Liver failure due to dietary supplements: excessive doses may lead to serious and lasting health consequences

In recent years, the use of dietary supplements has become increasingly common among Slovenians, with many turning to vitamins, minerals, probiotics, and plant-based preparations as part of their daily routine. While some of these supplements can indeed be beneficial and even recommended in specific cases, reports have emerged highlighting serious health consequences associated with excessive consumption. According to data from the National Institute of Public Health (NIJZ), there have been instances of acute liver damage and kidney failure linked to improper intake of dietary supplements in Slovenia. These incidents underscore the potential risks that come with overuse or misuse of such products.

The issue of adverse effects from dietary supplements is not new, but the frequency and severity of reported cases have raised concerns. The system of monitoring adverse effects of food and dietary supplements—known as nutrivigilance—has been in place in Slovenia for ten years. Dr. Tanja Carli and Dr. Urška Blaznik from NIJZ explain that the most commonly reported issues include digestive problems, skin changes, and liver damage. More severe cases have included acute liver failure, acute kidney injury, and anaphylactic reactions. This year alone, cases of acute liver damage and severe allergic reactions have already been documented. Research conducted in the United States suggests that approximately one-fifth of all liver injuries are related to herbal and dietary supplements.

Despite the growing popularity of these products, experts emphasize that most healthy adults who maintain a balanced diet do not need additional supplementation. However, the perception that these products are entirely safe often leads to their misuse. Many individuals fail to recognize that long-term use of certain plant extracts may not be sufficiently studied, and some health issues, such as elevated liver enzymes, are only detected during preventive check-ups. Another significant concern is the simultaneous use of multiple supplements, which can lead to unintentional overdosing of the same nutrients. Professor Igor Pravst from the Institute of Nutrition highlights that a considerable number of people use several different products at once, increasing the risk of nutrient duplication without awareness.

Vitamin supplements, while generally considered harmless, can cause serious health problems when consumed in high doses. Experts at NIJZ warn that the risk is particularly high with multi-vitamin and mineral preparations, as they may contain similar vitamins and minerals. Special caution is needed with fat-soluble vitamins such as A, D, E, and K, which accumulate in the body. Excessive intake of vitamin A can result in liver damage, headaches, vision problems, and neurological issues. Even water-soluble vitamins carry risks; prolonged high-dose intake of vitamin B6 has been linked to peripheral nerve damage, while very high doses of vitamin B3 can elevate liver enzymes.

Dietary supplements can also interact with medications, posing additional risks. Particular care is required when taking blood thinners, post-transplant medications, antiepileptic drugs, and thyroid hormones. For example, iron supplements can reduce the absorption of levothyroxine. Despite these warnings, many individuals continue to use supplements based on beliefs rather than evidence, especially those marketed for detoxification, rapid weight loss, or immune support. Professor Pravst points out that the scientific basis for many such products remains weak, suggesting that success in marketing often overshadows actual medical necessity.

Experts recommend that individuals consult healthcare professionals before starting any supplement regimen, especially if they are using multiple products simultaneously. The NIJZ advises that supplements should only be used when there is a clear medical indication, such as vitamin D deficiency during winter months, folic acid for women planning pregnancy, or vitamin B12 for vegetarians. Even in these cases, supplementation should be guided by professional advice to ensure safety and effectiveness. As the use of dietary supplements continues to rise, it becomes increasingly important to balance consumer demand with scientific evidence and regulatory oversight to mitigate potential health risks.