Tea is the most popular beverage in the world, second only to water. The cup of tea is a British institution; a newly published review of the evidence suggests that the humble cup of tea provides much more than a hot, comforting drink.
Green tea, black tea and oolong tea are all infusions of dried leaves from the Camellia sinensis plant, all of which are rich in a group of flavonoids known as catechins. Flavonoids are a group of water-soluble phytonutrients that give certain plants their colour and are associated with the health benefits of fruit and vegetable consumption.
In cell culture studies, green tea catechins induce cell death in cancer cells while in animal studies, green tea can inhibit tumours in various organs such as the skin, lungs, liver, stomach, mammary glands and colon. In humans evidence suggests that green tea consumption can modestly reduce cholesterol and reduce the risk of developing cancer.
There are several small human studies addressing the use of green tea extract (GTE) capsules for weight loss or weight maintenance in overweight or average weight individuals; green tea is thought to increase thermogenesis (the rate at which calories are burned) but more research is needed. One study showed a decrease in body weight and fat deposits in the liver among mice fed with GTE. Green tea is also especially rich in the non-protein, neurologically active amino acid l-theanine, which may promote relaxation.
One cup of tea contains approximately 50 milligrams of caffeine, depending on the strength and size of cup (as compared to coffee which contains 65 to 175 milligrams of caffeine per cup). It also contains tannins, compounds which can reduce the absorption of non-haem (plant sourced) iron, it is therefore best consumed between meals (about half an hour after a meal is fine). It is also worth knowing that casein, a protein found in milk, may reduce the flavonoid activity of tea.
This summer cool down with a glass of iced tea.
www.nutri.co.uk health news 104
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