Does black cohosh belong on liver damage database?

The free database of evidence-based information is meant for health care professionals and for researchers studying liver injury associated with prescription and over-the-counter drugs, herbals, and dietary supplements. The LiverTox​ database can be used to identify basic and clinical research questions to be answered and to chart optimal ways to diagnose and control drug-induced liver injury.

The database is, of course, heavily weighted toward drug information. It includes information on about 700 drugs, with far fewer herbal ingredients appearing on the list. According to the NIH, drug-induced liver injury is the leading cause of acute liver failure in the United States, accounting for at least half of cases. It occurs at all ages, in men and women, and in all races and ethnic groups. Drug-induced liver disease is more likely to occur among older adults because they tend to take more medications than younger people.

"Because drug-induced liver disease is not a single, common disease, it is very difficult to diagnose, with each drug causing a somewhat different pattern of liver damage,"​ said Jay H. Hoofnagle, M.D., the major creator of LiverTox and director of the Liver Disease Research Branch at NIH’s National Institute of Diabetes and Digestive and Kidney Diseases.

Small number of cases could skew data​

But the question for some of the supplements on the list is whether they should be on there at all.  The very small number of cases of liver problems associated with supplements means that outliers will have an outsized effect on the data.

“This thing about hepatotoxicity and herbs is a very challenging issue for manufacturers, researches and clinicians,”​ Mark Blumenthal, executive director of the American Botanical Council, told NutraIngredients-USA.

“It’s very difficult to try to come up with definitive data for botanicals and other items that have ​no previous history of hepatotoxicity.”​

Take the case of black cohosh, the herb listed in the database with the most number of cases associated with it.  Used in menopause support products, the herb is, according to the database, implicated in “many instances of clinically apparent, acute liver injury,”​ going on to state that the herb is implicated in more than 50 such cases.

The entry does say that “black cohosh does not appear to be inherently hepatotoxic, and the clinical features of cases suggest that the liver injury is an idiosyncratic reaction.”​

True black cohosh not linked to liver problems​

Despite what the database may have to say, Blumenthal said that there is little data connecting black cohosh with liver problems.

“With black cohosh specifically, there is still no known adverse affect with black cohosh with respect to liver damage,”​ he said.

The discrepancy lies in what was actually in the bottle.  While the case reports definitely state that the patients fell ill after using a supplement that contained black cohosh, it’s unclear whether identity tests were performed in the supplements.

“The USP empaneled a group to look at this question because there had been reports of dietary supplements labeled as containing black cohosh causing liver damage,”​ Blumenthal said.

“You’ll notice how I phrased that: ‘labeled as containing black cohosh.’ You know what’s coming next. Apparently some of the implicated supplements did not contain black cohosh but contained any one of three Chinsese actaea species.”​

It’s illegal to sell these adulterants as black cohosh, Blumenthal said, but it still is done.  He cited a recent review that found that about a quarter of the products sampled that were labeled as containing black cohosh actually contained something else.

Canadian inquiry implicates adulterants​

Canadian health authorities recently looked at the issue, when they had reports of three cases of liver damage associated with black cohosh. In those cases, Blumenthal said, two of the three products consisted only of the Chinese herb, while the third had a mixture of the true North American black cohosh and the Chinese adulterant. The findings at least implicate the Chinese adulterants in the observed liver damage, he said.

“It could be that some of these cases, maybe all of these (mentioned in the database), could be attributable to the Chinese adulterant species,”​ Blumenthal said.

The database serves health professionals, some of whom might be working under pressing conditions in trying to help ill patients. If a patient is suffering liver damage after taking a supplement whose label said it contained black cohosh but they had ingested an adulterant instead, it’s probably a moot point for that practitioner if the information in the database helps treat the patient. But if the information does in fact describe cases pertaining to the adulterants and not the true ingredient, it could be misleading and could unfairly taint the true ingredient.