Drink 2-3 glasses of red grape juice every day and within 12 weeks your brain will be better at absorbing new information, according to the results of research done by psychiatrists at the University of Cincinnati.
Alzheimer's is fast becoming an epidemic. There are already twenty million earthlings suffering from this brain disease and according to the World Alzheimer Reports this figure will double every twenty years. There's no known medicine for this disease, so scientists are assessing the potential of various anti-Alzheimer's foods.
Epidemiological studies have shown the positive effects of the Willett diet, based on large amounts of vegetables and fish and low amounts of junk food, full-fat dairy products and red meat. In addition, small human trials have shown promising results with a low-carb diet or a diet containing polyphenol-rich berry juice.
In 2010 researchers at the University of Cincinnati published in the British Journal of Nutrition the results of a small experiment based on 15 healthy elderly people, average age 78, with failing memory. The elderly subjects drank 2-3 glasses a day of red grape juice for twelve weeks. To be more exact: they drank juice made from Concorde grapes, sold in the US as Welch's Grape Juice. The manufacturer, Welch Foods, funded the research.
Red grape juice contains small amounts of resveratrol. More important components are probably the anthocyanins [structural formula below right] and proanthocyanidins [structural formula below left]. Proanthocyanidins can be large molecules, consisting of six building blocks. In the intestine micro-organisms chop these polymers into smaller pieces that the body can absorb. These compounds are also found in cheap supplements like Grape Seed Extract.
Before and after the supplementation the researchers tested the memory of their subjects, using the California Verbal Learning Test [CVLT] and the Spatial Paired Associate Learning Test [SPALT]. The scores of the seven subjects who drank a placebo juice did not improve; the scores of the five subjects who drank the real stuff did improve.
The insulin level of the subjects in the Concord grape-juice group rose. The researchers suspect that the phenols in the juice enhanced the working of the insulin and the insulin producing cells.
They don't know how the substances in red grapes improve the memory. It may be that the substances widen the blood vessels, so that more oxygen and glucose gets to the brain. It may be that the substances reduce inflammatory processes in the brain, thus slowing down neurological aging processes.
"The major limitation of the present study was the small sample size, which limited power to detect differences", the researchers conclude. "However, the moderate to large effect sizes indicate that it would be worthwhile to conduct larger trials to evaluate the neurocognitive benefits and putative mechanisms of Concord grape juice supplementation in pre-dementia conditions."
Br J Nutr. 2010 Mar;103(5):730-4.