Will Green Tea Keep You From Getting Sick?

Green tea is widely praised by health enthusiasts, and for good reason. Both in-vitro studies and clinical trials have supported the notion that green tea can prevent osteoporosis, breast cancer, skin problems, heart disease and digestive problems. While green tea is by no means a panacea or a substitute for a healthy lifestyle, some emerging evidence suggests that it can also enhance overall immunity. Whether it is consumed as a beverage or taken in the form of a supplement, green tea may help to enhance the body's defenses against pathogenic bacteria, fungi and viruses.

Mechansim

• Alkylamines are a fascinating class of compounds found in tea leaves. In addition to the many other nutritious factors found in green tea, these chemicals can help to prevent illness by encouraging the mobilization of natural immune defenses in the bloodstream. Alkylamines are also found in many forms of fungus, virus and bacteria, as well as cancer cells. Immunologists such as Dr. Jack F. Bukowski of Harvard Medical School have suggested that the alkylamines in green tea can "prep" the immune system by teaching it to recognize the compounds in pathogenic invaders.

Study

• Scientists at Harvard University found that the alkylamines in green tea helped to boost immune function during in-vitro clinical trials. To test their theories, immunologists simulated a bacterial infection in test tubes filled with human blood. They found that the blood that was exposed to alkylamines responded much more strongly to the infection--the number, size and strength of immune-defense cells was significantly greater. The researchers suggested that green tea can enhance immune function five-fold, and later confirmed the results of the test with a human clinical trial. It, too, indicated that green tea drinkers have enhanced immunity.

Other Factors

• Aside from alkylamines alone, green tea may offer other nutrients and compounds that support immune health. For instance, green tea is a source of vitamin C, long touted for its immune-boosting properties. The antioxidant effects of green tea also can prevent oxidative stress on the body, which is a risk factor for disease. People who consume green tea regularly are also more likely to be health conscious in general, so its immune-supporting effects may be compounded by the general effects of a healthy, active lifestyle.

Other Alkylamine Sources

• The active disease-preventing compounds of green tea are found in many other plant-based foods as well. All forms of the tea plant (camellia sinensis) contain moderate amounts of alkylamines. White tea, black tea and oolong tea all are good sources of these compounds because they contain L-theanine, an amino acid the body naturally converts into alkylamine. Additionally, alkylamines are found in common foods like apples, mushrooms and wine. Because they are a relatively recent discovery, few studies have fully investigated the long-term effects that alkylamines have on the human body.

Speculation

• The preliminary studies about green tea's effect on immune health have been encouraging. Clinical trials, however, have been far too limited for scientists to draw any concrete conclusions. Green tea probably helps to prevent infectious disease, but evidence is still sparse and inconclusive. Given the numerous health benefits associated with green tea, many nutritionists advise that adults drink it daily. While its efficacy in disease prevention remains essentially unproven, consumers may choose to view immune support as an added "perk" associated with an already-healthy drink.