Magnetic resonance imaging (MRI) of the brains of the study participants also revealed that 16 weeks of drinking a glass of Welch’s Concord grape juice every day led to greater activation in select parts of the brain, suggesting increased blood flow, according to findings published in the Journal of Agricultural and Food Chemistry .
“The findings provide further indications that polyphenol-rich Concord grape juice supplementation has benefit for neurocognitive function in older adults with mild memory decline,” wrote researchers from University of Cincinnati and Welch Foods.
“For the first time, we show preliminary data indicating increased neural activation in cortical regions along with improved memory function in this population.”
Strengthening the science
Concord grape juice is a rich source of polyphenols, potent antioxidants that 'mop up' harmful reactive oxygen species that have been identified as key to the aging process.
The new study, led by Dr Robert Krikorian from the University of Cincinnati Academic Health Center, adds to previous findings in both rats and humans.
A study by Tufts researchers reported that Concord grape juice appeared to reverse the course of neuronal and behavioral aging in rats (Nutrition, 2006, Vol. 22, pp. 295-302), while a study by Dr Krikorian’s group found that daily consumption of Concord grape juice may enhance memory in older people with mild impairment in the brain function (British Journal of Nutrition, 2010, Vol. 103, pp 730-734).
For the new study, Dr Krikorian and his co-workers recruited 21 people with an average age of 76. All of the participants had mild cognitive impairment. Participants were randomly assigned to receive either a placebo beverage of Concord grape juice at a dose related to their body weight, and equivalent to 6.3-7.8 ml/kg. The heavier the person, the greater the dose, so someone weighing between 45 and 57 kg would receive 355 ml/day, for example, while someone weighing between 83 and 95 kg would get 621 ml/day.
Results showed that consumption of the grape juice was associated with fewer errors in memory tasks, compared with placebo.
In addition, MRI scans showed significantly greater activation in anterior and posterior regions on the right side of the brain.
“Increased regional fMRI activation represents greater hemodynamic response, which would be consistent with observations of vascular benefit associated with grape juice supplementation, and greater hemodynamic response is strongly associated with increased neuronal activity,” wrote the researchers.
“In future studies, the inclusion of different dosing conditions and intervention periods to assess the possibility of over- and underdosing will be essential.
“It will be of interest to compare lower doses and briefer interventions with moderate to high dosing for longer duration such as that employed in our trial.”
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, ASAP Article, DOI: 10.1021/jf300277g
“Concord Grape Juice Supplementation and Neurocognitive Function in Human Aging”
Authors: R. Krikorian, E.L. Boespflug, D.E. Fleck, A.L. Stein, J.D. Wightman, M.D. Shidler, S. Sadat-Hossieny