The Norwegian Food Safety Authority (NFSA) is warning consumers about unspecified, high-dose green tea products (Camellia sinensis) after they were linked to liver complaints, even though the details of consumption have not been revealed.
NFSA senior advisor Ragnhild Steineger told us the agency was still analysing the adverse event reports that came to its attention following several hospitilisations and so was not releasing details about the exact products, nor how they were consumed. But in the public interest it felt compelled to envoy the public warning as other regulators have done sporadically over the years.
“These reports come from doctors and hospitals and so we take them seriously – it is part of a warning system we have in place – so there are strong suspicians but at this satge there is no direct proof.”
Steineger said the agency was working in conjunction with the Norwegian Medicines Agency (NMA) to determine the extent of the problem that has been linked to liver hepatotoxicity but not death.
Dialogue with trade groups on the matter was ongoing, she said, noting a focus on high-dose products sold online.
“NFSA recommends consumers to be cautious when using such products,” the agency said. “Before any purchase online [they] should acquire thorough information about the supplement.”
“Some supplements can have unwanted effects when taken with medications and when taken before, during and after surgery. It is therefore important to ask your doctor whether you can take the supplement if you are taking medication or to undergo an operation.”
“Always tell your doctor about any use of pharmaceuticals, plant-based medicines and supplements.”
Mechanisms need defining
Commenting, Robert Verkerk, PhD, chief executive and scientific officer at the Alliance for Natural Health-International (ANH-I), said green tea extracts’ popularity as a weight loss aid, and frequency of inappropriate dosing, meant such situations did arise on occasion. As did the presence of low-QC manufacturers.
“This appears to be the same issue that hit France and Spain around 10 years ago,” Dr Verkerk said.
“It appears to be down to sporadic hepatotoxicity linked to high strength green tea extracts, generally among people using the products for weight loss. The mechanism isn’t clear, and it may have as much – or more – to do with contamination/quality issues with the green tea extract, as it is is with the susceptibility of an individual - allergy, genetic polymorphisms, pre-existing liver damage etc.”
Some studies have highlighted such issues.
Green tea extracts are not backed by the European Food Safety Authority (EFSA) to aid weight loss.
The agency’s opinion is here .