Browsing the supplement aisle at your local drugstore or supermarket can feel overwhelming. In front of you are countless supplements claiming to provide everything from better heart health to improved cognitive function to weight loss. And while some supplements do deliver on their promises, many fall short. Worse yet, some could do more harm than good.
In fact, there's one supplement that has so much potential to cause harm that experts recommend you avoid it entirely. According to Courtney D'Angelo, MS, RD, a registered dietitian and author at Fit Healthy Momma, the worst supplement you can take is kava.
What is kava used to treat?
Kava, also known as kava kava, is an herbal supplement that is often used to treat anxiety—and research suggests that it can sometimes be effective in doing so.
A 2013 study published in the Journal of Clinical Pharmacology found that among 75 participants with generalized anxiety disorder who took either kava extract or a placebo over a six-week period, members of the kava group saw a "significant reduction" in anxiety as compared to the control group but experienced more headaches.
Despite the fact that this supplement may be beneficial to some, it doesn't come without negative side effects.
What are the dangers of taking kava supplements?
Unfortunately, it's not headaches alone that you could find yourself dealing with if you take kava supplements.
Kava may cause liver damage
"Kava can be harmful because it can damage your liver," says D'Angelo.
In 2002, the U.S. Food and Drug Administration (FDA) warned consumers, "Kava-containing products have been associated with liver-related injuries—including hepatitis, cirrhosis, and liver failure—in over 25 reports of adverse events in other countries. Four patients required liver transplants. The FDA has received a report of a previously healthy young female who required liver transplantation, as well as several reports of liver-related injuries."
Between 1999 and 2002 alone, healthcare practitioners in the U.S., Germany, and Switzerland identified 11 patients who suffered liver failure after using kava products, all of whom required liver transplants, according to findings published in the Centers for Disease Control and Prevention (CDC) journal Morbidity and Mortality Weekly Report.
Kava may impair motor skills
That's not the only potential danger associated with taking kava supplements, however. "Research has also shown that it can slow reaction time and impair motor skills," says D'Angelo.
A 2015 review of research published in the Australian and New Zealand Journal of Public Health reveals that kava may enhance the effects of alcohol, and that, in one study, individuals who consumed both prior to a driving simulation were "significantly impaired" by the combination.
However, as is the case with most supplements and medications, your mileage may vary, so make sure you speak to a healthcare professional before adding any new supplements to your routine.
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