Are the everyday supplements damaging the liver? Experts weigh in

We take numerous supplements daily. From the ones that enhance workout performance to those that boost skin and hair health, the supplements industry is booming. But are those supplements you take for added benefits putting your liver at risk? A recent study suggests that the herbal and dietary supplements that people take every day may pose a risk to liver health.

A study from the University of Michigan found that several supplements contain potentially hepatotoxic botanical ingredients. The findings are published in JAMA. The researchers analyzed data from the National Health and Nutrition Examination Survey collected between 2017 and 2020. They found that 4.7% of US adults reported using herbal and dietary supplements containing at least one of the botanicals of interest: turmeric; green tea; ashwagandha; black cohosh; garcinia cambogia; and red yeast rice containing products.

“Our interest started when we saw cases of liver toxicity from herbal and dietary supplement use in people enrolled in the ongoing NIH-funded DILIN study. But it was difficult to say how many people were using these supplements and why. The major finding here is the large number of Americans taking these products, with an estimated 15 million adult Americans taking them on a regular basis,” Alisa Likhitsup, clinical assistant professor of Medicine at U-M and lead author, said in a statement.

Previous research has found the specific botanicals studied as potentially hepatotoxic. The recent study looks at the longstanding concerns about the supplement industry, such as a lack of government regulation, insufficient attention in medical screenings, and frequent mislabeling.

“In a previous study, we found that there was a great deal of mislabeling of some of these products. We performed analytical chemistry and found about a 50% mismatch between stated ingredients on the label and what they actually contained, which is quite alarming. If you buy a supplement and it says it has a certain ingredient, it's basically a coin flip if that’s true or not,” Robert Fontana, Michigan Medicine hepatologist, professor of medicine, and senior author, said.

Due to a lack of regulation, there was mislabeling, and since their effects are not well understood, clinicians often will not ask patients what supplements they are taking.

“We weren't aware that so many people were taking these supplements. So, when doctors see patients in the office, they don't necessarily ask about supplement use or take into consideration their effects,” Likhitsup, a transplant hepatologist, noted.

In the participants, the highest proportion of people consumed turmeric (3.46%), followed by green tea (1.01%), ashwagandha and black cohosh (0.38%), garcinia cambogia (0.27%), and red yeast rice products (0.19%). They took the supplements on their own and not on the advice of a doctor. They consumed the supplements to improve or maintain health.

Of the turmeric users, 26.8% consumed the products specifically for supposed benefits for joint health or arthritis, while 27.2% of the green tea users were hoping to improve their energy levels. The majority of the garcinia cambogia users hoped it would help them lose weight.
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A study hinted that there was a 70% increase in liver transplants due to injury caused by supplements from 2010-2020, compared to 1994-2009. Though the new study wasn’t able to establish any kind of causal relationship between consumption of the six botanicals and liver injury, the researchers still hope to make clinicians and patients aware of just how much is still unknown about these supplements.

“We're not trying to create an alarm. We're just trying to increase awareness that the over-the-counter supplements people are taking and buying have not been tested nor necessarily proven to be safe,” Fontana said.