1. Tea can boost your immune system: Green tea boosts the number of "regulatory T cells" in the body, which are important for the immune system, according to research from the Linus Pauling Institute at Oregon State University.
"When fully understood, this could provide an easy and safe way to help control autoimmune problems and address various diseases," study researcher Emily Ho, an associate professor at the university says. The research, published in the journal Immunology Letters, specifically focused on the green tea compound EGCG, which is a kind of polyphenol. Researchers believe that the compound may work via epigenetics—by influencing expression of genes—rather than "changing the underlying DNA codes," Ho said in a statement.
2. Tea may lower your risk of heart disease: A review in the European Journal of Clinical Nutrition showed that drinking three or more cups of tea per day is linked with a lower risk of coronary heart disease, potentially because of the amount of antioxidants tea contains. The University of Maryland Medical Center reports that green tea and black tea have atherosclerosis-preventing effects, though the FDA has yet to allow teamakers to claim that green tea can affect heart disease risk.
3. Tea could shrink tumors: Scottish researchers found that applying a compound in green tea called epigallocatechin gallate to tumors shrinks them in size.
"When we used our method, the green tea extract reduced the size of many of the tumors every day, in some cases removing them altogether," study researcher Dr. Christine Dufes, senior lecturer at the Strathclyde Institute of Pharmacy and Biomedical Sciences, said in a statement. "By contrast, the extract had no effect at all when it was delivered by other means, as every one of those tumors continued to grow."
4. It can boost your cognitive function as you age: Drinking green tea could help you function better with basic tasks such as bathing and dressing yourself as you get older, according to a study in the American Journal of Clinical Nutrition. The research, which included 14,000 adults ages 65 and older over a three-year period, showed that the ones who drank the most green tea had the best functioning in old age compared with those who drank the least.
"Green tea consumption is significantly associated with a lower risk of incident functional disability, even after adjustment for possible confounding factors," the study researchers concluded.
5. It may lower blood pressure: Drinking black tea could slightly decrease blood pressure, according to a study in the Archives of Internal Medicine. Reuters reported that participants drank either black tea, or a non-tea beverage that had similar caffeine levels and taste, for six months, thrice daily. The researchers found that those assigned to drink the black tea had a slight decrease in blood pressure, though not enough to bring someone with hypertension back into a safe zone, according to Reuters.