An investigation by a coalition of dietary supplement makers into a possible link between popular health supplement kava kava and an increased risk of liver failure has exonerated the herb, although the study's author urged that it be used with caution.
Sales of kava kava have recently been restricted or banned in several European countries and Canada due to several reports linking it to liver toxicity and failure. But the findings of a three-month evaluation of the herb by the coalition have given a tentative all clear to the use of the supplement.
The study carried out by Dr Donald Waller, a toxicologist and professor at the University of Illinois in Chicago, looked at more than 50 case reports from the United States and Germany. While all of the German cases reported some liver-associated effect, only five of the US cases had any such indication.
Dr Waller concluded that there was "no clear evidence that the liver damage reported in the US and Europe was caused by the consumption of kava," but added that "the medical community and the general public should be made aware that concomitant intake of prescription drugs associated with liver damage, excessive alcohol consumption and pre-existing liver disease may preclude any kava consumption".
Following the publication of the study, the coalition members met with officials from the Food & Drug Administration at the end of last week to discuss the potential threat of tighter regulations on kava kava in the US.
One coalition member, the National Nutritional Foods Association, said that the agency representatives had commented simply that the FDA was still evaluating case reports involving kava use in order to determine future actions, if any.
The coalition also included the American Herbal Products Association, the Council for Responsible Nutrition and the Utah Natural Products Alliance.