HEALTH

Which supplements are worth taking, which are not?

Dr Peter Gartner, medical director of Park Igls, reflects on the role and relevance of supplements.

They are on everyone’s lips, quite literally:

Supplements

Since the Nobel Prize–winning chemist Linus Pauling popularised high-dose vitamin C intake in the late 1960s as a means of preventing various diseases, particularly cancer, supplements have seen a remarkable rise in popularity. Today, in more than 75 percent of German households, opened boxes, bottles and blister packs with promising contents in all colours, shapes, flavours and forms can be found in medicine cabinets, bedside tables or miscellaneous drawers. In my practice, it is not uncommon for patients – particularly male patients – to bring bags or boxes filled with supplements to their first consultation and lay them out on my desk.

Due to their unrestricted availability in pharmacies, drugstores, supermarkets and even petrol stations, and particularly through online distribution, not least via »recommendations« from allegedly health-infused influencers and even fitness apps, access to supplements has become extremely low-threshold.

Which supplements are worth taking, who benefits from them, and what should you consider?

The vitamin and mineral market has grown strongly worldwide, not least due to the pandemic. Global turnover for 2025 is estimated by Hamburg-based Statista GmbH, which provides insights and data from 170 industries in more than 150 countries, at almost 30 billion euros, and continues to rise. How can this success be explained?

On the one hand, it is driven by (mostly exaggerated) consumers' expectations, who hope for improved performance, better regeneration, protection against disease, pain reduction, better sleep or simply a longer life. The question of which supplements are worth taking is often answered too quickly and in a generalised way. Too often, a supposed miracle substance is expected to compensate for the harmful effects of an excessive and sedentary lifestyle.

On the other hand, thousands of physicians facing diagnostic and therapeutic uncertainty are, quite literally, relieved to be able to »satisfy« supplement-seeking patients with placebo-like treatments. Supplements sound modern, are expensive and therefore must be effective – and if even the doctor takes them, as he claims, they surely cannot do any harm.

The success of supplementation has now developed to such an extent that a distinct group within the medical profession has emerged whose apparent purpose is to perform countless expensive laboratory tests to then prescribe – and directly sell – supplements based on those results. This group of so-called functional doctors refers to itself as holistic – yet works in a highly selective way. Because measurements without anamnesis, promises of healing without physical examination, or diagnosis without further specialist evaluation are not sufficient. As the saying goes: »If you measure, you measure rubbish.«

Supplements usually contain essential micronutrients with nutritional relevance, such as minerals, vitamins and trace elements, as well as components of proteins and fats like amino acids or fatty acids – often in high concentrations. Legally, despite their form as capsules, tablets or drops, they are not considered medication but food.

Manufacturers are therefore not required to list possible side effects, contraindications or interactions with medications on the packaging, which often makes it resemble an illustrated advertising leaflet. Only a few consumers are aware that supposedly harmless supplements can not only influence blood and urine test results but also interact with numerous (real) medications.

Possible side effects:

Vitamin B7, also known as vitamin H or biotin, is widely used to strengthen hair and nails, but it can interfere with blood test results for thyroid and sex hormones, as well as troponin, an important marker for heart attacks
Preparations containing glucosamine and chondroitin, commonly used for joint complaints, can interfere with blood-thinning medication and affect glucose metabolism.
In cancer therapy with cytostatics, a high oxidative state within cancer cells is intended to destroy them. Concurrent intake of antioxidants such as vitamin C may reduce the effectiveness of the therapy.

Which supplements should you take, and when are they truly useful?

Anyone fortunate enough to maintain a healthy and varied diet, exercise regularly, appreciate the importance of chewing and salivation through annual Mayr cures, and receive adequate sun exposure generally does not need supplementation.

Dr Henning Sartor, scientific advisor to the International Society for Modern Mayr Medicine, puts it clearly: »Healthy food needs no supplement.« Provided, one might add, that one lives by the sea. In our latitudes, however, the situation is usually somewhat different:

A lack of sunlight, not least due to dermatologically recommended caution regarding skin cancer, has led to widespread vitamin D deficiency, which can only be compensated for through supplementation in the form of drops or capsules. Vitamin D improves bone density, optimises immune function and supports brain function, particularly mood and memory.
Certain omega-3 fatty acids, important for healthy blood vessels, are found mainly in sea fish and should therefore be supplemented at least by individuals with corresponding risk profiles.
A latent magnesium deficiency is common and can lead to increased muscle cramps. Fortunately, magnesium cannot be overdosed, as the body only absorbs what it needs; excess magnesium remains in the intestine, softens stool and may lead to diarrhoea.
In times of increased infection risk, zinc supplementation may also be useful for supporting the immune system.
Vitamin C intake can also be useful – though not in the dosage of 18 grams daily as practised by Linus Pauling, who exceeded the recommended intake by a factor of 160 and nevertheless died of cancer.

The question of which supplements are worth taking has no general answer, but can only be clarified on an individual basis through proper diagnostics.