Tea contains catechins, a type of antioxidant known to have anti-inflammatory and neuroprotective properties. It helps regulate food intake, and has an affinity for cannabinoid receptors, which may suppress pain and nausea, and provide calming effects. Tea also contains the amino acid, L-theanine  which modulates caffeine’s psychoactive effect and contributes to the taste of tea. Tea contains small amounts of theobromine and theophylline as well. Theobromine is used as a vasodilator, diuretic & heart stimulant while theophylline is used in drug therapy for respiratory diseases.

Tea contains flavonoids which are a group of phytochemicals present in most plant products that are responsible for health effects such as anti-oxidative and anticarcinogenic functions. However, the content of flavonoids may vary dramatically among different tea products.

Teas can generally be divided into categories based on their level of oxidation during processing. There are at least six different types of tea: white, yellow, green, oolong (or wulong), black (called red tea in China), and post fermented tea (or black tea for the Chinese) of which green is the least oxidized and black is the most oxidized.  The most commonly found teas on the market are white, green, oolong, and black. Some varieties, such as green, traditional oolong tea and pu-erh tea, a post-fermented tea, can be used medicinally.

The mean content of flavonoids  in a cup of green tea is higher than that in the same volume of other food and drink items that are traditionally considered of health contributing nature, including fresh fruits, vegetable juice and wine.

White tea contains high levels of catechins, some of which reduce the occurrence of atherosclerotic plaques  and the severity of strokes. It’s also been shown to prevent cancer in non-human studies.

Green, oolong & Pu-erh teas are touted for their ability to increase metabolism and help with fat oxidation and weight loss.

Herbal tea is not necessarily made from a true tea plant but rather a combination of herbs, spices and other plant materials. They can be used medicinally as well depending on what’s in it.