Of all the beverages consumed today, tea is undoubtedly one of the oldest, most widely known, and most widely consumed, and also gives a lot of health benefits. Consumption was introduced to the world by traders and travelers. The method by which tea is processed determines whether green, black, or oolong is produced. Green tea is made by steaming fresh leaves at high temperatures, followed by a sequence of drying and rolling steps, resulting in tea that is for the most part the same chemical composition as the fresh leaves that bring the best health benefits of green tea. Black tea is fermented. The extent of the fermentation period determines the chemical composition of the tea; hence, the chemical composition of most black teas differs. Oolong is produced by solar withering of tea leaves followed by partial fermentation.
Tea leaves include several ingredients, some of which are believed to act as medicinal compounds. A feeling of relaxation can be induced by daily tea consumption. A part of this feeling may be mediated by either EGCG, L-theanine, or both. Tea components may be beneficial in a stressful society, and may have medicinal benefits for several mental diseases.
Tea leaves are also rich in phytochemicals, antioxidants, and caffeine, among a myriad of other chemicals. The amount of caffeine in a serving of tea is usually less than half the caffeine in a serving of coffee, but actual caffeine content can vary widely depending on the specific blend of tea and the brew strength.
Most health benefits of green tea include:
Lowers risk of cardiovascular disease by:
• Reducing inflammation
• Decreasing total cholesterol
• Decreasing LDL-cholesterol
• Protecting against blood clot formation
• Decreasing blood pressure
Decreases risk of cancer by:
• Inhibiting carcinogenesis
• Suppressing formation of carcinogenic substances
• Increasing the effectiveness of a number of chemotherapeutic agents
Protects against neurodegenerative diseases by:
• Decreasing plaque formation associated with Alzheimer’s disease
• Raising dopamine levels to ward off Parkinson’s disease
• Protecting against deterioration of brain function
The health benefits of green tea appear to be dose dependent, meaning that drinking more tea provides the greatest effect.