Turmeric Supplements and Liver Toxicity

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An increasing number of case reports have linked turmeric extract supplements to liver injury.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Liver injury associated with turmeric: Ten cases from the drug-induced liver injury network in the United States, and there are others too, including three cases reported in Australia and a series reported to the Italian Ministry of Health. Is turmeric really a new hepatotoxic substance? First of all, regardless of what the titles of the papers say, these cases appear to be from turmeric extract supplements, rather than turmeric the spice. It’s like green tea and green tea extract pills. Brewed green tea appears to be completely safe for the liver, but give people green tea extract supplements, and the livers of as many as 1 in 17 people becomes inflamed. So, we should consume our green tea in beverage form, not pill form, and similarly our turmeric in spice form at culinary doses, not capsules, unless they contain just a single ingredient: whole spice turmeric, not curcumin, not an extract, no other ingredients.

While turmeric extract supplements have a relatively safe side-effect profile even at high doses, there is an increasing number of case reports linking them to liver injury, especially when combined with agents such as piperine, a compound found in black pepper. As we’ve covered before, compounds like piperine are added to turmeric to enhance the bioavailability of curcumin––potentially contributing to its toxicity, as one reason curcumin may be so safe is that it is poorly absorbed. As we have cautioned before, piperine blocks liver detox enzymes that can make some substances like curcumin more potent. And turmeric curcumin supplement formulations with high bioavailability, such as nanoformulations, or those with added piperine, have been less investigated. There is a mistaken assumption that if a little is good, then more must be better. We’d never make that assumption for drugs, so why is it made for supplements?

In this case, more does not necessarily mean better. A review of nearly a hundred randomized controlled trials of turmeric or curcumin supplements for nonalcoholic fatty liver disease found that they successfully calmed liver inflammation. And guess which worked better? Low-dose supplements worked about 10 times better than high-dose ones.

There are caveats, though, even for whole food turmeric. As Dr. Greger has covered before, people who have a tendency to form kidney stones should be careful due to turmeric’s relatively high oxalate content. During a routine exam, this unfortunate man was found to have kidney failure due to his chronic turmeric intake, which led to oxalate nephropathy, where oxalate crystalizes in our kidneys. That was after taking only 2 grams or 2/3 of a teaspoon of turmeric every day for two years. And taking a few spoonfuls a day of the actual spice itself may indeed be enough to cause liver injury, as happened to this pregnant woman. Dr. Greger recommends only a quarter teaspoon a day in his Daily Dozen.

There’s also been concern about lead contamination of the whole food spice. Lead chromate has been used to make turmeric appear more yellow in Bangladesh, where much of turmeric sold in the United States is imported from, leading to multiple recalls. The wonderful news is food safety policies can work! Since the original paper of lead chromate contamination in turmeric from Bangladesh, the portion of market turmeric samples with detectable lead went from about 50 percent to zero. Unfortunately, there is still more work to be done, though. In four South Asian countries where more than 80 percent of the world’s turmeric is produced, 14 percent of samples had detectable lead above 2 ug/g. For context, this is 20 times higher than the U.S. Food and Drug Administration’s maximum allowable level for lead in candy. And some stores sold turmeric containing much higher levels of lead that would result in projected blood lead levels in children up to 10 times higher than the U.S. Centers for Disease Control’s threshold for concern.

This is a reminder that just because something is natural doesn’t mean it can’t cause harm. Turmeric dietary supplements are big business, estimated to account for $69 million in sales in the United States alone––though its popularity does help put the recent spate of liver toxicity cases in context. More than 10 million people in the United States take turmeric or curcumin supplements, so that would be like one case in a million. Some people may just be more susceptible genetically—in this case series, seven of the 10 patients had a genetic variant that’s relatively rare in the general population. Still, it’s safer for everyone to use the real thing and not some extract in some supplement. And please don’t let anyone inject turmeric or curcumin into your veins.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Liver injury associated with turmeric: Ten cases from the drug-induced liver injury network in the United States, and there are others too, including three cases reported in Australia and a series reported to the Italian Ministry of Health. Is turmeric really a new hepatotoxic substance? First of all, regardless of what the titles of the papers say, these cases appear to be from turmeric extract supplements, rather than turmeric the spice. It’s like green tea and green tea extract pills. Brewed green tea appears to be completely safe for the liver, but give people green tea extract supplements, and the livers of as many as 1 in 17 people becomes inflamed. So, we should consume our green tea in beverage form, not pill form, and similarly our turmeric in spice form at culinary doses, not capsules, unless they contain just a single ingredient: whole spice turmeric, not curcumin, not an extract, no other ingredients.

While turmeric extract supplements have a relatively safe side-effect profile even at high doses, there is an increasing number of case reports linking them to liver injury, especially when combined with agents such as piperine, a compound found in black pepper. As we’ve covered before, compounds like piperine are added to turmeric to enhance the bioavailability of curcumin––potentially contributing to its toxicity, as one reason curcumin may be so safe is that it is poorly absorbed. As we have cautioned before, piperine blocks liver detox enzymes that can make some substances like curcumin more potent. And turmeric curcumin supplement formulations with high bioavailability, such as nanoformulations, or those with added piperine, have been less investigated. There is a mistaken assumption that if a little is good, then more must be better. We’d never make that assumption for drugs, so why is it made for supplements?

In this case, more does not necessarily mean better. A review of nearly a hundred randomized controlled trials of turmeric or curcumin supplements for nonalcoholic fatty liver disease found that they successfully calmed liver inflammation. And guess which worked better? Low-dose supplements worked about 10 times better than high-dose ones.

There are caveats, though, even for whole food turmeric. As Dr. Greger has covered before, people who have a tendency to form kidney stones should be careful due to turmeric’s relatively high oxalate content. During a routine exam, this unfortunate man was found to have kidney failure due to his chronic turmeric intake, which led to oxalate nephropathy, where oxalate crystalizes in our kidneys. That was after taking only 2 grams or 2/3 of a teaspoon of turmeric every day for two years. And taking a few spoonfuls a day of the actual spice itself may indeed be enough to cause liver injury, as happened to this pregnant woman. Dr. Greger recommends only a quarter teaspoon a day in his Daily Dozen.

There’s also been concern about lead contamination of the whole food spice. Lead chromate has been used to make turmeric appear more yellow in Bangladesh, where much of turmeric sold in the United States is imported from, leading to multiple recalls. The wonderful news is food safety policies can work! Since the original paper of lead chromate contamination in turmeric from Bangladesh, the portion of market turmeric samples with detectable lead went from about 50 percent to zero. Unfortunately, there is still more work to be done, though. In four South Asian countries where more than 80 percent of the world’s turmeric is produced, 14 percent of samples had detectable lead above 2 ug/g. For context, this is 20 times higher than the U.S. Food and Drug Administration’s maximum allowable level for lead in candy. And some stores sold turmeric containing much higher levels of lead that would result in projected blood lead levels in children up to 10 times higher than the U.S. Centers for Disease Control’s threshold for concern.

This is a reminder that just because something is natural doesn’t mean it can’t cause harm. Turmeric dietary supplements are big business, estimated to account for $69 million in sales in the United States alone––though its popularity does help put the recent spate of liver toxicity cases in context. More than 10 million people in the United States take turmeric or curcumin supplements, so that would be like one case in a million. Some people may just be more susceptible genetically—in this case series, seven of the 10 patients had a genetic variant that’s relatively rare in the general population. Still, it’s safer for everyone to use the real thing and not some extract in some supplement. And please don’t let anyone inject turmeric or curcumin into your veins.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Doctor's Note

A note from Dr. Greger:
I am thrilled to introduce Dr. Kristine Dennis, our Senior Research Scientist. Dr. Dennis is an experienced nutrition and public health scientist who joined NutritionFacts to expand our research capacity — diving deep into the research, writing scripts, and now, narrating her own videos! You’ll continue to see videos from both of us interspersed in no particular order. I’m so happy Kristine is with NutritionFacts to help expand our capacity and perspectives.

These are the videos I mentioned:

For more on turmeric, see the turmeric topic page.

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