Ever since 2737 B.C., when Chinese legend says leaves from an overhangingCamellia sinensisplant fell into Emperor Shen Nung’s cup of boiling water, tea has been recognized by cultures around the world for its capacity to soothe, restore and refresh.
Next to water, tea is the most common beverage choice throughout the world. Whether, it’s black, green or oolong tea, tea comes from the same plant, Camellia sinensis. Differences in colour and flavour depend on processing. Herbal teas however, are made from roots, barks, leaves, seeds and flowers. For example chamomile made from flowers; and Rooibos tea, actually not a true tea, but a herb tisane or infusion made from dried Rooibos (Aspalathus linearis) leaves.
Black tea is made by exposing the leaves to air. The natural biochemical process colours the leaves a deep red-brown colour and imparts a unique, rich flavour.
Many flavoured specialty teas start with black tea. To make green tea, the leaves are not processed as much; instead they are just heated or steamed quickly to keep their green colour and delicate flavour. Oolong tea is an in-between tea, between black and green tea.
Green tea has been a substantial component of many Asian societies’ diets for centuries. It contains polyphenols and catechin flavanols which make up about 30% of the dry weight and have antioxidant properties – credited with possible health benefits of drinking green tea.
Green tea also contains caffeine, ranging from 20 – 30 mg/cup of prepared tea. These compounds vary depending on the tea’s variety, age, processing and storage. The content in a cup of brewed tea will also vary depending on brewing time and water temperature. Longer brewing times and hotter brewing temperatures have been shown to result in teas with a greater catechin and caffeine content.
Tea and Heart Health
The strongest evidence is on the side of heart health, attributed to the antioxidants in tea. Flavonoids in tea have been found to prevent oxidation of LDL, or “bad” cholesterol, reduce blood clotting and improve widening of blood vessels in the heart.
Tea is the only simple pleasure left to us.- Oscar Wilde
Can Tea Prevent Chronic Diseases?
Support for tea’s cancer and diabetes prevention benefits is less compelling. It has been suggested that antioxidant polyphenol compounds — particularly catechins — in tea may play a role in disease prevention. However, evidence so far is extremely limited or conflicting.
Tea and Weight Loss
Evidence supporting tea as a weight-loss aid is based mainly on studies that used tea extracts. These results may not be directly applicable to brewed tea consumed in normal amounts.
Tea and Hydration
Studies found no negative effects on hydration with intakes of up to 400 milligrams of caffeine per day (the amount in about 8 cups of the strongest brewed tea).
|How does your daily fix stack up?||Caffeine (mg) per cup (240 ml)|
|Green||20 – 30|
|Leaf or bag||50|
- Tea is grown in about 30 countries around the world.
- Tea is the second most widely consumed beverage worldwide, after water .
- With a per capita worldwide consumption of approximately 0.12 litres per year.
- Unsweetened tea is calorie-free.
- Drinking tea adds to your fluid intake to help you stay hydrated.
- Taking a break with a soothing hot drink can help you relax and reduce stress.
- Green tea contains polyphenols and catechin flavanols which have antioxidant properties credited with possible health benefits of green tea consumption.
The Bottom Line
Are there health benefits to drinking green tea? Maybe…There is much research underway looking at whether green tea can lower your risk of developing certain chronic diseases. Some studies show that tea does have health benefits, while other studies show that tea has no impact on human health. What we do know is that green tea as a beverage can be included as part of a healthy diet for most adults and that much more research is needed before we can make any specific recommendations about green tea for chronic disease prevention.
Written by: Cheryl Meyer