Immune Health

Is green tea an immune booster?

Based on recent clinical findings, immune booster may be another health benefit to add to green tea’s extensive research portfolio. Although green tea is most commonly recognized as an important antioxidant, researchers have begun to focus on its potential to influence immune health. Read on to learn more about green tea and immunity.

Brewing up natural immune defense

Interestingly, emerging scientific research suggests that green tea and several of its components may help the body get ready to fight battle with environmental culprits. Initial research experiments in test tube and animal studies found that green tea may function in several ways to influence immunity. Scientists reported that green tea or its components may: 1) stimulate the production of various immune cells; 2) fend off bacteria and viruses; and 3) promote the production of various substances that help support immune function.1-6

Further experimental research uncovered that L-theanine, an amino acid component of green tea, is broken down in the body to another compound that stimulates the production of important immune cells.7,8 What’s more, the natural immune defense of immune cells from regular tea drinkers (ie, 6 small cups daily) was found to be 5 times faster than those of coffee drinkers. Because coffee drinking had no effect on the immune cells, researchers propose that tea’s unique chemical components are responsible for the potential immune cell boost that was recorded.8

Can supplements offer the same benefit as brewed tea?

While the findings thus far are encouraging, additional research evaluating the potential immune benefit of green tea supplements in humans is needed to determine what dosage may support immunity. In the meantime, the first clue to a potential benefit from green tea supplements comes from a recent well-controlled study from the University of Florida. Researchers examined a proprietary supplement containing L-theanine, green tea extract (standardized to contain 50% polyphenols and 45% EGCG) and rooibos tea extract. Compared to individuals taking a placebo (inactive supplement), the green tea supplement group faired significantly better during the cold weather season from January to May.9 In addition, researchers recorded a significant 28% increase in a specific type of immune cell from the green tea group compared to the same immune cells analyzed from subjects taking placebo. The immune cells from the green tea group also secreted 26% more interferon gamma, a substance that supports a healthy immune response.

Natrol offers the following products that you can use to boost your intake of L-theanine, polyphenols and EGCG, the active constituents of green tea that are being studied for immune health benefits.

  • Natrol® Green Tea 500 mg: A guaranteed potency extract that provides 50% polyphenols and 25% catechins, including EGCG. Take 1-2 capsules daily.
  • Laci Le Beau® Green Tea: All natural green tea leaf is a healthy beverage choice each day. Drink one or more cups daily.
  • Natrol® L-theanine: Contains 150 mg of L-theanine in two tablets and has been studied for its relaxing qualities. Take 2 tablets daily.

References

  1. Stoner GD, Mukhtar H. Polyphenols as cancer chemopreventive agents. J Cell Biochem. 1995;22:169-180.
  2. Hamilton-Miller JM. Antimicrobial properties of tea (Camellia sinensis L.). Antimicrob Agents Chemother. 1995;39:2375-2377.
  3. Zvetkova E, Wirleitner B, Tram NT, et al. Aqueous extracts of Crinum latifolium (L.) and Camellia sinensis show immunomodulatory properties in human peripheral blood mononuclear cells. Int Immunopharmacol. 2001;1:2143-2150.
  4. Zhu M, Gong Y, Yang Z, et al. Green tea and its major components ameliorate immune dysfunction in mice bearing Lewis lung carcinoma and treated with the carcinogen NNK. Nutr Cancer. 1999;35:64-72.
  5. Cheng S, Ding L, Zhen Y, et al. Progress in studies on the antimutagenicity and anticarcinogenicity of green tea epicatechins. Chin Med Sci J. 1991;6:233-238.
  6. Song JM, Lee KH, Seong BL. Antiviral effect of catechins in green tea on influenza virus.
    Antiviral Res. 2005;68:66-74.
  7. Bukowski JF, Morita CT, Brenner MB. Human gd T cells recognize alkylamines derived from microbes, edible plants, and tea: implications for innate immunity. Immunity. 1999;11:57-65.
  8. Kamath AB, Wang L, Das H, et al. Antigens in tea-beverage prime human Vgamma 2Vdelta 2 T cells in vitro and in vivo for memory and nonmemory antibacterial cytokine responses. Proc Natl Acad Sci USA. 2003;100:6009-6014.
  9. Rowe CA, Nantz MP, Bukowski JF, et al. Specific formulation of Camellia sinensis prevents cold and flu symptoms and enhances T cell function: A randomized, double-blind, placebo-controlled study. J Am Coll Nutr. 2007;26:445-452.