benefits of tea
TEA... THE HEALTHIEST BEVERAGE ON EARTH
People have been exploring tea's health benefits for 5,000 years. Whether we are seeking mental alertness, protection against disease, or renewal of the spirit, we enjoy tea for many reasons.
Research on tea and its health effects is underway in academic institutions and medical settings all over the world and many exciting leads have been uncovered. As more studies begin to test findings on human subjects we gain valuable information about how tea can help us in our own lives.
None of the following information should be interpreted as or substituted for medical advice. It is simply a presentation of some of the promising findings published in recent years.
The Antioxidant Story
Each day, we may be exposed to harmful influences -- foods high in fat and sugar, chemicals in the environment, cigarette smoke, and more. In response, our bodies produce unstable molecules called oxidants or "free radicals" that can damage healthy cells. The result can be chronic illnesses, immune system damage, organ disease, and other health problems. Antioxidants found in foods like fruits, vegetables, and tea, can help to limit the effects of free radicals. The antioxidants combine with free radicals so they can no longer harm other cells. In this way, it is believed that antioxidants may reduce the occurrence and size of some kinds of tumors and inhibit their growth.
You will see many terms associated with antioxidants and tea that might seem confusing at first. They are all closely linked.
- Antioxidants are molecules that slow or stop oxidants.
- Polyphenols found in tea have strong antioxidant qualities.
- Flavonoids are a type of polyphenol found in tea.
- Catechins are a component of flavonoids. There are four types of catechins in tea. EGCG (epigallocatechin gallate) is the one discussed most frequently with regards to tea's health benefits.
Some of the benefits to heart health that have been suggested by early studies include lowering LDL cholesterol (1) and improving the ability of blood vessel lining to expand when blood flow increases (2). Some believe that tea might also help lower blood pressure.
Antioxidants may help to protect Immune System (3) the L-theanine, an amino acid present in tea, may "prime" the immune system to help it fight infection, bacteria, viruses, and fungi. (4) In addition, tea is rich in vitamins and minerals including B1, B2, B6, C, folic acid, magnesium, potassium, and zinc.
Tea's amino acids may also help you gain a calmer, but more alert, mental state. The effect can last for 3 - 4 hours. (5)
Early research suggests that some components of tea might help to reduce cancer risk. This is one of the most active areas of research currently.
Tea contains a natural fluoride, encouraging healthy tooth enamel, (6) and the flavonoids in tea may slow the formation of plaque by bacteria in the mouth. (7)
Tea has no calories and helps to hydrate the body. Substituting unsweetened tea for sugary drinks like soda can be a useful tool in maintaining a healthy weight. It is also thought that tea can help to boost metabolism. (4) One should not, however, believe claims that "Wulong" tea is "weight-loss tea." "Wulong" is simply another word for "oolong" and it has not shown any more, or less, impact on weight loss.
A study in the American Journal of Clinical Nutrition found that older women who were tea drinkers had higher bone mineral density (BMD) than non-tea drinkers. (8)
1 Davies MJ, Judd JT, Baer DJ, Clevidence BA, Paul DR, Edwards AJ, Wiseman SA, Muesing RA, Chen SC. Black tea consumption reduces total and LDL cholesterol in mildly hypercholesterolemic adults. J Nutr. 2003 Oct;133(10):3298S-3302S
2 Duffy SJ, Keaney JF Jr, Holbrook M, Gokce N, Swerdloff PL, Frei B, Vita JA. Short- and long-term black tea consumption reverses endothelial dysfunction in patients with coronary artery disease. Circulation 2001;104:151-6.
3 Kamath AB, Wang L, Das H, Li L, Reinhold VN, Bukowski JF. 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 May 13;100(10):6009-14.
4 Murase T, Haramizu S, Shimotoyodome A, Tokimitsu I. Reduction of diet-induced obesity by a combination of tea-catechin intake and regular swimming.Â Int J Obesity 2005 Oct:1-8.
5 Foxe, J. Investigating the Role of Tea in Human Cognition: Theanine and Caffeine Alter the Neurophysiology of Attention. International Scientific Symposium on Tea & Human Health. 2007 Sept 18.
6 Yu, H., Oho, T., Xu, L. X. Effects of several tea components on acid resistance of human tooth enamel. J Dent 1995;13:101-105.
7 Sarkar, S., Sett, P., Chowdhury, T., and Ganguly, D.K. Effect of black tea on teeth. J Indian Soc Pedod Prev Dent 2000;18:139-140.
8 Hegarty VM, May HM, Khaw K-T. Tea drinking and bone mineral density in older women. Am J Clin Nutr 2000;71:1003-7.
9 University of Michigan Health System Healthwise Knowledgebase
11 National Center for Complementary and Alternative Medicine, National Institutes of Health
12 ORAC of Selected Foods, USDA 2007 and Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University