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Health Benefits of Green Tea

Jun 14, 2011 | By Sandra Ketcham
Health Benefits of Green Tea
Photo Credit tea image by Horticulture from Fotolia.com

Green tea is produced from the dried and steamed leaves of Camellia sinensis, and medicinal use of the tea dates back about 5,000 years to China. The health benefits of green tea are likely due to a substance called epigallocatechin-3-gallate, or EGCG, and this substance accounts for about 40 percent of total polyphenol content of the tea, according to Memorial Sloan-Kettering Cancer Center. Consult your doctor before beginning supplementation with green tea or any other product.

Cardiovascular Disease

Regular intake of green tea may protect against coronary artery disease, atherosclerosis, high triglycerides and hypertension. The tea may also offer benefits as a blood thinner, reducing stroke risk and brain damage, and may help speed recovery from heart attack. Green tea may also be useful as a treatment for high LDL cholesterol. In fact, a study published in the 2003 issue of "Archives of Internal Medicine" showed that green tea enriched with theaflavin effectively reduced LDL levels when used in conjunction with a low-saturated fat diet. The National Institutes of Health says that while some evidence supports that green tea may reduce the risk of heart attack and atherosclerosis, more research is needed for a conclusion. Some human studies have shown an increase in hypertension following consumption of green tea, possibly due to the tea's caffeine content and stimulant effects.

Cancer

Green tea may protect against some cancers because of its high antioxidant content, and certain compounds in the tea may prevent the formation of new blood vessels that feed tumors, states the American Cancer Society. But study results are mixed and more information is needed to determine any benefits the tea offers. Memorial Sloan-Kettering Cancer Center states that the EGCG in green tea prevents vascular growth, leads to apoptosis in leukemic cells and may also inhibit enzymes involved in cell replication and DNA synthesis. These benefits may prevent or slow the development and spread of some cancers, including prostate, pancreatic, lung, colorectal, esophageal, ovarian, breast and bladder cancers. The tea may also help prevent and slow the growth of skin cancers, according to the University of Maryland Medical Center, because of the anticancer and anti-inflammatory properties of EGCG and other polyphenols in the tea.

Diabetes

Green tea has a long history of use as a natural method of controlling blood sugar levels, and animals studies show it may help prevent the development of type 1 diabetes and slow its progression after development, according to the UMMC. Human studies are lacking, but the results of a study published in the August 2004 issue of "BMC Pharmacology" showed that humans who consumed green tea before taking oral glucose tolerance tests displayed an increased ability to properly utilize blood sugar.

Periodontal Disease

Green tea may help prevent gum disease and cavities because it acts as an antibacterial, and green tea leaves contain fluoride, a substance known to prevent cavities. The fluoride concentrations in green tea leaves are similar to those recommended for water supplies.

Osteoporosis and Bone Loss

World's Healthiest Foods says green tea may prevent and treat bone loss and osteoporosis as well as the traditional therapy of calcium and exercise. Additionally, regular consumption of green tea by elderly women resulted in the preservation of hip structure, a site often severely affected by osteoporosis, according to the 2007 issue of the "American Journal of Clinical Nutrition."

Weight Loss

The combination of caffeine and catechins in green tea may boost metabolism and burn fat, according to World's Healthiest Foods. This benefit is specific to visceral fat, the type that accumulates in the tissues of the abdominal cavity and around the intestines. Deposits of visceral fat are associated with metabolic syndrome and type 2 diabetes. Animal studies show high doses of green tea stimulate the use of fatty acids by muscle and liver cells, thereby reducing the rate of glycogen use and allowing longer periods of exercise before fatigue. The NIH cautions that while there is some evidence green tea may promote weight loss and control, study results are mixed and more information is needed.

Diseases of Cognition

World's Healthiest Foods says green tea's catechins offer a variety of neuroprotective benefits, including the scavenging of free radicals, the regulation of mitochondrial function, iron chelation and a reduction in damage to brain cells. This may be of benefit to those at risk for or suffering from dementia, Alzheimer's disease, Parkinson's disease or a general decline in mental sharpness. But results are inconclusive, and it is not clear if green tea is beneficial for memory and cognition, explains the NIH, although the tea contains caffeine and may stimulate neuroprocesses through that mechanism.

Viral and Bacterial Infections

Research is ongoing into the antiviral and antibacterial benefits of green tea, and an extract of the tea is currently approved for use an external topical treatment for genital warts caused by the human papillomavirus, according to the NIH. Green tea may also decrease viral loads in HTLV-1 carriers and help prevent flu and cold symptoms. A study published in the November 2005 issue of "Antiviral Research" concluded that compounds in green tea inhibit the replication of the influenza virus and may speed recovery from the flu.

References

Article reviewed by Alan Craig Last updated on: Jun 14, 2011

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