Nutrition and supplements to “boost” the immune system?

A no B.S. guide to a good immune system.

We are living in crazy coronavirus times, in which we notice a lot of messages circulating on social media around supplements and specific diets that seemingly “boost” the immune system. Your immune system often defends very well against pathogenic micro-organisms, but sometimes it fails: a germ successfully penetrates and makes you sick. Is it possible to intervene in this process and to strengthening your immune system? What if you improve your diet? Or take certain vitamins or herbal preparations?


“Boost” the immune system?

The immune system is a complex system and not a separate entity. The idea that you can strengthen the immune system or can “boost” it sounds tempting, but in reality, it’s not that simple. There’s still a lot that researchers need to uncover around the intricacies and interconnectedness of the immune system. What is known is that the body continuously produces immune cells. Nobody knows how many cells, or which mix of cells the immune system needs to function optimally. Attempting to “boost” the cells of the immune system is very complicated, because there are so many different types of cells in the immune system that respond to so many different microbes in so many different ways. To “quickly boost” the immune system with, e.g. specific high-dose supplements, juices or a special tea is not possible, because it’s not that simple. Your immune system is affected by hundreds of factors, and it also needs time to adjust accordingly.
Now we are dealing with the coronavirus. The coronavirus is new, which means that no one has built up immunity against this disease. The virus is very contagious and can spread easily. You can (to a certain extent) work with nutrition and lifestyle strategies to maintain a powerful immune system. The fact is, that the majority of the population does not meet the recommendations regarding nutrition and exercise. So, there is certainly something WE can do. 


Healthy people

Healthy people have a healthy immune system. A healthy lifestyle gives the immune system everything it needs to do its job. Sometimes one healthy person is more sensitive for infections than another healthy person. The immune system may also be influenced by genetic predisposition, what we eat, the amount of exercise and our sleeping patterns. Good personal hygiene is also important.


Your diet and our immune system.

If you compare the immune system to an army, you can imagine that every soldier must be fed well and regularly in order to function optimally. What you want to prevent is a deficit of healthy food and therefore a deficiency of vitamins and minerals. This also means no crash diets or leaving out entire food groups. For example, we have read a few things about people thinking that ketosis (a process in which you burn fatty acids for energy, because you omit carbohydrates from the diet) is “the way to go” during an epidemic. We do not recommend this. By omitting such a complete food group, you avoid fruits, whole wheat grains, legumes, and certain vegetables. This puts you at great risk of a deficiency in B vitamins, vitamin C, iron, zinc, magnesium and folic acid, among others. A deficit is the last thing what you want to cause.  


Losing weight and your immune system

If you’re losing weight, make sure that you get enough protein, vitamins and minerals. You are more susceptible to infections. Extra protein, lots of vegetables, fruit, whole grains, and possibly an additional multivitamin supplement is a wise way to support your reduced food intake.


Body exercise

Sitting still is bad for your immune system. So, exercise is important! If you exercise (moderately intensive), the amount of T cells and NK cells in your body increases. These are immune cells. Being active also promotes good blood circulation, allowing the cells and substances of the immune system to move freely through the body and do their work efficiently. Avoid very long training sessions (longer than two hours) and, long periods of intensive training, as this can affect the immune system. If you still want to plan a long training session (>90 minutes, moderate-highly intensive), make sure you have enough carbohydrates before and during the exercise. Before exercising you can think of 2 pieces of fruit and during exercise you could think of a 500ml isotonic sports drink per hour. This way you reduce the amount of stress hormones and, thus support your immune system.


Sleep pattern

Too little sleep can affect the immune system. Not sleeping one night does not necessarily have a direct impact on the immune system, but if you ensure a long sleep deprivation, this may end up affecting it. Sleep at least 7 hours per night. Sleep quality is also important (e.g. waking up/not waking up frequently during the night).



Unfortunately, extra (highly-dosed) vitamins do not give an acute better immune system Everyone tries to defend themselves against the coronavirus and in this hides the danger of getting wrong advice from people on social media or entrepreneurs who respond to the fear of the virus with so-called "immune system boosters". If you eat a healthy, balanced diet, you get everything you need from your diet. For some groups, the advice is to take specific vitamins extra.

  • Vitamin C
    It is not necessary to take an extra vitamin C supplement. Vitamin C is necessary to maintain a good immune system and it is an antioxidant, but is not a miracle cure in itself. Your body needs áll the nutrients to function optimally, not just 1. We also advise against gigantic doses of vitamin C. Your body only absorbs what it needs. Increase your fruit and vegetable intake to reach your recommended daily allowance. Vitamin C is found in fruit (think of blueberries, strawberries, kiwi and citrus fruits), vegetables and potatoes.
  • Vitamin D
    Vitamin D plays an important role in the proper functioning of the immune system. It is also necessary for calcium absorption and proper muscle function.There is a supplement advice for vitamin D of 10-25 micrograms per day for anyone with a toned skin colour, anyone over 50 and pregnant women. But now that we are more indoors and autumn/winter has passed, this advice may apply to all. We don’t get much sun now and an important source of vitamin D is, you guessed it, the sun. A surplus of vitamin D can only occur with long-term excess of vitamin D in the form of a supplement.
  • Vitamin B12
    Vitamin B12 is necessary for the production of red blood cells that are required to carry oxygen in the blood. B12 is also important for the proper functioning of the nervous system. For vegans, the advice is to take a vitamin B12 supplement. The advice is to take 1000 µg 2-4x per week or 250 µg with daily use.
  • Omega 3
    Omega 3 is important for the brain and protects against cardiovascular disease. For people who don’t eat fish, omega 3 supplements are an alternative. Fish get the omega 3 fatty acids from the algae they eat. Omega 3 can therefore also be obtained directly from algae. Omega 3 can also be found in, e.g. nuts such as walnuts, chia seeds, broken flax seeds, pumpkin seeds and halvarines/margarines with added omega 3.
  • Iron
    Iron is important, among others, for the formation of haemoglobin, which is a part of red blood cells. These carry oxygen throughout the body. People at risk of iron deficiency are women of childbearing age, pregnant women, breastfeeding women, vegetarians, vegans and athletes who exercise intensively. Iron can be found in legumes (e.g. tofu and beans), nuts, cereal products (e.g. whole wheat bread and whole wheat pasta) and vegetables (e.g. spinach and kale). Are you unsure whether you have an iron deficiency? A blood test can give more insight. A supplement may provide support.
  • Zinc
    Zinc is necessary for building proteins, DNA and for the proper functioning of the immune system. Zinc is found in small amounts in many different foods, including nuts and cereal products (e.g. oatmeal, rye bread, brown rice and whole wheat bread). A deficiency can arise if you do not consume enough of these products or in people with malfunctioning intestines. Vegetarians and vegans are at risk of a reduced intake from a regular food.
  • Magnesium
    Magnesium is important for the proper function and formation of muscles and is found in many products, e.g. cereal products (think whole wheat pasta and whole wheat bread), vegetables (e.g. spinach) and nuts. A deficit can arise if you do not consume enough of these products. A magnesium deficiency is uncommon (only with, e.g. malfunctioning kidneys or intestines). An excess is only possible when using supplements.
  • Multivitamins
    Extra vitamins and minerals can never completely replace real products like fresh fruit and vegetables. Vegetables and fruit offer more substances than just vitamins and minerals that reduce the risk of diseases. If you want to get more vitamins and minerals, make sure you have more healthy food. If you prefer to opt for extra multivitamin, e.g. because you have been losing weight for a long time or because you do not have enough options for a healthy diet, take a multivitamin with no more than 100% DV (this advice does not apply to vitamin B12, because B12 from a supplement form is poorly absorbed (see he advice for B12)).
  • Other supplements and herbs
    There are currently no supplements that have scientifically proven to have an effect on “boosting” the immune system. Be careful when using extra vitamins, minerals and herbal remedies in the form of a supplement. Some vitamins can become toxic above a certain amount. Some herbal remedies can interact with medications. Also keep in mind that some of these “medicinal herbs” are not properly regulated, so you can’t assume they are safe. Some plant supplements do no harm (if used with common sense and therefore not used more than recommended), but they will not support if the body does not get enough energy, vitamins and minerals from regular foods.
  • Colloidal silver (water)
    We advise against it. It can cause serious side effects and can be dangerous to health. Read more about this here:

Conclusion: How do you maintain your strong immune functions?

You can certainly do something to maintain a strong immune system. We have a list that you can check off:

  • Prevent a (large) deficit of calories;
  • Prevent a deficit of proteins;
  • Prevent a vitamin and mineral deficiency (supplement with specific vitamins/minerals if necessary, but avoid highly-dosed vitamins and minerals);
  • Eat a lot of vegetables: at least 250 g per day (more is better);
  • Eat a lot of fruit: at least 2 servings of fruit per day (more is better);
  • Choose whole grains, such as whole wheat bread, whole wheat pasta, whole wheat wraps, brown rice and oatmeal;
  • Vary with lentils, chickpeas, beans, tofu, tempeh, seitan and other plant-based protein rich products;
  • Eat 15-25 g unsalted nuts daily;
  • Drink enough fluids, such as water, tea and coffee;
  • Get enough (good quality) sleep;
  • Exercise daily for at least 30 minutes. In addition, do muscle strengthening exercises at least twice a week;
  • Preferably no alcohol;
  • No diets with very little calories per day or diets where food groups are omitted (e.g. low-carb);
  • Some plant supplements do no harm in healthy individuals (if not used more than is recommended). Keep in mind that supplements do not support if the body does not get enough energy, vitamins and minerals from regular foods;
  • Do you have an underlying disease? Always discuss supplement use with your physician and have your diet analysed by a dietitian;
  • Ensure good hygiene. Wash your hands several times a day for at least 20 seconds and use soap. Do you use disinfectant gel or disinfectant wipes? Use one that contains at least >60% alcohol;
  • Be informed about covid-19 using international and national organizations such as the WHO and RIVM;
  • Are you unsure whether you are getting enough? Have your nutrition analysed by a (sports)dietitian.

Stay safe and healthy!