Recent studies, though they differ in technique, focus on the effect on the brain of polyphenol compounds in green tea. Though the studies used green tea extracts, notably a polyphenol compound called EGCG, experts assure that similar benefits can be gained by sipping tea.
British scientists designed a test to see if green-tea extracts could block the formation of the amyloid plaques associated with Alzheimer’s disease and created ‘balls” of amyloid proteins in the lab, similar to the sticky aggregates that attach to nerve cells in the brains of Alzheimer’s patients.
The researchers then added green tea (EGCG) and red wine (resveratrol) extracts to the amyloid balls. Both extracts distorted the shape of the balls in a way that prevented them from binding to nerve cells and disrupting their functions.
In explanation, the team compared the amyloid balls’ precise attachment to nerve cells to “the way a baseball fits snugly into its glove.” After the addition of the two extracts, the shape of the balls were altered so the toxic proteins no longer ‘fit.”
A multidisciplinary research team of University of Michigan scientists investigating the structural effects of EGCG on amyloid plaques validated these positive findings.
They found that EGCG not only prevented the formation of amyloid aggregates, it also broke down existing aggregates in proteins that contained metals—copper, iron and zinc—metals associated with Alzheimer’s disease.
Sources: Tufts University Health & Nutrition Letter, June 2013 British study published in Biological Chemistry, partially funded by Alzheimer’s Research UK U of Michigan study published in Proceedings of the National Academy of Science