Tea infusions, as used for brewed tea, are still considered safe. Instant tea drinks are also fine as they contain lower levels of the antioxidants naturally present in green tea, Parma-based EFSA said.

Consuming too many of these antioxidants can be harmful, which is why the amount contained in supplements can have a harmful effect on the liver.

Most supplements provide an intake of 5-1000 milligrammes, while tea infusions typically only contain 90-300 milligrammes, EFSA, which oversees food safety in the European Union, said.

Researchers determined that consuming over 800 milligrammes per day led to higher health risks, but the EFSA said experts could not yet determine a supplement dosage that would be entirely safe.

However, high consumption of green tea infusions did not indicate liver damage due to the drinks having a lower concentration of antioxidants.