Liver Damage Caused by Supplements Is Becoming More Common

Wellness isn’t just a personal goal. It’s a burgeoning industry, with herbal and dietary supplements more popular and more plentiful than ever. As well, according to the Food and Drug Administration (FDA), compared to 30 years ago, the number of supplements on the market has increased dramatically. 

Herbal and dietary supplements are widely seen as “natural,” and that makes them safer than pharmaceuticals, many people believe—but that belief turns out to be highly questionable, says Dr. Robert Brown, Vincent Astor Distinguished Professor of Medicine, Chief of the Division of Gastroenterology and Hepatology and a leading liver transplantation physician.  

While supplement-related liver damage is rare, the problem has been growing for two reasons:  

Many people harbor fears of prescription medications—and some can indeed be unsafe in certain individuals. However, unlike supplements, pharmaceuticals have gone through rigorous clinical trials to confirm their safety and effectiveness. By contrast, supplements are largely unregulated and, as such, untested.  

Lack of regulation 

Herbal and dietary supplements don’t fall under the purview of the FDA. They’re considered “food,” and that means they aren’t subject to regulation in the way that pharmaceuticals, medical devices and even over-the-counter medications are. And that’s a problem, says Dr. Brown. 

“Many herbal and dietary supplements make claims in the media or on the internet that appear to be backed by research. But these claims are not fully scrutinized by the FDA or in the peer-reviewed literature,” he says.  

There are daily upper limits for nutrients, set by the Office of Dietary Supplements. These vary according to age and sex. But herbal supplements have no such limits, and the research remains scant. 

“Is the manufacturer trustworthy? How about those who sell the supplement? Is the supplement what they say it is?” These are rhetorical questions, but he advises all of us to ask them in earnest when considering taking a supplement. 

In other words, let the buyer beware. 

What does the liver actually do? 

According to the American Liver Foundation, the liver performs hundreds of functions. Many of these are related to metabolism: converting food to energy, producing the basic nutritional building blocks our bodies need and eliminating waste. 

But one of its functions is especially relevant to our topic. The liver filters our blood, removing the toxins found in medications as well as supplements and other potentially harmful substances. 

“If a bioactive substance is useful, it can also be harmful,” Dr. Brown explains. An antibiotic can be used to treat and cure a bacterial infection. It’s useful, in other words—but its side effects can be harmful. The same holds true for supplements. In fact, the liver damage caused by supplements is identical to the damage caused by pharmaceuticals and over-the-counter (OTC) medications.  

Why are some people more susceptible to liver injury than others? 

Sometimes, and in some people, the liver can become overwhelmed when the demands on its filtering and detoxifying functions become too great. 

Whether it’s a botanical like turmeric or ashwaganda, or an over-the-counter medication like acetaminophen (Tylenol)—a common cause of liver injury when taken in higher-than-recommended doses—the liver’s reactions vary from person to person. A growing field called pharmacogenomics aims to predict a person’s response to these substances, based on their genetic background.  

In members of the susceptible minority, even a small amount of a toxic substance can lead to liver overload. It’s comparable to an allergy, says Dr. Brown. Even a small amount of an allergen can create an outsize reaction in, say, a patient with a peanut allergy. Similarly, a capsule containing a small amount of turmeric, especially when taken over a long period of time, can wreak havoc with the liver in certain vulnerable individuals. 

Symptoms of liver injury 

During the early stage of liver damage, whatever the cause, there are no symptoms. The only way your doctor can tell what’s going on is by administering and monitoring blood tests. 

If a patient’s liver enzymes are elevated in successive blood tests, the following symptoms may soon make an appearance: 

And at a more advanced stage of liver injury, a patient may develop: 

…and more. 

Diagnosing and treating the problem 

Aided by further testing, specialists like Dr. Brown begin to rule out other possible causes of liver injury, including hepatitis (A, B or C), autoimmune disease, fatty liver disease or alcohol. If none of these turn out to be the culprit, a medication or supplement is the likely cause. And there’s a name for the condition: toxic hepatitis. 

Many herbal supplements are actually complex mixtures of ingredients. That makes it hard to tell which one is toxic. While the injury it causes can be severe, it can usually reversed by discontinuing the drug or the supplement.  

In rare instances, a liver transplant may be needed to resolve the problem. The good news is that liver transplantation is much more successful that it was in the past, especially at Weill Cornell Medicine—a leading center for organ transplantation.  

A great resource for doctors and patients alike 

The LiverTox database is a free tool that lists the medicines and supplements linked to liver injury. LiverTox is a great resource that provides comprehensive information on all commercially available drugs and supplements that have the potential to cause liver damage. Find it at LiverTox.nih.gov.