Green tea, prepared from the unfermented leaves of the Camellia sinensis plant, offers many health benefits and is high in antioxidants. The potent antioxidant effects of green tea come primarily from substances in green tea called polyphenols, which also provide the moderately bitter flavor. Epigallocatechin gallate, or EGCG, is the most active polyphenol in green tea. Some of the health benefits of green tea relate specifically to disease processes associated with aging. As with starting any new treatment or nutritional program, consult your doctor first.
Alzheimer's Disease
According to a study at King's College London, the epicatechin in green tea, as well as in red wine, cocoa and many fruits and vegetables, can slow the brain cell damage associated with Alzheimer's disease. The disease is believed to result from amyloid plaques, which are a buildup of sticky proteins in the brain. Epicatechin was found to protect brain cells from damage by preventing the formation of these plaques.
Arthritis
The antioxidants in green tea may prevent arthritis due to their ability to fight inflammation. Research conducted at Case Western Reserve University suggests that green tea can delay the onset and decrease the severity of rheumatoid arthritis. A study conducted at the University of Sheffield Medical School found that the consumption of green tea may protect against arthritis, slow cartilage breakdown in the joints and reduce inflammation in patients with arthritis.
Depression
A study published in the "American Journal of Clinical Nutrition" examined the effect that green tea consumption had on symptoms of depression in elderly Japanese subjects. A self-administered questionnaire was used to determine the amount of green tea consumed, while the Geriatric Depression Scale was used to evaluate symptoms of depression. According to the study, symptoms of depression occurred less often when green tea was consumed more frequently.
Osteoporosis
Research suggests that green tea may be able to help in the prevention and treatment of osteoporosis. Scientists in Hong Kong exposed bone-forming cells, or osteoblasts, to three components in green tea -- epigallocatechin, gallocatechin and gallocatechin gallate. They found the epigallocatechin in green tea can promote bone growth, increase bone mineralization levels and block osteoclasts, which break down and weaken bones.
Prostate Cancer
Researchers at Louisiana State University Health Sciences Center conducted a study on 26 men, ages 41 to 68, with prostate cancer. The men drank the equivalent of 12 cups of green tea a day for an average of 34 days. In all of the men, the biomarkers for prostate cancer were reduced, some by as much as one-third. Another study in Italy evaluated men with high-grade prostate intraepithelial neoplasia, a condition that can lead to prostate cancer. This study found that the consumption of green tea lowered the risk of developing prostate cancer.
Longevity
Free radicals -- damaging particles that occur both naturally in the body and from exposure to environmental toxins -- can contribute to the aging process and also to diseases such as cancer and heart disease. Antioxidants, such as the polyphenols in green tea, may reduce or even prevent some of the damage caused by free radicals. One study in Japan evaluated the relationships between green tea consumption and mortality from all causes, cancer and cardiovascular disease in people aged 65 to 84. Higher green tea consumption was found to be associated with decreased mortality from all causes and coronary vascular disease. The study also found that green tea may offer protection against colorectal cancer.
References
- The Telegraph: Plant Chemicals Keep Alzheimer's at Bay, Study Finds
- PubMed.gov: Prevention of collagen-induced arthritis in mice by a polyphenolic fraction from green tea
- The Journal of Nutrition: Catechins from Green Tea (Camellia sinensis) Inhibit Bovine and Human Cartilage Proteoglycan and Type II Collagen Degradation In Vitro
- The American Journal of Clinical Nutrition: Green Tea Consumption Is Associated With Depressive Symptoms in the Elderly
- Journal of Agricultural and Food Chemistry: Effects of Tea Catechins, Epigallocatechin, Gallocatechin, and Gallocatechin Gallate on Bone Metabolism
- Cancer Prevention Research: Tea Polyphenols Decrease Serum Levels of Prostate-Specific Antigen, Hepatocyte Growth Factor, and Vascular Endothelial Growth Factor in Prostate Cancer Patients and Inhibit Production of Hepatocyte Growth Factor and Vascular Endothelial Growth Factor In vitro
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