As we hurtle toward the end of summer, back-to-school sales are ramping up, college dorms are filling up . . . and flu season is next up.

So the big question—does tea help prevent colds and flu???

We know that drinking liquids in general helps. As does gargling.

But it doesn’t look like gargling tea specifically makes much of a difference. Although early studies (e.g., Yamada 2006) were encouraging, in February researcher Ide and colleagues (2017) said that “green tea gargling may slightly reduce influenza compared with water gargling” but additional studies are needed. . . .

Of Mice and Tea

But this month, a more promising study—involving mice and, indirectly, tea—was published in Science.

Okay, the subjects were mice, and they weren’t exactly tea drinkers, so results are preliminary. Yet the results are exciting!

Instead of looking to prevent flu, this study probed the body’s response to flu. Therefore, all the study mice were given the flu.

The scientists found that some mice suffered lung damage from the flu whereas other mice had no damage. The difference between the mice?

The ones who were shielded from lung damage had been given a specific metabolite, or DAT (desaminotyrosine).

And Flavonoids, Microbes, and Metabolites, the Short Version

The story is:

• We all have microbes in our guts.
• Some of these microbes break down or metabolize flavonoids, which are compounds found in plants (including tea leaves).
• Flavonoids are good because they have “anti-inflammatory, antioxidant, vasodilatory, anticancerigenic, and antibacterial properties” (Schoefer 2003).
• One of these microbes, Clostridium orbiscindens, breaks down certain flavonoids and makes a metabolite that helps with interferon signals.
• An interferon is a protein that is released when a virus (like the flu virus) is present; it helps the immune system, inhibiting the virus from multiplying.
• That metabolite is, you guessed it, DAT.

The Upshot:

So all the mice had the flu virus. But those that had been treated with DAT experienced less flu-inflicted lung damage (such as pneumonia).

In other words, if the mice already had certain flavonoids—and the right microbes—in their guts, the byproducts from those microbes breaking down those flavonoids served to protect the mice from damage from the flu.

Presumably, then, the same would hold for people.

Next up:

Because we have lots of microbes in our guts, there are undoubtedly others that use flavonoids and, in the process, assist our immune systems. These need to be identified and studied. Also, how can we boost those beneficial microbes in people who have inadequate levels?

The Practical Take-away

So no, this study did not promise that drinking tea would prevent flu. It did, however, suggest that plant flavonoids just might mitigate the effects of flu!

And according to EurekAlert (2017),

the researchers said it might not be a bad idea to drink black tea and eat foods rich in flavonoids before the next flu season begins.

So, put on the kettle!

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Sources:
–Ide, K. Y. Kawasaki, M. Akutagawa, and H. Yamada. “Effects of green tea gargling on the prevention of influenza infection: an analysis using Bayesian approaches,” J Altern Complement Med 2:116–20. February 23, 2017.
–Schoefer, L., R. Mohan, A. Schwiertz, A. Braune, and M. Blaut. “Anaerobic degradation of flavonoids by Clostridium orbiscindens,” Appl Environ Microbiol 69(10):5849–54. October 2003.
–Washington University School of Medicine, “Natural compound coupled with specific gut microbes may prevent severe flu,” EurekAlert AAAS, public release August 3, 2017.
–Yamada, H., N. Takuma, T. Daimon, and Y. Hara. “Gargling with tea catechin extracts for the prevention of influenza infection in elderly nursing home residents: a prospective clinical study,” J Altern Complement Med 7:669–72. September 12, 2006.
NOTE: Tea pictured is Lapsang Souchong from TeaHaus

Filed under: Health & Science Tagged: health benefits