An article appearing online in advance of the publication of the September, 2009 issue of the Journal of Alzheimer's Disease revealed that regular intake of grape seed polyphenols effectively elevates plasma and brain levels of the compounds. Polyphenols are believed to protect against the formation of beta-amyloid, a toxic protein that forms in the brains of Alzheimer's disease patients which may be responsible for some the disease's damaging effects. Earlier research had found that little, if any, polyphenols reached the brain following ingestion; however, these experiments evaluated polyphenol levels following single or sporadic dosing.
Purdue University associate professor of food science Mario Ferruzzi, in collaboration with Giulio Pasinetti, MD of Mount Sinai School of Medicine, administered three different doses of a grape seed polyphenol extract to rats by intragastric gavage. The polyphenols gallic acid, catechin and epicatechin, and their metabolites were found in plasma in dose-dependent levels after one dose of the extract. Plasma levels measured after ten days of continual ingestion doubled in comparison with levels measured after just one polyphenol dose. Importantly, although epicatechin and catechin were not detectable in the brains of the animals after one dose, they reached significant levels following ten days of administration. "This shows that reasonable and chronic consumption of these products may be the way to go, rather than single, high doses, similar to drugs," Dr Ferruzzi explained. "It's like eating an apple a day, not a case of apples over two days every month."
"The most important thing is that when we follow the repetitive administration of this compound, we were able to observe the transfer of the compound to the brain," noted Dr Pasinetti, who is the Aidekman Family Professor in Neurology and director of the Center of Excellence for Novel Approaches to Neurotherapeutics. "This may help us figure out the proper concentration necessary to get these chemicals to the brain."
Dr Ferruzzi observed that their discovery may be relevant to the delivery of other compounds and drugs. "It could become important in terms of side effects," Ferruzzi said. "You could be overdosing because the body is adapting and absorbing or metabolizing these compounds differently over time."
He added that future research will seek to determine the mechanisms that govern the absorption of compounds during chronic consumption.