Researchers Warn Clinicians About Links Between Certain Supplements and Liver Toxicity

Millions of Americans are consuming supplements that may contain potentially hepatotoxic botanical ingredients, according to a recent study by researchers at the University of Michigan. The study, published in JAMA, analyzed data from the National Health and Nutrition Examination Survey conducted from 2017 to 2020 and found that 4.7 percent of surveyed adults took herbal and dietary supplements containing at least one of the botanicals of concern: turmeric, green tea, ashwagandha, black cohosh, garcinia cambogia, and red yeast rice products.

Alisa Likhitsup, MD, the lead author and a clinical assistant professor of Medicine at U-M, explained that their interest in the subject arose from cases of liver toxicity linked to herbal and dietary supplements observed in the ongoing NIH-funded DILIN study. "The major finding here is the large number of Americans taking these products, with an estimated 15 million adult Americans using them regularly," Dr. Likhitsup stated.

The study highlights several interrelated issues with supplements: lack of government regulation, insufficient attention during medical screenings, and frequent mislabeling. "We found about a 50 percent mismatch between stated ingredients on the label and the actual contents," said Robert Fontana, MD, senior author and professor of medicine. This discrepancy means that consumers often do not know what they are ingesting, which is alarming given the potential for liver toxicity, Dr. Fontana added.

Despite the risks, many users reported taking these botanicals without medical advice, primarily for health maintenance or specific benefits such as joint health, energy improvement, or weight loss. For instance, 26.8 percent of turmeric users took it for joint health or arthritis, while 27.2 percent of green tea users sought increased energy levels.

According to authors, this research underscores the rapid growth of the herbal and dietary supplements industry, with over 80,000 unique products available globally and U.S. sales surpassing $150 billion in 2023. The study also noted that the industry expansion has been accompanied by a 70 percent increase in liver transplants due to supplement-induced injuries from 2010-2020, compared to 1994-2009.

While the JAMA study did not establish a causal relationship between the consumption of the six botanicals and liver injury, it aimed to assess supplement exposure in the general U.S. population. Given the lack of regulation, the researchers emphasize the importance of awareness among both clinicians and patients about the potential risks associated with these supplements.

"We're not trying to create alarm," said Dr. Fontana. "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."

For integrative practitioners, this study serves as a crucial reminder to inquire about supplement use during patient consultations and consider the potential hepatotoxic risks associated with popular botanical ingredients. By staying informed and vigilant, practitioners can better guide their patients in making safe and informed choices regarding supplement use.