- Tea Pouches
- Loose Tea
- Iced Tea
- Why Mighty Leaf?
Tea Rallies the Immune System
Adapted from Functional Food Net, April 21, 2003Drinking tea may prime the immune system, placing cells on guard against
possible infection, according to new research. Tea contains alkylamine
antigens, a group of chemicals also present in some bacteria, tumor cells,
parasites, and fungi. Coffee does not have the same effect.
Researchers lead by Jack Bukowski announced their results at the National Academy of Sciences. Bukowski's team examined the effects of the alkylamine antigen on immune system components known as gamma-delta T cells, a critical first line of defense against infection. After briefly exposing cultured human gamma-delta T cells to an alkylamine antigen, the researchers exposed the cells to heat-killed bacteria to simulate an infection. The antigen-exposed cells mounted a robust immune response by multiplying up to 10-fold and secreting disease-fighting chemicals. In contrast, cells not previously exposed to an alkylamine antigen showed no significant response to the simulated infection.
To investigate the response in humans, the scientists asked volunteers to drink either five small cups of black tea or coffee daily for up to four weeks. Green and black teas contain an alkylamine antigen and its precursor, L-theanine, but coffee does not. Two weeks into the study, gamma-delta T cells from tea drinkers showed an enhanced ability to produce disease-fighting chemicals; however, this response was absent in coffee drinkers. These results suggest that drinking tea can promote a strong immune response, in addition to other known healthful benefits.
L-theanine is broken down in the liver to ethylamine, a molecule that primes the response of an immune system element called the gamma-delta T cell.
“We know from other studies that these gamma-delta T cells in the blood are the first line of defense against many types of bacteria, viral, fungal and parasitic infections,” Bukowski said. “They even have some anti-tumor activity.”
"T cells prompt the secretion of interferon, a key part of the body's chemical defense against infection," Bukowski continued, “We know from mouse studies that if you boost this part of the immune system it can protect against infection."
To further test the finding, Bukowski's team asked 11 volunteers drink five cups a day of tea, and 10 others drink coffee. Before the test began, they drew blood samples from all 21 test subjects.
After four weeks, they took more blood from the tea drinkers and then exposed that blood to the bacteria called E-coli. The result was the immune cells in the specimens secreted five times more interferon than did blood cells from the same subjects before the weeks of tea drinking. Blood tests and bacteria challenges showed there was no change in the interferon levels of the coffee drinkers, he said.
Bukowski said it may be possible to further isolate and refine L-theanine from tea and use that as a drug to boost the infection defense of the body.
“This is potentially a very significant finding,” said Penny Kris-Etherton, a nutrition specialist at Penn State University, “We're seeing multiple benefits from tea.” Further research is needed to confirm these initial results, but it is part of a growing body of research showing multiple health benefits from tea.