More than 15 million US adults take supplements that may be toxic to the liver, according to a new study. Over a 30-day period, 4.7% of the adults surveyed in the National Health and Nutrition Examination Survey conducted from 2017 to 2020 took herbal and dietary supplements containing at least one of the botanicals of interest to the authors: turmeric; green tea; ashwagandha; black cohosh; garcinia cambogia; and red yeast rice-containing products.

The authors became interested in the topic when they saw cases of liver toxicity from herbal and dietary supplement use in people involved in another large US National Institutes of Health study.

In the current study, 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.

The authors conclude, “In light of the lack of regulatory oversight on the manufacturing and testing of botanical products, it is recommended that clinicians obtain a full medication and HDS [herbal dietary supplement] use history when evaluating patients with unexplained symptoms or liver test abnormalities. Considering widespread and growing popularity of botanical products, we urge government authorities to consider increasing the regulatory oversight on how botanicals are produced, marketed, tested, and monitored in the general population.”

To download the study, published in JAMA Network Open, click here