Millions of Americans consume supplements that contain potentially hepatoxic botanical ingredients, according to a recent study, with the research team also expressing concern about frequent mislabelling.
The findings of the University of Michigan-led study that analysed data from the National Health and Nutrition Examination Survey (NHANES) were published in JAMA Network.
Over a 30-day period, 4.7% of the adults surveyed (from 2017 to 2020) took 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 into the ongoing NIH-funded Drug-Induced Liver Injury Network (DILIN) study," said lead author Alisa Likhitsup, MD, MPH, clinical assistant professor of Medicine at the University of Michigan.
“But it was difficult to say how many people were using these supplements and why. The major finding is the large number of Americans taking these products – an estimated 15m people take them on a regular basis.”
News-Medical.net reports that prior research in the field had established the specific botanicals studied as potentially hepatoxic.
Supplements are of particular concern for the researchers for several interrelated reasons: lack of government regulation, insufficient attention in medical screenings and frequent mislabelling.
“In a previous study, we found that there was a great deal of mislabelling of some of these products,” said Robert Fontana MD, Michigan Medicine hepatologist, professor of medicine and the study’s senior author.
“When we performed analytical chemistry, we 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.”
Mislabelling is enabled by lack of regulation, said the authors, 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,” said Likhitsup, a transplant hepatologist.
“So, when doctors see patients in the office, they don’t necessarily ask about supplement use or take into consideration their effects.”
In the studied population, 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%).
Most users reported consuming the botanicals on their own and not on the advice of a doctor.
The most common reason given for taking the botanicals was 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.
One impetus for this research is the growth of herbal and dietary supplements industry.
The paper notes that there are more than 80 000 unique supplement products available for purchase worldwide and that supplement sales surpassed $150bn in the United States in 2023, a figure that rivals the combined sales of prescription drugs.
Another study had found a 70% increase in liver transplants due to injury caused by supplements from 2010-2020, compared with 1994-2009.
The JAMA study was not able to establish any kind of causal relationship between consumption of the six botanicals and liver injury, since it was intended to assess supplement exposure in the general US population.
Given the lack of regulation, however, 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 alarm,” Fontana said.
“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.”
Study details
Estimated Exposure to 6 Potentially Hepatotoxic Botanicals in US Adults
Alisa Likhitsup, Vincent Chen, Robert Fontana.
Published in JAMA Network Open on 5 August 2024
Abstract
Importance
Use of herbal and dietary supplements (HDSs) accounts for an increasing proportion of drug hepatotoxicity cases. Turmeric or curcumin, green tea extract, Garcinia cambogia, black cohosh, red yeast rice, and ashwagandha are the most frequently reported hepatoxic botanicals, but their prevalence and reasons for use in the general population are unknown.
Objective
To assess the prevalence and clinical characteristics of adult consumers of 6 potentially hepatoxic botanicals.
Design, Setting, and Participants
This survey study analysed nationally representative data from the National Health and Nutrition Examination Survey (NHANES), a nationally representative, cross-sectional survey of the general US population. Prescription drug and HDS exposure data in the past 30 days were analysed, and 2020 US Census data were used for population estimates. Data were analysed July 1, 2023, to February 1, 2024.
Exposures
Adult NHANES participants enrolled between January 2017 and March 2020.
Main Outcomes and Measures
Baseline weighted characteristics of HDS users and users of 6 potentially hepatotoxic botanical products were compared with non–HDS users. Multivariable analysis was undertaken to identify factors associated with HDS use or at-risk botanical use.
Results
Among 9685 adults enrolled in this NHANES cohort, the mean (SE) age was 47.5 (0.5) years, and 51.8% (95% CI, 50.2%-53.4%) were female. The overall prevalence of HDS product use was 57.6% (95% CI, 55.9%-59.4%), while the prevalence of using the 6 botanicals of interest was 4.7% (95% CI, 3.9%-5.7%). Turmeric-containing botanicals were most commonly used (n = 236), followed by products containing green tea (n = 92), ashwagandha (n = 28), Garcinia cambogia (n = 20), red yeast rice (n = 20), and black cohosh (n = 19). Consumers of these 6 botanicals were significantly older (adjusted odds ratio [AOR], 2.36 [95% CI, 1.06-5.25]; P = .04 for 40-59 years of age and AOR, 3.96 [95% CI, 1.93-8.11]; P = .001 for ≥60 years of age), had a higher educational level (AOR, 4.78 [95% CI, 2.62-8.75]; P < .001), and were more likely to have arthritis (AOR, 2.27 [95% CI, 1.62-3.29]; P < .001) compared with non–HDS users. An estimated 15 584 599 (95% CI, 13 047 571-18 648 801) US adults used at least 1 of the 6 botanical products within the past 30 days, which was similar to the estimated number of patients prescribed potentially hepatotoxic drugs, including simvastatin (14 036 024 [95% CI, 11 202 460-17 594 452]) and nonsteroidal anti-inflammatory drugs (14 793 837 [95% CI, 13 014 623-16 671 897]). The most common reason for consuming turmeric and green tea was to improve or maintain health.
Conclusions and Relevance
In this survey study, an estimated 15.6 million US adults consumed at least 1 botanical product with liver liability within the past 30 days, comparable with the number of people who consumed non-steroidal anti-inflammatory drugs and a commonly prescribed hypolipidemic drug. Given a lack of regulatory oversight on the manufacturing and testing of botanical products, clinicians should be aware of possible adverse events from consumption of these largely unregulated products.
JAMA Network article – Estimated Exposure to 6 Potentially Hepatotoxic Botanicals in US Adults (Open access)
News-Medical.net article – Research reveals widespread use of potentially liver-damaging botanicals (Open access)
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