STUDY FINDS
Millions of Americans are unknowingly putting their liver health at risk by consuming potentially harmful herbal supplements.
That’s the conclusion of a new study in which University of Michigan researchers found an estimated 15.6 million U.S. adults regularly use at least one of six botanical products linked to liver damage.
This number is comparable to the number of people taking common prescription medications known to affect the liver.
The study, published in JAMA Network Open, analyzed data from a nationally representative survey to investigate the use of six common herbal supplements:
- Turmeric
- Green tea extract
- Garcinia cambogia
- Black cohosh
- Red yeast rice
- Ashwagandha
These popular supplements have been associated with liver injury in previous research as well.
“Herbal and dietary supplements (HDSs) include a multitude of products consumed by millions of people every day to improve their general health and to treat minor ailments,” study first author Dr. Alisa Likhitsup and the team write in their report.
“The largest group of HDS products used include multivitamins, minerals, vitamin D, omega-3 fatty acid, and calcium with well-defined ingredients on the label. However, an estimated 5% to 12% of HDS products are plant-derived, complex multi-ingredient botanicals,” the researchers explain.
“Chemical analyses of HDS products associated with confirmed liver toxic effects show frequent discrepancies between product labels and detected ingredients.”
The most commonly used supplement was turmeric, with an estimated 11.4 million users. Green tea extract followed, with about 3.3 million users. These numbers may come as a surprise to many, as these products are often marketed as health-boosting and are widely available over the counter.
Unlike prescription medications, herbal supplements are not strictly regulated by the Food and Drug Administration (FDA). This lack of oversight means that manufacturers don’t have to prove their products are safe or effective before putting them on the market. Additionally, the contents of these supplements can vary widely between brands and even between batches of the same product.
The study found that supplement users were more likely to be older, female, non-Hispanic White, and have a higher education level and income compared to non-users. They were also more likely to have certain health conditions, such as arthritis, thyroid disorders, and cancer.
Interestingly, the vast majority of people taking these supplements did so without a healthcare provider’s recommendation. Many users reported taking the products to improve or maintain their health, prevent health problems, or boost immunity. For example, most turmeric users took it for joint health or arthritis, while Garcinia cambogia was primarily used for weight loss.
The researchers stress that their findings don’t mean everyone taking these supplements will experience liver problems. However, they hope their study will raise awareness about the potential risks and encourage more research into the safety of these popular products. As the herbal supplement industry continues to grow, with sales reaching over $150 billion in 2023, it’s more important than ever for consumers to be informed about what they’re putting into their bodies.
Paper Summary
Methodology
The researchers used data from the National Health and Nutrition Examination Survey (NHANES), a large-scale study that regularly collects health information from a representative sample of the U.S. population. They looked at data from 9,685 adults surveyed between 2017 and early 2020. Participants were asked about their use of dietary supplements in the past 30 days. The researchers then identified users of the six specific botanical products of interest and compared their characteristics to non-users of herbal supplements.
Key Results
The study found that 4.7% of U.S. adults, or about 15.6 million people, used at least one of the six potentially harmful botanical products. Turmeric was the most commonly used, followed by green tea extract. Users of these supplements were generally older, more educated, and more likely to have certain health conditions like arthritis. Most users took the supplements on their own initiative, not based on a healthcare provider’s recommendation.
Study Limitations
The study relied on self-reported data, which can be subject to recall bias. Also, because it was a cross-sectional study (a snapshot in time), it couldn’t determine if supplement use actually caused any liver problems. The study also couldn’t verify the exact contents of the supplements people were taking, as herbal products can vary widely in their composition.
Discussion & Takeaways
The researchers emphasize that while these supplements are popular, they’re not regulated like prescription drugs. This means their safety and effectiveness aren’t thoroughly tested before they hit the market. The study highlights the need for more research into the potential risks of these products and better education for both healthcare providers and the public about herbal supplement use.
The authors suggest that healthcare providers should routinely ask patients about supplement use and that consumers should be more cautious about taking these products without medical advice. They also call for more stringent regulation of the herbal supplement industry to ensure product safety.
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