Caffeine can slow the growth of brain tumor cells according to researchers led by Kang Sang-soo of Gyeongsang National University and C. Justin Lee of the Korea Institute of Science and Technology in Seoul, South Korea.

The research team, comprising scientists from Seoul National University, Gyeongsang National University, and Emory University in Atlanta, said that animal test results showed regular caffeine found in coffee and green tea to have "strongly repressed the growth of inositol trisphosphate receptor (IP3R) closely linked to glioblastoma, which is the most common and aggressive type of primary brain tumour found in humans," adding that calcium plays a primary role in spreading glioblastoma tumour cells in humans, and that IP3R directly contributes to the amount of calcium released.

They found a sub-type of IP3R, or IP3R3, to be very active among brain cancer patients and that caffeine stymies the spread of such compounds, resulting in less tumor growth in the brain and blocking cancer cells from spreading to other parts of the body.

"This is the first type of discovery showing caffeine to have an inhibitive effect on the growth of glioblastoma, and thus we expect it to have a monumental impact on related studies," said Lee Chang-joon, who led the study. The amounts of caffeine used in the animal tests were equivalent to an average daily consumption of between of two to five cups of tea or coffee daily in human.