[This abstract first appeared in: Dementia: the Latest Evidence Newsletter RWHT Volume 1 Issue 7 February 2011].
A concentrated green tea extract after treatment in the laboratory to mimic the effects of normal digestion was found to contain over 30 major compounds, called polyphenols which remain active after being “digested”. The extract was then tested on rat nerve cells to see whether it helped protect against the toxic effects of certain chemicals and a protein linked to Alzheimer’s disease.
The results indicate that green tea metabolites (the contents of the green tea extract) can reduce cell death caused by hydrogen peroxide and beta-amyloid protein in the laboratory. The evidence provides the basis for further studies into flavanols (polyphenols) as a potential way of alleviating some of the effects of Alzheimer’s disease.
Note: These findings do not offer conclusive evidence that green tea combats Alzheimer’s disease or other conditions. This study used animal cells grown in the laboratory and caution is required before applying this research to humans. It is uncertain whether the cell protection seen in isolated rat nerve cells in the laboratory is applicable to human Alzheimer’s disease.
Green Tea and Alzheimer’s Disease. NHS Choices, January 6th 2011.
Okello, EJ. McDougall, GJ. Kumara, S. [et al] (2010). In vitro protective effects of colon-available extract of Camellia sinensis (tea) against hydrogen peroxide and beta-amyloid (Aβ(1–42)) induced cytotoxicity in differentiated PC12 cells. Phytomedicine, December 22nd 2010. [Epub ahead of print].
Also of interest:
Noguchi-Shinohara, M. Yuki, S. Dohmoto, C. [et al] (2014). Consumption of green tea, but not black tea or coffee, is associated with reduced risk of cognitive decline. PLoS One. May 14th 2014; 9(5): e96013.