Drinking one to three cups of tea a day can reduce the risk of memory falling by 43 percent, claims study.
In one study, of about 1500 men and women in Singapore, drinking more than four cups a day cut the chances of cognitive decline by up to three-quarters, the Daily Mail reported.
It is believed that compounds found in tea may help protect against the poisons that damage the brain in Alzheimer's.
Possibilities among the compounds include theanine, a plant chemical found only in tea and in mushrooms.
Experts in the US examined several studies on the effect of caffeinated drinks on memory and mental alertness.
The thousands of men and women who took part in the study logged how often they drank tea or coffee and did a memory test, which is used in the initial stages of diagnosing Alzheimer's disease.
Up to ten years later, they resat the test and any fall in score was noted.
According to the study, the brain stayed sharper in the people who drank tea in all the studies that included the drink.
The study has been published in the journal Advances in Nutrition.