After water, tea is the most commonly consumed drink in the world (despite the attempts of Coca Cola!). More and more studies
are demonstrating the effectiveness of tea in promoting health and wellbeing. A recent study by Vinson and Zhang (1) has
indicated that simply drinking tea may be an inexpensive means of preventing diabetes and the complications that follow.
The researchers studied the effects of green and black tea on four groups of rates: a normal group (non-diabetic); a
diabetic control group, a group of rats with diabetes that were given green tea and a similar group who were given black
tea. Over three months, the teas were incorporated into the rats’ drinking water to the extent that they were effectively
drinking around 5 normal size cups of tea a day.
The rats’ blood and eye lenses were analysed to determine whether the teas
reduced blood glucose levels and reduced the incidence of cataracts (a common problem associated with diabetes).
The results indicated that both green and black teas significantly inhibited the formation of cataracts relative to the
control group that did not drink any tea.
The researchers commented that drinking the teas “significantly decreased glucose, and ………inhibited the pathological
pathways of diabetes in lens, plasma and red blood cells”.
Blood plasma glucose levels in the tea drinking diabetic
rats typically fell around 30%. In addition, the severity of cataracts amongst the diabetic rats was significantly
reduced by drinking tea (interestingly, black tea appeared to have a more beneficial effect than green tea).
This and other studies have shown that there are numerous health benefits from regular consumption of tea. Whether
consumed as a drink or as a supplement, research suggests that the components in tea can have a positive effect on a
number of conditions and disorders. Tea has the potential to play an indispensable role in the maintenance of health
and wellbeing.
(1) Vinson JA, Zhang J. Black and green teas equally inhibit diabetic cataracts in a streptozotocin-induced rat model of
diabetes. Journal of Agricultural and Food Chemistry 2005;53:3710-3713.