Nahrungsergänzungsmittel: Dosierung, Risiken & Wann sie sinnvoll sind | Stern.de

Many dietary supplements are incorrectly dosed, potential side effects exist, and medical recommendations often differ from marketing claims. This raises critical questions about the safety and efficacy of these widely used products.

Frei verkäuflich heißt nicht sicher

Dietary supplements, or NEMs, often resemble and are packaged like medications, but are regulated under food law, not pharmaceutical law. This means their effects and side effects aren’t routinely checked. Instead of being approved like drugs, they are simply reported to the German Federal Institute for Risk Assessment (BVL). Companies or individuals can submit basic information – name, address, product name, ingredients, quantities, and a label – in a matter of minutes. There’s no verification of accuracy or proper dosage.

The BVL states that no testing or approval by an authority occurs before a supplement is first marketed. Regional food surveillance authorities conduct only sample checks. Consumer protection groups, scientists, and politicians have criticized this lax regulation for years, citing potential for abuse. Products with dangerous additives repeatedly enter the market. The Federation of German Consumer Organisations documents numerous violations each month, including carcinogenic substances, salmonella, lead, and inappropriate ingredients like sildenafil (“Viagra”) or the banned appetite suppressant sibutramine.

Die Dosis macht das Risiko

Two numbers are crucial for protecting against overdoses: the reference value from the German Nutrition Society (DGE), indicating adequate intake for a healthy person, and the maximum amount set by the Federal Institute for Risk Assessment (BfR), exceeding which could be harmful. While manufacturers should adhere to these limits, they aren’t legally obligated to do so. A 2020 study by the Pädagogische Hochschule Schwäbisch Gmünd found that over half of 106 supplements exceeded the recommended maximum for at least one nutrient, by as much as 700 percent. Multivitamin preparations were particularly problematic.

There is some hope on the horizon: the EU is expected to establish binding maximum levels for certain supplement ingredients this year, including selenium, vitamin B6, vitamin A/betacarotene, vitamin E, vitamin D, and iron. It’s also important to note that the actual content of a supplement can deviate by up to 50 percent from the stated amount on the packaging.

Erst mal beim Arzt abklaeren

Determining whether a vitamin pill is needed requires examination. Fatigue, muscle cramps, or hair loss don’t always indicate a deficiency, and an unsuspected deficiency may exist. People with obesity, for example, are more likely to be deficient in vitamin D, while those with pancreatic, liver, or gallbladder diseases may have difficulty absorbing certain vitamins. Individuals with Crohn’s disease or celiac disease are also prone to deficiencies.

A dietary record, physical examination, and tests can provide clarity. Depending on the nutrient, blood, urine, or tissue may be analyzed. Test results can be influenced by external factors; zinc levels are often lower during infection, while ferritin levels increase with a cold.

Patients should inform their doctors about any supplements they are taking, as biotin can interfere with lab tests, including those for heart attacks and thyroid function. Some supplements can also affect therapies; high-dose antioxidants may reduce the effectiveness of cancer treatment.

Wenn Nahrungsergänzungsmittel krank machen

In 2022, a dangerously ill baby was admitted to intensive care, as reported by the “Deutsches Ärzteblatt.” The infant had lost weight, experienced altered consciousness, was dehydrated, had calcified kidneys, and exhibited abnormal potassium and calcium levels. The parents had administered vitamin D drops in an 80-fold overdose for several months, based on friends’ advice. Here’s just one example of a larger problem.

“I often see blood values that are too high – almost always because patients are taking dietary supplements,” says nutritional medicine specialist Diana Rubin from Vivantes-Klinikum in Berlin. Patients with chronic illnesses are particularly susceptible to online advertising. “About half of the patients in our clinic have taken an excessive dose of a supplement,” says Bernhard Schieffer, who runs a Post-Covid outpatient clinic at the University Hospital of Gießen-Marburg. He notes liver and vascular damage caused by products like curcumin, folic acid, or resveratrol, as well as high blood fat levels from excessive fish oil consumption.

Cancer patients are also vulnerable, warns Jutta Hübner, an oncologist and expert in complementary cancer therapies at the University Hospital of Jena. She cautions against both side effects and interactions with cancer therapy. High doses of antioxidants like vitamin C can weaken the effectiveness of chemotherapy and radiation, potentially worsening a cancer prognosis. Hübner advises discussing alternative therapies with treating physicians.

Wann Ergänzungen wichtig sind

Infants require essential minerals, and vitamins. The Federal Health Bulletin identifies four “critical nutrients” often requiring supplementation: iodine for breastfeeding mothers or in complementary foods, vitamin D (about 12 micrograms daily) until the second summer, vitamin K in the first weeks of life, and fluoride as long as toothpaste isn’t used. Pregnant women should ideally take folic acid four weeks before conception, along with iodine and iron if deficient.

Older adults experience a decline in energy needs while maintaining the same nutrient requirements. Depending on lifestyle, they may lack vitamin B12, iron, calcium, and protein. Vitamin D is crucial for preventing bone loss, especially in nursing homes where seniors rarely get fresh air. Vegans need vitamin B12 and iodine in pill or powder form, as recommended by the DGE, and often don’t get enough calcium and vitamin D.

Frequently Asked Questions

Was sind Nahrungsergänzungsmittel?

Nahrungsergänzungsmittel, kurz NEM, sind Lebensmittel, keine Arzneimittel. Sie enthalten Vitamine, Mineralstoffe und andere Stoffe, die dazu dienen, die normale Ernährung zu ergänzen.

Werden Nahrungsergänzungsmittel geprüft?

Nein, vor dem Inverkehrbringen findet keine Prüfung oder Genehmigung durch eine Behörde statt. Sie werden lediglich beim Bundesinstitut für Verbraucherschutz und Lebensmittelsicherheit (BVL) gemeldet.

Kann man Nahrungsergänzungsmittel bedenkenlos einnehmen?

Nein, da die Dosierung oft nicht korrekt ist und Produkte mit gefährlichen Beimischungen auf den Markt kommen können. Es ist ratsam, vor der Einnahme einen Arzt zu konsultieren.

Given the potential risks and uncertainties surrounding dietary supplements, how carefully do you consider your nutritional needs and sources before adding a supplement to your routine?