A cup of tea a day can keep dementia away, according to a study from the National University of Singapore, which found that tea can slash the risk of dementia in people aged 55 and older.

Drinking tea cuts the risk of cognitive impairment in older people in half, but the news is even better for those who are genetically at risk of Alzheimer's. In people who carry the APOE e4 gene, tea reduces the risk by as much as 86 percent.

The researchers also discovered that the ability of tea to protect the brain isn't limited to a particular type of tea, as long as the tea is brewed from tea leaves, such as green, black or oolong tea.

"While the study was conducted on Chinese elderly, the results could apply to other races as well," said Assistant Professor Feng Lei from National University of Singapore's (NUS) Yong Loo Lin School of Medicine.

"Our findings have important implications for dementia prevention," Feng continued. "Despite high-quality drug trials, effective pharmacological therapy for neurocognitive disorders such as dementia remains elusive and current prevention strategies are far from satisfactory.

"Tea is one of the most widely consumed beverages in the world," he explained. "The data from our study suggests that a simple and inexpensive lifestyle measure such as daily tea drinking can reduce a person's risk of developing neurocognitive disorders in late life."

"Based on current knowledge, this long term benefit of tea consumption is due to the bioactive compounds in tea leaves, such as catechins, theaflavins, thearubigins and L-theanine," said Feng. "These compounds exhibit anti-inflammatory and antioxidant potential and other bioactive properties that may protect the brain from vascular damage and neurodegeneration."

The study was published in The Journal of Nutrition, Health & Aging.

Other studies have found that tea protects the brain. In Alzheimer's patients, amyloid protein in the brain forms into clumps and fastens onto nerves in brain cells, causing them to die. Scientists at Britain's University of Leeds found that treating the proteins with extracts of green tea and resveratrol disrupted the ability of amyloid to clump.

In addition, a 2016 Spanish study found that a polyphenol found in green tea called epigallocatechin gallate (EGCG), improves brain function in people with Down syndrome. Researchers found that EGCG improved scores on memory and behavior tests.