Experts Warn of Liver and Kidney Risks from Popular Dietary Supplements
Dietary supplements such as vitamin D, magnesium, creatine, collagen, vitamin C, biotin, and herbal extracts have become common in the daily routines of millions worldwide. However, experts caution that these products, often perceived as natural and safe, can pose significant health risks, particularly to the liver and kidneys. A British consumer survey found that 76% of respondents regularly take at least one supplement, with nearly 20% consuming four or more daily. Medical professionals globally report rising cases of liver, kidney, and digestive system damage linked to supplement use, especially when multiple supplements are taken simultaneously or in high doses.
Professor Ziv Ben Ari, head of the Liver Excellence Center at Assuta Medical Center, highlights that about 20% of liver injuries attributed to medications are actually caused by dietary supplements and herbal remedies. The use of these products has surged as people seek to improve general health or address issues like fatigue, pain, weight loss, or immune support. Clinical dietitian Michal Sokman emphasizes that while supplements can correct nutritional deficiencies and treat certain conditions, uncontrolled use may lead to side effects, drug interactions, and organ damage. She stresses the importance of evidence-based, personalized supplementation under professional guidance.
Research published in the New England Journal of Medicine in 2015 reported approximately 23,000 annual emergency room visits and 2,000 hospitalizations in the U.S. due to supplement-related adverse effects. Weight loss, energy, and performance enhancers were common causes among young people, while older adults experienced complications from high doses of vitamins and minerals or improper use. Sokman notes that many begin supplements based on social media or peer recommendations without verifying actual need.
Concerns are especially high regarding weight loss supplements, energy boosters, bodybuilding products, and complex herbal mixtures, particularly those from unregulated sources. Contrary to popular belief, "natural" does not guarantee safety; plant-based substances can also cause harm. A 2024 study in JAMA Network Open identified several herbal supplements linked to liver injury, including high-dose green tea extract, curcumin, ashwagandha, Garcinia cambogia, red yeast rice, and black cohosh. The U.S. National Institutes of Health's LiverTox database documents numerous liver injury cases from supplements, often related to high doses or prolonged use.
Kidney damage is also a risk, with excessive vitamin D intake potentially causing high blood calcium levels and kidney injury. High doses of certain minerals or protein supplements may worsen kidney conditions in susceptible individuals. Additionally, some supplements have been found to contain undeclared pharmaceuticals, contaminants, or toxins, as they are regulated as food rather than drugs, lacking mandatory clinical trials for safety and efficacy.
A recent Nature Microbiology study questioned the consistency and scientific backing of probiotic supplements, revealing limited bacterial diversity and unclear health benefits. Combining multiple supplements can lead to excessive intake of vitamins and minerals, harmful interactions, and increased organ strain. For example, concurrent use of multivitamins and vitamin B6 can cause nerve damage, while iron, calcium, and magnesium may interfere with nutrient absorption. Fat-soluble vitamins (A, D, E, K) accumulate in the body and do not always require daily supplementation.
Interactions with medications are also critical; vitamin K can affect blood thinners, St. John's wort reduces effectiveness of various drugs, and ginkgo, ginseng, and garlic may increase bleeding risk. Therefore, patients should inform healthcare providers about all supplements they take.
Supplements are medically justified when a deficiency is confirmed by blood tests, during pregnancy or planning, restrictive diets, malabsorption conditions, certain medications, or post-surgical care. Special caution is advised for older adults, pregnant or breastfeeding women, children, and patients with liver, kidney, cardiovascular diseases, diabetes, or after bariatric surgery.
Users should seek medical advice if experiencing symptoms like unusual fatigue, persistent nausea or vomiting, unexplained abdominal pain, dark urine, jaundice, appetite loss, irregular heartbeat, dizziness, or severe weakness. Blood tests are crucial for personalized supplement recommendations rather than relying on marketing claims. A 2022 USPSTF review concluded that most healthy individuals do not benefit from vitamin or mineral supplements in preventing chronic diseases and should avoid beta-carotene and vitamin E due to potential harm.
Professor Ben Ari concludes that the benefits and risks must be carefully weighed, with professional consultation and adherence to recommended doses. Michal Sokman advises asking three key questions before starting or continuing supplements: Is there a proven need? Could it interact with medications or health conditions? Is the dosage appropriate? These considerations outweigh any packaging promises.
