Tea (from the plant Camellia sinensis) is the most popular beverage next to water, consumed by over two-thirds of the worlds population. About three billion kilograms of tea are produced and consumed yearly. Regular intake of tea is associated with an improved antioxidant status in vivo conditions that may contribute to the lowering risk of certain types of cancer, coronary heart disease, atherosclerosis, stroke, reduced mutagenicity and inflammation, protection against neurodegenerative diseases and increasing insulin sensitivity. Tea may contain alkaloids (caffeine), flavonoids (catechins), phenolic acids (gallic acid, coumaric acid, caffeic acid and chlorogenic acid) and volatile oils (essences). Animal studies have strongly supported the idea of tea being an efficient suppressor of oxidative stress in diabetic animals but human studies have faced inconsistency.