Can drinking tea really help to save your sight?

It seems an unlikely claim to make on behalf of a simple hot drink, but a US survey has been investigating the links between Britain’s most characteristic drink lower risks of glaucoma. Glaucoma¬†is a condition that damages the optic nerve by increased pressure, called intraocular pressure, in the eyeball. If left undiagnosed and untreated, glaucoma can eventually cause permanent loss of vision. Having a routine eye test every two years should pick up the condition before it becomes an issue.

Researchers in the US survey were interested in seeing whether caffeine had any effect (whether positive or negative) in whether pressure built up in the eye. Although a variety of drinks were consumed by the survey sample, including tea, coffee and iced tea, both caffeinated and decaff, only one appeared to have any effect. Drinking caffeinated hot tea, which, ironically, was the most unusual drink consumed, appeared to lower the risk of being diagnosed with glaucoma. The results were published in Britain in the British Journal of Ophthalmology.

How did the study work?

The criteria for participating in the survey was that you had to be over 40 years old (in fact, the average age of participants was 56), and have certain information available from previous eye tests, including photographs of the retina which shows any damage to the optic nerve.

Participants who drank more than six cups of hot, caffeinated tea a week appeared to have a 74% less risk of developing glaucoma. However, before you rush over to put the kettle on, the NHS advises caution in interpreting the data. As it was a one-off survey based on a snapshot in time, consumption can’t be definitively linked to prevention. Also, the number of tea-drinkers in the survey was too small to provide a working statistical sample, and participants’ answers were often based on estimation of how much of each type of drink they’d consumed.

The research, though, raises some interesting questions and may continue to be developed further in time.

For all your commercial hot drinks needs for your cafe or catering business, take a look at our main website to browse our range of coffee, accessories…and tea!