Vitamin C, vitamin D, and zinc contribute to the normal function of the immune system — these are approved EU health claims. They're complemented by selenium, iron, vitamin A, copper, folate, and B6 and B12, which all support the same defense function. The most reliable foundation remains a healthy lifestyle.
Supporting your immune system – the short answer: Several nutrients contribute to the normal function of the immune system – above all vitamin C, vitamin D and zinc. These contributions are officially approved as EU health claims and refer to the normal function of the body's own defences, not to preventing or treating colds. The most solid foundation remains your lifestyle: sleep, nutrition, exercise and stress management.
It's November, it gets dark early, and you hear the first coughs in the office – and suddenly all eyes turn to the "immune defences". This is exactly the situation in which many people reach for vitamin C, D and zinc. Here we take an honest and confident look at what these three are actually allowed to do in the body (and what they are not).
The key points at a glance
- Several nutrients contribute to the normal function of the immune system – above all vitamin C, vitamin D and zinc.
- Selenium, iron, vitamin A, copper, folate as well as vitamins B6 and B12 also belong to this group.
- The foundation remains your lifestyle: sleep, nutrition, exercise, stress management.
- With vitamin D in particular, it's worth checking your levels in winter – ideally via a blood test.
How nutrients support the body's own defences
The immune system is one of the most complex networks in the body – an interplay of white blood cells, messenger substances, mucous membranes acting as a barrier and many metabolic processes. For this network to work normally, it needs a good supply of nutrients. For several vitamins and trace elements, the contribution to the normal function of the immune system is officially recognised in the EU. Important for context: this is about the normal function – not about preventing or treating illnesses.
Vitamin C: the best-known immune nutrient
Vitamin C is water-soluble, is barely stored in the body and therefore needs to be supplied regularly. In the body it acts, among other things, as an antioxidant and is involved in many enzymatic processes. The approved statements are strong: vitamin C contributes to the normal function of the immune system, it contributes to the reduction of tiredness and fatigue and helps to protect cells from oxidative stress. Good sources are bell peppers, berries, citrus fruits and cabbage. You'll find suitable products in the Vitamin C category, and background information in Vitamin C: Effects & Daily Requirement.
Vitamin D: the winter candidate
Vitamin D plays a special role, because the body produces it via sunlight in the skin. From October to March, however, the sun is so low in our latitudes that the body's own production drops sharply – which is exactly why supply is often a topic during the winter months. Approved is: vitamin D contributes to the normal function of the immune system. Why it is often combined with K2 is explained in Vitamin D3 + K2; how to assess your requirement is shown in Vitamin D: Dosage Based on Blood Level. Products in the Vitamin D category.
Zinc: the underrated trace element
Zinc is involved in countless enzymatic reactions and is of central importance for immune cells. Approved is: zinc contributes to the normal function of the immune system and helps to protect cells from oxidative stress. It is found in wholegrain products, pulses, pumpkin seeds and cheese, among others. More in Zinc: Effects & Daily Requirement and in the Zinc category.
The approved immune claims at a glance
| Nutrient | Approved statement (in essence) | Example foods |
|---|---|---|
| Vitamin C | contributes to normal immune function | Bell peppers, berries, citrus fruits |
| Vitamin D | contributes to normal immune function | Oily fish, eggs, sunlight |
| Zinc | contributes to normal immune function | Pumpkin seeds, wholegrains, cheese |
| Selenium | contributes to normal immune function | Brazil nuts, fish, eggs |
| Vitamin A | contributes to normal immune function | Liver, carrots, egg |
| Iron | contributes to normal immune function | Pulses, meat, oats |
| Copper | contributes to normal immune function | Nuts, wholegrains, cocoa |
| Vitamin B6 / B12 / Folate | contribute to normal immune function | Meat, fish, green vegetables |
Further immune nutrients
So, alongside the "big three", other nutrients also contribute to a normal function of the immune system: selenium, iron, vitamin A, copper as well as vitamins B6, B12 and folate. A varied diet covers a lot of this; targeted supplementation can be useful when needs are increased. A broad overview is provided by Nutrients for the Immune System at a Glance and the Immune System category.
What research is investigating about the immune system
The immune system is a perennial topic in nutritional research. What is investigated above all is how individual nutrients are integrated into the function of immune cells – such as zinc as a component of numerous enzymes or vitamin C in its role as an antioxidant. A particularly active field is the vitamin D supply during the winter months, because the body's own production naturally declines then. In all honesty, it should be noted: the approved statements refer to the normal function – not to preventing infections. Much of what circulates beyond that is a research hypothesis, not a proven effect.
The underrated factor: your lifestyle
No supplement replaces the basics. The four biggest levers lie in your everyday life:
- Sleep: restful sleep is central – tips in Sleeping Better Naturally.
- Nutrition: plenty of vegetables, fruit, fibre and colourful variety.
- Exercise in the fresh air – which at the same time provides daylight for vitamin D production.
- Reduce stress and drink enough fluids.
How to specifically support your immune system through the cold season is covered in Strengthening the Immune System in Winter and Building Up the Immune System in Autumn.
Combining vitamin C, D and zinc cleverly
The three can be used well together, but each makes the most sense at its own particular time. Vitamin C is water-soluble and is best used when spread throughout the day – two small portions beat one large one. Vitamin D is fat-soluble and therefore goes well with a meal containing some fat. Zinc is not well tolerated by some people on an empty stomach, which is why taking it with a meal is often more comfortable. Anyone taking several supplements in parallel is best keeping an eye on the total amount – how to manage this is shown in Combining Supplements Correctly. One detail on the side: zinc and copper stand in a certain relationship to each other, which can play a role with prolonged, high zinc intake.
What to keep in mind for your supply
- Need rather than a scattergun approach: supplement specifically what is lacking – with vitamin D, a medical test is worthwhile.
- Choose well-available forms and a clear dosage.
- Prefer pure, lab-tested products made in Germany.
An honest assessment
What is proven and approved in the EU is that the nutrients mentioned contribute to the normal function of the immune system. What is not permitted – and also not serious – is the promise that a supplement prevents or cures a cold. Supplements are one building block, not a protective shield. If there is a concrete suspicion of a deficiency or persistent symptoms, please have it checked medically, especially your vitamin D status.
Suitable products & further guides
Categories: Vitamin C, Vitamin D, Zinc and the collective section Immune System. If you want to be broadly covered, the Multivitamin category offers combinations.
Further reading: Vitamin C: Effects & Daily Requirement, Vitamin D Based on Blood Level, Zinc: Effects & Daily Requirement, Nutrients for the Immune System, Strengthening the Immune System in Winter and Sleeping Better Naturally.
Frequently Asked Questions (FAQ)
Which nutrients are most important for the immune system?
The best known are vitamin C, vitamin D and zinc – for all three the contribution to normal immune function is approved in the EU. In addition, selenium, iron, vitamin A, copper as well as vitamins B6, B12 and folate also contribute. A varied diet covers a lot; targeted supplementation is done according to need.
Can vitamin C, D or zinc prevent a cold?
No. The approved statements refer to the normal function of the immune system, not to preventing or curing colds. Nutrients are one building block of a healthy supply – not a protective shield and no substitute for medical advice.
Why is vitamin D a topic in winter?
The body produces vitamin D via sunlight in the skin. From October to March, the sun is so low in our latitudes that this production drops sharply. That's why it's worth checking your supply, especially during the winter months – ideally via a blood level determined by a doctor.
Is a multivitamin enough for the immune system?
A multivitamin can provide a broad basic supply, but replaces neither a balanced diet nor a healthy lifestyle with sleep, exercise and stress management. Whether a combined supplement or targeted single supplements make more sense depends on your individual needs.
Health notice: This guide is for general information purposes only and does not replace individual medical or pharmaceutical advice. Food supplements are not a substitute for a balanced, varied diet and a healthy lifestyle. If you have health concerns, are pregnant or breastfeeding, or are taking medication, please consult a doctor or pharmacist. How our guides are created →
Sources
- Vitamin D | DGE — German Nutrition Society (DGE)
- Reference Value Zinc | DGE — German Nutrition Society (DGE)
- Vitamin C – Surprisingly Healthy? — Verbraucherzentrale (German Consumer Advice Center), 2025
- More Zinc for Colds? — Verbraucherzentrale (German Consumer Advice Center)
- Maximum levels for vitamins and minerals in food supplements and fortified foods — German Federal Institute for Risk Assessment (BfR), 2021
