilities.”
Source: European Journal of Nutrition
September 2016, Volume 55, Issue 6, pp 2021–2029
“Flavonoid-rich orange juice is associated with acute improvements in cognitive function in healthy middle-aged males”
Authors: M.H. Alharbi et al.