Regularly drinking green tea could protect the brain against Alzheimer's and other forms of dementia, according to scientists at Newcastle University.
The study showed chemicals created when the tea is digested help prevent the degeneration of brain cells.
Similar research has hinted the beverage could also help protect against some forms of cancer.
The Alzheimer's Research Trust said diet and lifestyle were important in assessing the risks of the disease.
The study is published in the academic journal Phytomedicine.
'Diet and lifestyle'
Project leader Dr Ed Okello, from the university's School of Agriculture, Food and Rural Development, said: "We found when green tea is digested, the resulting chemicals are actually more effective against key triggers of Alzheimer's development than the undigested form of the tea.
"In addition, we also found the digested compounds had anti-cancer properties, significantly slowing down the growth of tumour cells we were using in our experiments."
Lab experiments used tumour cell which were exposed to varying concentrations of different toxins as well as digested green tea compounds.
The digested chemicals protected the cells, preventing the toxins from destroying them, according to the team.
Dr Okello added: "There are many factors which have an influence on diseases such as cancer and dementia like a good diet, plenty of exercise and a healthy lifestyle.
"But I think it's fair to say that at least one cup of green tea every day may be good for you and I would certainly recommend it."
Rebecca Wood, chief executive of the charity Alzheimer's Research Trust, said: "These results are at a very early stage, so we can't make the leap of assuming that green tea can protect people from dementia.
"Diet and lifestyle almost certainly plays a part in every person's Alzheimer's risk."
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