The researchers have found that the amount of polyphenols from grapeseed extract that can reach a rat's brain is as much as 200 percent higher on the 10th consecutive day of feeding as compared to the first.
They point out that many past studies, in which absorption was measured after single or sporadic doses, often found very little of the bioactive polyphenols reaching brain tissues.
However, they add, more chronic exposure appears to improve absorption.
"This shows that reasonable and chronic consumption of these products may be the way to go, rather than single, high doses, similar to drugs. It's like eating an apple a day, not a case of apples over two days every month," said Mario Ferruzzi, a Purdue associate professor of food science, who collaborated on the research with Mount Sinai's Dr. Giulio Pasinetti.
Pasinetti says that discovering how polyphenols are absorbed and distributed to the brain can impact the scientific understanding of the amount of grape products or red wine a person would need to consume to most effectively combat Alzheimer's disease.
"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. This may help us figure out the proper concentration necessary to get these chemicals to the brain," Pasinetti said.
Though the study dealt with polyphenols, Ferruzzi said that it could also be significant for determining proper doses of other compounds or drugs for patients.
"It could become important in terms of side effects. You could be overdosing because the body is adapting and absorbing or metabolising these compounds differently over time," Ferruzzi said.
Ferruzzi said that further studies would focus on the mechanisms that control absorption of compounds during chronic consumption.
A paper detailing the findings has been published in the early online version of the Journal of Alzheimer's Disease.