What’s the most widely consumed beverage in the world, after water? The answer is tea, which is consumed by about 3 billion people worldwide, reports the Food and Agriculture Organization (FAO).
This hugely popular beverage has been around for centuries and plays a key role in many Asian cultures.
The main health-promoting substances in tea, produced from the Camellia sinensis plant, are known as polyphenols, which are antioxidants that help protect cells from damage. All types of tea have polyphenols, particularly catechins and epicatechins, but the amount they contain varies depending on the way they are processed.
Green tea, which is made with steamed tea leaves and is minimally processed, has higher amounts of polyphenols, including high concentrations of the catechin EGCG. Black tea, which is oxidised and then dried, has lower amounts of polyphenols.
Factors such as the age of the tea and how it is stored, brewed and served also have an impact on the levels of polyphenols. More polyphenols are released with longer steeping times, although three minutes is considered optimal. Instant and bottled teas have lower levels of polyphenols.
However, because of the caffeine content of tea – an average cup of tea contains 50 mg of caffeine – it is important to drink it in moderation. “In order to not adversely affect your health, it is advisable to limit your tea intake to no more than 3 to 4 cups per day,” advises Singapore’s Ministry of Health. “Choose teas that are unsweetened or sweetened with less sugar.”
The caffeine content of tea is less than that of coffee, which has 100 mg of caffeine in a cup.
4 health benefits of tea
- Cardiovascular health: Some studies have found that individuals who consume green or black tea have a reduced risk of cardiovascular disease, especially, stroke. Tea may also improve blood vessel functioning, reduce inflammation, blood pressure and bad LDL cholesterol, and inhibit blood clotting.
- Diabetes: A 2012 study found that high consumption of black tea was strongly associated with a reduced diabetes risk, while a 2013 Chinese meta-analysis of clinical trials suggested that green tea helped reduce blood sugar.
- Cancer: Green tea polyphenols have been shown to inhibit a wide variety of cancers, including bladder, breast, lung, stomach, pancreatic, and colorectal cancers.
- Bone health: Lab studies show that tea polyphenols have beneficial effects on factors affecting bone mass and bone strength and may help protect against osteoporosis.