Black tea, green tea and white tea are all associated with various health benefits. A new study now reveals that two compounds in black tea can approve both visual and hearing attention span in humans. The two black tea compounds were L-theanine and caffeine.

Tea is the main source of L-theanine in the diet and so usually gets consumed with caffeine. A group of 29 healthy people aged between 18 and 45 took part in the study, consuming either a drink containing L-theanine and caffeine or a placebo on two occasions six days apart. The amounts of L-theanine and caffeine were similar to that you would find in a typical cup of black tea. After consuming their drink, attention span and other aspects of cognitive functioning were measured. Both visual and hearing attention span improved after consuming the drink with the two black tea compounds, compared to placebo. Therefore, the ‘lift’ you often feel when consuming black tea, with or without milk added, is now backed by some scientific evidence.

Other evidence supports the health benefits of black tea. For instance, a UK review of 20 studies showed that drinking around four cups of black tea a day reduces the risk of heart attack and reduces cholesterol. Another study, of 26,500 middle-aged smokers showed that men drinking more than two cups of black tea a day were 20% less likely to have a stroke. It is true that very large amounts of caffeine can raise blood pressure, particularly among those who already have hypertension, but moderate amounts are beneficial. Also, black tea contains plant antioxidants called polyphenols which are anti-inflammatory; they may support brain and mental function, as well as decreasing the risk of heart attack.

Source:

Einöther S et al L-theanine and caffeine improve task switching but not intersensory attention of subjective alertness Appetite 2010,doi:10.1016/j.appet.2010.01.003