One of the beneficial compounds found in green tea has a powerful ability to increase the number of "regulatory T cells" that play a key role in immune function and suppression of autoimmune disease, according to new research at the linus pauling Institute at Oregon State University.

It is thought to be one of the underlying mechanisms for the health benefits of green tea, which is already known to help control inflammation, improve immune function and prevent cancer.

"This appears to be a natural, plant-derived compound that can affect the number of regulatory T cells, and in the process improve immune function," said the principal investigator.

"When fully understood, this could provide an easy and safe way to help control autoimmune problems and address various diseases."

There are many types of cells that have different roles in the immune system, which is a delicate balancing act of attacking unwanted invaders without damaging normal cells. In autoimmune diseases, which can range from simple allergies to diabetes or even terminal conditions, this process goes wrong and the body mistakenly attacks itself.

Some cells exist solely to help control that problem and "turn off" the immune system, including regulatory T cells.

In this study, scientists carried out experiments with a compound found in green tea, a polyphenol called epigallocatechin-3-gallate or EGCG, which is believed to be responsible for much of its health benefits and has both anti-inflammatory and anti-cancer characteristics. They found it could cause a higher production of regulatory T cells. Its effects were not as potent as some of those produced by prescription drugs, but it also had few concerns about long-term use or toxicity.

"EGCG may have health benefits through an epigenetic mechanism, meaning we aren't changing the underlying DNA codes, but just influencing what gets expressed, what cells get turned on,"

"And we may be able to do this with a simple, whole-food approach."

In mice, the treatment with EGCG significantly increased the numbers and frequencies of regulatory T cells found in spleen and lymph notes, and in the process helped to control the immune response.

"Epigenetic regulation can be potentially exploited in generating suppressive regulatory T cells for therapeutic purposes, and is of significant clinical importance for the suppression of autoimmune diseases," the researchers said in their study.

All tea plants come from the same plant species, but the way the leaves are processed determines the type of tea it is: green, black and oolong. Green tea is the least processed and thus provides the most antioxidant polyphenols.

Green tea has a bitter, slightly astringent flavor and adding honey, lemon and/or ginger can make it more palatable.

Research Paper Details:

Wong CP, Nguyen LP, Noh SK. Induction of regulatory T cells by green tea polyphenol EGCG. Immunology Letters, 2011.