Green tea may prove helpful in Alzheimer's prevention

• In an article published Sept. 21 in the Journal of Neuroscience, USF researchers report that a component of green tea prevented Alzheimer's-like damage in the brains of mice genetically programmed to develop the neurodegenerative disease process.
• The component, called epigallocatechin-3-gallate (EGCG), is a major antioxidant in green tea and has been widely studied for its reported protection against certain cancers.
• Now the USF team provides the first evidence that EGCG decreases production of the Alzheimer's-related protein, beta-amyloid, which can accumulate abnormally in the brain and lead to nerve damage and memory loss.
• After treating Alzheimer's mice for several months with daily injections of pure EGCG, the researchers observed a dramatic decrease -- as much as 54 percent -- of brain-clogging Alzheimer's plaques.
• "The findings suggest that a concentrated component of green tea can decrease brain beta-amyloid plaque formation," said senior study author Jun Tan, PhD, MD, director of the Neuroimmunology Laboratory at the Silver Child Development Center, USF Department of Psychiatry.
• "If beta-amyloid pathology in this Alzheimer's mouse model is representative of Alzheimer's disease pathology in humans, EGCG dietary supplementation may be effective in preventing and treating the disease."
• Green tea contains many antioxidants, including those known as flavonoids that can protect against free radical damage to the brain.
• However, Dr. Tan and colleagues demonstrated that other flavinoids in green tea actually oppose naturally-occurring EGCG's ability to prevent the harmful build-up of beta-amyloid.
• "This finding suggests that green tea extract selectively concentrating EGCG would be needed to override the counteractive effect of other flavinoids found in green tea," said study co-author Doug Shytle, PhD. "A new generation of dietary supplements containing pure EGCG may lead to the greatest benefit for treating Alzheimer's disease."
• Dr. Tan said humans would likely need 1500 to 1600 mg of EGCG daily to approximate the injection dosage that benefited the Alzheimer's mice.