EFSA has assessed the safety of green tea catechins from dietary sources, following concerns regarding their possible harmful effects on the liver. EFSA concluded that catechins from green tea infusions and similar drinks are generally safe. When taken as food supplements, however, catechin doses at or above 800 mg/day may pose health concerns.

Green tea is widely consumed for its purported health benefits, but there have also been reports in the EU and beyond of possible harmful effects. EFSA’s assessment of green tea catechins was triggered by concerns from Nordic countries following reported cases of liver damage possibly associated with the use of green tea products.

Catechins are substances naturally present in green tea, the most abundant of which is epigallocatechin gallate (EGCG). In its safety assessment, EFSA looked at possible links between the consumption of EGCG in green tea infusions and food supplements and liver damage.

No concerns for infusions

For green tea infusions, EFSA’s experts concluded that there is generally no indication of liver damage even after high consumption, and that the few cases of liver damage reported in humans are likely due to rare and unpredictable reactions. Experts therefore considered catechins from green tea infusions brewed with hot water, and instant and ready-to-drink green tea beverages with similar catechin content, as generally safe.

For food supplements, EFSA’s experts concluded – on the basis of human studies conducted with volunteers under medical supervision – that doses of EGCG at 800 mg/day may be associated with initial signs of liver damage. While there was no indication of liver injury for doses below 800 mg/day from green tea supplements, experts were unable to identify a safe dose based on available data.

Catechin contents differ

Food supplements containing green tea catechins provide a daily EGCG intake ranging from 5-1000 mg. These food supplements are generally intended for adults. The average daily intake of EGCG resulting from the consumption of traditional green tea infusions ranges between 90 and 300 mg, but may reach up to 866 mg in adults who consume large quantities of these drinks.

Catechins in green tea extracts used in food supplements may be more concentrated, or have a different composition and pattern of consumption compared to catechins from green tea infusions. For example, infusions tend to be consumed together with food and spread throughout the day, while supplements, especially for slimming, are more likely to be taken in a fasting state and as a single daily dose.

Recommendations and next steps

To improve consumer protection, EFSA has recommended that further studies on the effects of green tea catechins be carried out. Experts also proposed clearer labelling of green tea products (in particular food supplements) regarding catechin content and their possible health risks. EFSA’s advice is now being forwarded to the European Commission, which will decide on the most appropriate risk management follow-up.