6 Unexpected Supplements That May Actually Be Leading To Kidney & Liver Damage, According To Experts: Green Tea Extract & More

When it comes to maintaining optimal health, supplements can often be a great addition to your diet. However, it’s important to exercise caution; some supplements may pose significant risks. While supplements are often marketed as natural and beneficial, excessive or improper use can lead to serious health consequences. This is oftentimes especially true when it comes to the health of your liver and kidneys.

To shed light on a few options that could be dangerous, we spoke to Dr. Kubanych Takyrbashev, MD, Health & Wellness Advisor at NAO; physician Dr. Erik Natkin; and Jesse Feder, RDN. These experts shared six potentially harmful supplements to be careful with. Find all of their warnings below.

1. Green Tea Supplements

Green tea extract, known for its high concentration of epigallocatechin gallate (EGCG) and weight loss benefits, can be harmful in large doses. Dr. Natkin warns that "case studies have linked excessive green tea extract ingestion to liver toxicity and acute liver failure." The liver damage is usually a result of the body's adverse reaction to high levels of catechins, which can cause oxidative stress and inflammation in liver cells. Stick to cups of green tea instead!

2. Kava

Kava is a popular anti-stress supplement that many people consume in order to bring a sense of calm to their brain and body. "Kava, which is typically consumed as a tea, is a supplement known to promote relaxation," Feder explains. Unfortunately, though, this relaxation could come with a risk; "Consuming kava regularly has been shown to affect enzyme and antioxidant activity in the liver which can lead to liver damage." Yikes! On top of this, kava could also pose a risk to your kidneys. "Kava may decrease blood flow to the kidneys and cause increases in harmful metabolites which can also damage them," Feder warns. Like any other supplement, you should always stick to recommended doses when consuming kava. Additionally, it's important to choose high-quality, reputable brands to ensure your safety.

3. Black Cohosh

Black Cohosh is another supplement that has been associated with liver damage. According to Dr. Natkin, "Black Cohosh has been linked to multiple cases of liver damage, particularly in people with existing liver disease or those taking other hepatotoxic medications." This makes it a risky choice, especially for individuals already managing liver health issues.

4. Comfrey

Comfrey contains pyrrolizidine alkaloids, which can be highly toxic to the liver. Dr. Erik Natkin points out that "comfrey can cause liver inflammation and veno-occlusive disease," a condition where veins in the liver become blocked. Both the FDA and the European Medicines Agency (EMA) have issued warnings about the hepatotoxic potential of comfrey, urging consumers to avoid it, he says.

5. Colloidal Silver

Despite being touted for its antibacterial and antiviral properties, colloidal silver supplements, which are liquids containing silver, can be harmful. Dr. Takyrbashev explains, "colloidal silver ingestion can result in silver particle accumulation in tissues, including the kidneys," leading to argyria, a condition where the skin turns bluish-gray. More concerning is the potential kidney damage from silver particles, which can impair the kidneys' ability to filter toxins and waste from the bloodstream.

6. Senna

Senna is commonly used as a natural remedy for constipation because it stimulates the muscles of the colon. However, Dr. Takyrbashev warns that "prolonged or excessive use of Senna can deplete the body of fluids and vital electrolytes." This can lead to dehydration and electrolyte imbalances, placing significant strain on the kidneys. Chronic dehydration and imbalances can ultimately damage the kidneys or worsen existing kidney conditions.