Over the past decades, turmeric has become increasingly popular in the West.
Turmeric and curcumin — the active ingredient in turmeric — are big business. In 2021, the curcumin market was valued at more than $73 million.
It’s projected to exceed $155 million by 2029. And one of the most common uses of curcumin is in supplements.
More recently, turmeric has been getting attention for all the wrong reasons: Scientists have found links between it and liver damage. In this article, we’ll drill into the details.
At ZOE, we’re not in the business of scaremongering, so we’ll get right to the point.
If you like adding turmeric to your curries and lattes, don’t worry, there are no health concerns at all. In fact, adding spices to your food can support good health.
The recent news is about supplements. Specifically, ones that contain a compound called piperine. However, the risks are still minimal.
Right, let’s start at the beginning.
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Turmeric and curcumin
Manufacturers make turmeric, the delicious spice, by powdering the dried rootstalk of turmeric plants.
While humans have prized it for its health benefits for centuries, there’s no strong evidence that this spice can help treat any medical conditions.
The main active ingredient is a bright yellow compound called curcumin.
However, when you consume turmeric, very little curcumin reaches your blood — in other words, it has low “bioavailability.”
This is partly because curcumin doesn’t dissolve readily in water, and your gut doesn’t easily absorb it. So, most curcumin comes out in your poop.
Any curcumin that does get absorbed is broken down quickly.
But when you pair curcumin with piperine — a compound in black pepper — its bioavailability increases by up to 2,000%. That’s why many curcumin or turmeric supplements also contain piperine.
OK, so why are we talking about turmeric and liver health today?
Turmeric and liver health
In the last few years, scientists have published several case studies linking turmeric supplements to liver injury.
Most recently, the Drug‐Induced Liver Injury Network (DILIN) helped fund a scientific investigation into 10 cases.
To identify these, the researchers took data from the DILIN, including 2,392 cases of drug-induced liver injury. Almost 1 in 5 cases were due to herbal and dietary supplements, and 3% were attributed to turmeric.
Among the 10 case studies that the team ultimately chose, none of the patients had a history of liver disease, and none drank excessive amounts of alcohol — a risk factor for the condition.
Five of the patients needed hospital treatment, and one person died of liver failure.
There have been other medical reports linking turmeric supplements to liver injuries. For instance, a review from 2020 describes seven cases of hepatitis (liver inflammation) linked to curcumin supplements in Tuscany between December 2018 and July 2019.
The authors of that paper also identified another 23 similar case studies from around the globe.
What’s going on?
A great deal of research has shown that turmeric and curcumin aren’t toxic to humans. However, this might be because curcumin is so poorly absorbed.
But adding compounds like piperine makes curcumin much easier to absorb, and this might increase the risk of liver injury.
However, millions of people take turmeric supplements every day without problems, so there must be more behind the liver damage.
In short, scientists don’t know yet. The authors of the Tuscany paper theorize that drug interactions might be part of the answer.
Others wonder whether a genetic component might make some people more susceptible to injury than others.
The authors of the DILIM review explain that 7 of the 10 patients did have a particular genetic variant.
Previous studies have shown that this variant is also associated with liver injury from other compounds, including green tea.
Still, identifying who is most at risk of liver injury from curcumin will take more research. And because this is such a rare issue, the details will be challenging to pin down.
Following a series of curcumin-related liver injuries in Italy, the Italian Ministry of Health took action in 2019.
They made this message mandatory on supplements containing turmeric: “In the event of alterations in liver function, biliary, or calculosis of the biliary tract, the use of this product is not recommended.”
Manufacturers also need to add: “If you are taking other pharmaceutical treatments, it is appropriate to seek the advice of a physician.”
In August 2023, following 18 reports of similar liver injuries in Australia, the country's Department of Health and Aged Care published a safety advisory stating:
“Consumers and health professionals are advised that medicines and herbal supplements containing the herb Curcuma longa (turmeric) and/or curcumin may cause liver injury in rare cases.”
Aren’t there more pressing concerns?
There certainly are greater risks to liver health than turmeric supplements — alcohol is an obvious frontrunner. The difference is that no one is promoting alcohol as a cure-all.
In the case of turmeric supplements, despite minimal evidence, manufacturers market these products with claims of health benefits.
The authors of the Tuscany paper describe some of the many lab and animal studies on turmeric.
This research suggests that curcumin may have antioxidant, anticancer, anti-inflammatory, antimicrobial, and antiviral properties, as well as the potential to help lower blood sugar and heal wounds.
But the authors also observe that human studies haven’t shown clear benefits so far, which is why doctors don’t prescribe turmeric.
Plus, curcumin can affect many types of molecules, including proteins, enzymes, DNA, and RNA, making its possible health effects difficult to predict.
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What should you do?
We’ll end this article as we started it: You don’t need to worry about adding turmeric to meals or drinks.
Scientists have shown that it’s safe, and people worldwide consume this spice freely without issues.
If you take a turmeric supplement that includes piperine, you’re still very likely to be completely fine. These cases of liver damage are incredibly rare.
However, there’s no strong evidence that turmeric can benefit your health. So, you might consider swapping your supplement for a piece of fruit or vegetable — we know that eating more plants does support your health.
Acute liver injury following turmeric use in Tuscany: An analysis of the Italian Phytovigilance database and systematic review of case reports. British Journal of Clinical Pharmacology. (2020). https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/bcp.14460
Comparative absorption of curcumin formulations. Nutrition Journal. (2014). https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-13-11
HLA-B*35:01 and green tea-induced liver injury. Hepatology. (2021). https://pubmed.ncbi.nlm.nih.gov/32892374/
Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers. Planta Medica. (1998). https://pubmed.ncbi.nlm.nih.gov/9619120/
Liver injury associated with turmeric — a growing problem: Ten cases from the drug-induced liver injury network [DILIN]. The American Journal of Medicine. (2023). https://www.amjmed.com/article/S0002-9343(22)00740-9/fulltext
Medicines containing turmeric or curcumin — risk of liver injury. (2023). https://www.tga.gov.au/news/safety-alerts/medicines-containing-turmeric-or-curcumin-risk-liver-injury
Turmeric. (2020). https://www.nccih.nih.gov/health/turmeric