Turmeric has a long history of use as a traditional medicine and food ingredient. The turmeric you buy is the spice made by drying and grinding the root of the turmeric Turmeric is long plant. Curcumin is one of the natural chemical components in turmeric and is considered one of the ingredients with medicinal benefits and effects. Turmeric sales have grown in recent years and it is now one of the top selling natural products in the US. It is also under increasing scrutiny from researchers and regulators as serious reports of liver damage related to consumption become more common.
Clinical trials of turmeric have been unimpressive from an efficacy point of view. There is some suggestion of benefit for conditions such as osteoarthritis of the knee, mucositis, high triglycerides or allergic rhinitis, but no convincing evidence of routine medical use has been established. The biggest challenge in using curcumin as a medicine seems to be that the chemical is poorly absorbed. Manufacturers have come up with different formulations (e.g. nanoparticles, liposomes) which complicate the interpretation of each study. Doses vary widely from 100 mg to several grams per day, and formulations include tablets, liquids, and root extracts. The poor absorption may also be responsible for the safety profile, which is generally considered safe orally, even at daily doses measured in grams when used for several weeks. However, some turmeric supplements are now marketed as being combined with black pepper, which significantly improves its absorption. (If you haven’t seen the Marc Maron piece on turmeric and black pepper, it’s pretty funny.) Piperine, a component of black pepper, appears to inhibit glucuronidation (a metabolic process) in both the gut and liver. Inhibition increases the amount of curcumin available to the body. Consequently, the potential risk of unwanted or harmful effects is also increased. Other means have also been developed to increase absorption, such as nanoparticles.
Due to better absorption, higher (effective) doses seem to result in more cases of liver damage. Cases have occurred weeks to months after routine intake begins – reported to begin with fatigue, nausea and poor appetite, followed by dark urine and jaundice. Recovery is usually rapid when turmeric consumption is discontinued.
A recent article published in the American journal of medicine describes ten cases of liver damage associated with turmeric. Founded in 2003 as a collaborative agreement between academic centers, the Drug-Induced Liver Injury Network (DILIN) studies liver-related injuries associated with drugs, as well as herbal products and other nutritional supplements. This article reviewed all cases between 2004 and 2022 in which turmeric was cited as a cause. Causality was assessed and the available product was analyzed for the presence of turmeric. Ten cases of turmeric injury were reported, all since 2011, six since 2017. Five of the ten were hospitalized and one patient died of acute liver failure. Chemical analysis confirmed turmeric in all seven available products tested. Three products also contain piperine.
Genetics may also play a role in some individuals being at higher risk of liver damage from turmeric. Seven cases were found carrying the HLA-B*35:01 allele which has already been implicated as a potential biomarker predicting liver injury from other products such as green tea and Polygon multiflorum, a Chinese herbal medicine. It is also associated with the risk of injury from regular medications. This allele is carried by 5-15% of the US population.
Based on concerns about health claims related to turmeric and the potential but rare risk of serious harm, Italy recently banned health claims related to turmeric and placed a warning on products derived from Turmeric is long carrot. This followed reports of about 20 cases of liver damage in the country attributed to use:
IMPORTANT WARNING In case of hepatic, biliary or calculosis abnormalities in the bile ducts, the use of the product is not recommended. Do not use during pregnancy and lactation. Do not use for long periods without consulting your doctor. If you are taking any medications, it is advisable to hear the doctor’s opinion.
Bottom Line: Turmeric has rare but serious risks
Turmeric supplements have medicinal promise, but their role is not well established. The combination of turmeric with black pepper has been shown to increase the absorption of the drug. Liver damage is a rare but apparently real risk of consumption. If consumption as a supplement is considered, use with or without piperine should be kept consistent. Research on genetic risk factors for liver damage from supplements such as turmeric is still preliminary, but has the potential to identify those at greater risk of damage. Until then, whether it’s turmeric or another dietary supplement, it’s important to monitor carefully for signs and symptoms of liver damage or other damage.