Green Tea Intake Shows Protective Effect Against Flu

Life Extension Featured Article

August 16, 2011

Green tea intake shows protective effect against flu

Green tea intake shows protective effect against flu

In addition to ensuring optimal intake of vitamins C and D during the upcoming flu season, it may be wise to regularly indulge in a soothing pot of green tea, according to the results of a Japanese study published online on August 10, 2011 in the Journal of Nutrition.

Researchers at the University of Shizuoka and Kikugawa General Hospital conducted two surveys of 2,050 pupils aged 6 to 13 who resided in a tea plantation area of Japan during influenza season from November, 2008 to February, 2009. The responses provided information concerning the frequency and quantity of green tea intake, preventive measures taken against influenza, and the incidence and duration of infections.

During the survey period, 204 cases of flu were confirmed by influenza antigen testing. Among children who reported drinking green tea at least six days per week there was a 40 percent lower risk of being diagnosed with influenza compared to those who consumed tea fewer than three days per week. Subjects who consumed one to two cups per day had a 38 percent lower risk of contracting flu in comparison with those who consumed less than one cup, and a 46 percent lower risk was observed for those who drank three to five cups daily. No greater benefit was determined for drinking more than five cups green tea per day.

"These findings are supported by previous research, which documented the prevention of influenza infection via the antiviral effects of green tea catechins and the enhancement of systemic immunity of theanine," the authors write. "Contrary to the results of green tea consumption, general preventive measures (such as influenza vaccination, hand hygiene, and the use of facemasks) were not associated with the incidence of influenza infection."

"Further clinical studies, including randomized controlled trials, are required to confirm the preventive effects of green tea consumption on influenza infection, including the number of affected days and degree of symptoms, as well as to assess the safety of green tea consumption by children," they conclude.

Printer Friendly Save as PDF Email this Page View Archive Subscribe Today
Health Concern


Influenza (commonly known as the flu) is one of the most feared and deadly infectious diseases (Dolin R 2004; Hilleman MR 2002; Nicholson KG et al 2003).

Even when the flu does not reach pandemic proportions, it is the source of misery, illness, and death every flu season, which runs roughly through the fall and early winter months in North America. Since the early 1970s, researchers estimate that influenza has caused more than 40,000 deaths in the United States every year (Dushoff J et al 2006). It is estimated that flu outbreaks cost about $12 billion annually in the United States (Kasper DL et al 2004).

Green tea has been shown to inhibit bacteria and viruses and stimulate the immune system (Imanishi N et al 2002). Black tea and extracted components, such as catechin and saponins (Hayashi K et al 2000), inhibit influenza virus growth, infectivity, and symptoms (Iwata M et al 1997b; Iwata M et al 1997a). In a cell culture study, the active ingredients in green tea were found to be powerful inhibitors of all varieties of influenza virus (Song JM et al 2005).

The following doses are higher than the usual recommended doses for these supplements. These higher levels should not be taken constantly, or as a general prophylaxis. They should be taken to enhance seasonal support. This program should be followed for only a few days. At the first sign of flu symptoms, consider taking:

  • Cimetidine—800 to 1000 mg/day
  • Pure Gar brand garlic—9000 mg once or twice a day
  • Kyolic aged garlic extract—3600 mg/day
  • DHEA—200 to 400 mg in the morning
  • Lactoferrin—1200 mg/day
  • Zinc—Two 24 mg lozenges every 2 hours while awake. This is a very high dosage of zinc and is toxic if taken for long periods. Only take this much zinc for a few days.
  • Melatonin—10 to 50 mg at bedtime
  • Vitamin C—6000 mg/day (1000 mg every hour for the first 6 hours), then 3000 mg/day (1000 mg several hours apart).
  • Vitamin E—400 international units (IU) daily
  • Green tea—725 mg/day. A decaffeinated form is available for people who are sensitive to caffeine.
  • Selenium—200 micrograms (mcg) daily
  • Elderberry extract—Take lozenges as needed.
Featured Products

Solarshield® Sunglasses

add to cart

Solarshields® block solar radiation in three ways:

  1. A unique top shield blocks direct overhead sun rays (like a brimmed hat).
  2. Wide side shields screen out peripheral sun rays while permitting protected side vision.
  3. A patented polycarbonate lens filters out 100% of UV sunlight.

Solarshields® provide more protection than conventional sunglasses and can be worn over most prescription eyeglasses. Solarshields are rated as 100% UV protected.

Sustained Release Venotone

add to cart

Horse chestnut extract supports a healthy fluid balance plus antioxidant, venotonic (helpful to veins), and vasoprotective (protective of vessels or ducts) actions. The key active ingredient in horse chestnut is a substance called escin.

Venotone is an extract of horse chestnut, which has been standardized and concentrated to ensure the highest quality, consistency and biological activity. Sustained release provides continuous activity while minimizing the potential for gastric irritation.

News Archive

Life Extension Update

What's Hot

Life Extension® Magazine

Natural Relief 1222™ and Natural Relief 1222™ logo are trademarks of NR1222 LLC. All rights reserved. FernBlock® is a registered trademark of Industrial Farmaceutica Cantabria, S.A. Patent pending Sendara® is a registered trademark of Nutragenesis, LLC.

If you have questions or comments concerning this issue or past issues of Life Extension Update, send them to or call 1-800-678-8989.
Sign up for Life Extension Update

For Customer Service inquiries, please email or call 1 800 678 8989.

For copyright permission, please refer to Life Extension copyright policy.