Eye Earl Grey or English Breakfast just won’t cut it, though, according to Journal of Agricultural and Food Chemistry it has to be green tea. "Green tea is already known to be a powerful antioxidant, which could reduce our risk of a variety of diseases where so-called oxidative processes play a role, such as cancer, heart disease, and conditions associated with brain aging," says Carina Norris, author of The Food Manual (Haynes).
This latest research, which involved having rats drink green tea, showed that the anti-oxidative substances found in the green tea found their way to the eye tissues, remaining there for up to 20 hours afterwards.
As ever, experts advise caution when extrapolating your own behaviour from a study undertaken on rodents: "Studies showing the effects of green tea generally involve people drinking many cups per day," says Norris. "I'd suggest that you have to drink quite a lot in order to reap the benefits - probably upwards of four cups a day."