Research has already shown that green tea may help reduce the risk of flu.
Now, research has found that theanine, a rare protein found in green tea, combined with cystine (a more common protein) may increase the immune response of some elderly patients after flu vaccination.
32 patients in a nursing home received theanine combined with cystine and 33 received placebo orally for 14 days before flu vaccination.
Their blood was tested for antibodies prior to the test period and four weeks after vaccination.
Theanine improved immune response
Results showed that the elderly patients with low hemoglobin or low serum total protein showed a significantly better immune response with antigen-specific immunoglobulin antibody production to influenza type A (H1N1).
The low hemoglobin group showed 63% antibody seroconversion with theanine/cystine compared to 10% with placebo.
The low total protein group showed 71% antibody seroconversion with theanine/cystine compared to 9% with placebo.
There were no other differences detected in this test, but the sample size was small.
This work confirms earlier animal studies showing improved antibody response to flu vaccine with administration of theanine plus cystine (Miyagawa, Co-administration of l-cystine and l-theanine enhances efficacy of influenza vaccination in elderly persons: nutritional status-dependent immunogenicity, Geriatrics and Gerontology International, December 2008).
The elderly are at high risk for influenza infections with complications because of weaker immune systems. Flu vaccines may also be less effective for them when they do not produce strong antibody reactions to the vaccines.
Theanine is found in green tea at cup of tea strength.
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This page last updated by Sharon Jones on December 28, 2012
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