Can Dietary Supplements Cause Liver Damage?

Though many people don’t realize it, the answer to that question is a clear yes. A Keck Medicine of USC hepatologist advises. 

Many people take dietary supplements for a health boost. Some don’t realize, however, that there are times when supplements can do more harm than good. 

“So many dietary supplements have been linked to causing acute liver injury or even acute liver failure that leads to the need for an organ transplant,” says Lily Dara, MD, a hepatologist with the USC Digestive Health Institute, part of Keck Medicine of USC, an expert on hepatotoxicity who specializes in the clinical treatment and research of rare and complex liver diseases, including autoimmune liver diseases. 

It’s not that dietary supplements will harm everyone’s liver, Dr. Dara says. It really depends on the supplement, the person’s genetics and the dose and amount of the supplement. Many people can take supplements without an adverse effect.  

But if you have a certain genetic predisposition, supplements could put your liver at increased risk. Unfortunately, even though we have identified various genetic risk factors, the issue is complex, and many factors can contribute. Medical science cannot yet conclusively determine who will and who won’t experience a liver injury from supplements. 

Also, not all dietary supplements carry the same risk of liver injury or failure. Many supplements — such as calcium, collagen, fish oil, iron, milk thistle and multivitamins — are safe and rarely associated with liver injury. Others, however, do carry some risk, says Dr. Dara, who treats patients at Keck Hospital of USC, USC Norris Cancer Hospital and Keck Medicine of USC’s new Pasadena location at 590 S. Fair Oaks Ave. 

To learn about specific supplements’ association with liver damage, Dr. Dara advises visiting the National Institutes of Health resource LiverTox. Another free online resource, the Drug-Induced Liver Injury Network (DILIN), collects and analyzes cases of severe liver injury caused not only by herbal products and supplements but also prescription and over-the-counter drugs. 

Which of the more common dietary supplements can harm the liver? 

Be wary of supplements such as green tea extract (EGCG), turmeric (curcumin) and ashwagandha, Dr. Dara says. Natural food-grade products such as ground turmeric or turmeric root in food are perfectly safe when consumed in small amounts. In the commercial supplement form, however, these substances are frequently formulated at high doses and undergo industrial modification, including combination with other compounds to improve absorption, before being sold as capsules. 

“That’s not a natural product anymore because it’s been modified,” Dr. Dara says. 

Another important point: A medicine gets approved by the FDA only after a rigorous process involving clinical trials that show it’s effective and safe and that its benefits greatly outweigh its risks. But even though some herbal supplements have medicinal properties, the FDA regulates supplements as food, so manufacturers don’t have to demonstrate their products’ efficacy beforehand, Dr. Dara says.  

Dietary supplements often include numerous ingredients and exhibit variability across batches and lots. Because they are rarely studied in double-blind, placebo-controlled trials, their efficacy and their safe upper-dosing limits are often undefined, despite the fact that many contain potent bioactive compounds. 

“Many supplements promise more than they prove — so while the benefits are in most cases theoretical, the risks are undeniably real,” Dr. Dara says. 

How do I know which supplements are safe to take? 

In addition to consulting LiverTox, individuals should follow a general rule of thumb, Dr. Dara says: “I tell my patients, ‘Don’t take it unless your doctor prescribed it to you.’” 

If your doctor prescribes certain supplements to you, take them. Your doctor might want you to take vitamin B12 if you’re vegan, for instance. But in general, if you eat fruits and vegetables, you get all the vitamins you need. 

“Run everything by your doctor,” Dr. Dara says. “And if you have liver disease, definitely don’t take anything unless your doctor explicitly approves it. That’s because most things are metabolized by the liver, and you don’t want to cause more damage to your liver.” 

What is the potential liver damage that supplements can cause? 

Patients who experience liver damage from supplements might develop cholestatic liver injury (caused by slowed or stalled bile) or inflammation of the liver called hepatitis. Also, be on the lookout for signs of jaundice, Dr. Dara cautions. “If your eyes turn yellow while you’re using herbal dietary supplements, that’s very serious,” she warns. 

Other potential symptoms could start off seeming nonspecific, such as not feeling well, feeling nauseous, a change in bowel habits or having abdominal cramps. 

If any adverse signs appear, the first course of action is to stop taking the supplements. Some patients might need a liver biopsy for diagnosis. And in rare cases when the supplement induces an autoimmune liver injury, patients might need steroids to try to help suppress inflammation and the immune-mediated destruction of liver cells. 

Even more serious, some patients might experience liver failure from dietary supplements and then need a liver transplant. A liver specialist will determine when and if a transplant is needed. 

The bottom line? If you’re thinking about adding a certain dietary supplement to your daily regimen, it’s wise to check with your doctor before you start. By doing so, you can avoid taking a supplement that could interfere with your overall goal of enhanced wellness. 

Also, Dr. Dara adds, “Before turning to supplements, ensure you are getting adequate nutrients from the foods you eat daily. Include more vegetables and whole foods. Prioritize eating an orange instead of only taking a vitamin C supplement.” 

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Novid Parsi

Novid Parsi is a freelance writer with Keck Medicine of USC.

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