Health Canada is ordering a more explicit warning on labels of green tea extract products over concerns about the risk of liver injury. The over-the-counter pills have become a popular option for those seeking to lose weight.
The change follows a federal safety review, prompted after Madeline Papineau, a 17-year-old in Cornwall, Ont., took the extract and quickly developed liver and kidney injury. Doctors were initially stumped by the damage, until the teen's sister mentioned she'd been taking a diet supplement.
Health Canada says the risk of liver injury has been noted on the labels of products containing green tea extract since 2008. But on Wednesday the agency announced it was "clarifying warnings" by asking manufacturers to include the following stronger wording on their product labels:
"Stop use if you develop symptoms of liver trouble such as yellowing of the skin/eyes (jaundice), stomach pain, dark urine, sweating, nausea, unusual tiredness and/or loss of appetite, and consult a health care practitioner."
"Rare, unpredictable cases of liver injury associated with green tea extract-containing products have been reported (in Canada and internationally)."
As part of a previous investigation, CBC's Marketplace discovered more than 60 documented cases worldwide of liver failure associated with green tea supplements reported in peer-reviewed journals. At least two deaths have been partially linked to taking the pills.
Green tea contains catechins, a type of antioxidant. And concentrated green tea extracts contain catechins at much higher levels than are found in the brewed version of the popular drink.
While green tea is often regarded as good for you, U.S. gastroenterologist Dr. Herbert Bonkovsky says green tea extract can be dangerous for some people at high doses.
"If you take enough of it, it can kill you," Bonkovsky said.
In a summary of its safety review findings issued on Wednesday, Health Canada said that although they are rare, "cases of liver injury continue to be reported in Canada and worldwide."
It said it knew of 11 cases of suspected liver injury associated with green tea extract in Canada between 2006 and 2016, although only two of those cases "had enough information to be fully assessed."
What remains unclear from the evidence, Health Canada said in an accompanying news release,"is why some people may be more susceptible than others to liver injury."
Specific warning for teens and children
The market for weight-management and well-being products in Canada is estimated to be worth about $304 million US a year, according to market research firm Euromonitor.
Health Canada is now asking, "as a precautionary measure," that companies licensed to make "natural health products containing green tea extract as a medicinal ingredient and that are intended for children and adolescents" either remove the green tea extract or revise the label to specify that the product is only intended for adults over 18 years of age.
Julie Papineau, Madeline Papineau's mother, said she is pleased with the stronger warning on green tea extract products but feels it doesn't go far enough.
"I stand by my position that this product should be recalled," she told Marketplace.
The department says that green tea "in any form, including as beverages, foods and an extract in natural health products, is considered generally safe for the majority of consumers."
Green tea extract is often a concentrated form.
Joyce Boudreau-Hearn, of Mulgrave, N.S., died of complications from liver failure in 2010 after multiple transplants led to infection. Her daughter, Jocelyn Stewart, says the 55-year-old had been healthy before she started taking a green tea extract sold as a weight-loss supplement.
"It says green tea extract — most of us link that to healthy," Stewart said. "Everybody buys a green tea; you can buy it anywhere. You think you will lose a few pounds. She lost her life."
While there are documented cases of the dangers, there are few examples of green tea extract actually aiding in long-term weight loss.
Dr. Sean Wharton, the medical director of several publicly funded weight-loss clinics in the Greater Toronto Area, describes weight-loss supplements as "hope in a bottle."
"If something is really difficult and we don't have terrific treatments for them," he said, "then the pharmacies and other places will be filled with these fake medications to try to give people fake hope in an area where people are looking for an answer."