The concept of “8 by 8” became ingrained in society, as did the belief that only water would do. Common wisdom was that tea would make a person more dehydrated, in need of additional water intake. Unfortunately, even though this idea has been proven to be untrue, many people have not gotten the message.
According to the Institute of Medicine, drinking any beverage containing water will help keep the body hydrated. Happily, this list includes tea.
“We should be telling people that beverages like tea and coffee contribute to a person’s fluid needs and despite their caffeine content, do not lead to dehydration,” wrote Spero Tsindos from La Trobe University’s Department of Dietetics & Human Nutrition in the June 2012 Australian and New Zealand Journal of Public Health.
A study sponsored by the UK Tea Advisory Panel corroborated these statements. Researchers assembled 21 volunteers who would consume four cups of tea on one day of the study and four cups of hot water on the other day of the study. (Some participants began with tea and the rest began with the water. Each person switched for the second day.) Hydration levels were measured using blood and urine samples. Researchers found no differences in hydration levels in the participants whether they consumed water or tea.
Read more in The Telegraph.