Strong immune systems are never taken for granted – in fact, in the current climate, immunity and health are arguably more sought after than before. Our immune systems protect us from foreign bodies and harmful environmental factors. In order for them to perform at their best without problems, our immune systems need our support: with the right diet, restful sleep, little stress and proper hygiene.
The immune system works like a machine: it needs the right fuel and enough of it. It gets bogged down if it has to run at full speed all the time. Like a machine, you yourself can maintain your body’s defence regularly and contribute to an optimal and well-oiled immune system. By eating a healthy diet, organising your daily routine in a way that eliminates stress and gives you enough time to sleep, you create the necessary conditions for a healthy immune system.
Read on for cheap and cheerful insights into how you can promote your body’s defence system with the right nutrients and lifestyle changes.
What is the immune system?
Your immune system works with a range of different cells and chemical processes to protect you from pathogens.
The following table gives you a brief overview of the most important terms related to the immune system.
Table: The immune system at a glance
Proteins on the surface used by immune cells to recognise foreign bodies
Specific control of foreign bodies
Formation of antibodies and memory cells
B memory cells
Aggressive oxygen molecules that promote inflammation
Combat bacteria and allergies
B cells, T cells, natural killer cells, natural killer T cells
White blood cells – granulocytes, lymphocytes, monocytes
Monocytes, which are found in the tissue
Scavenger cells that digest pathogens
Natural killer cells
Detection of cancerous or virus-infected cells and initiation of cell death.
Natural killer T cells
Combination of T cells and natural killer cells
Digestion of pathogens by monocytes
Recognition of antigens
Organ behind the breastbone; production of immune cells
Strengthen your body’s defence
Your immune system needs strength, so that it can fight pathogens properly. It gets this from a healthy diet, sufficient exercise and rest.
If you lack important nutrients or are plagued by stress in everyday life, the immune function of your immune system decreases. Especially in children and the elderly, care must be taken to maintain a strong immune system. In childhood, the immune system is not yet mature; in old age, immune function decreases.[1, 2]
Did you know that the production of T cells decreases with age? Therefore, the number of infections may increase, especially in the respiratory tract.[1, 2]
How can I strengthen my immune system?
In order for your immune system to perform its defensive function optimally, you should ensure you optimise the following in your everyday life:[3, 4]
- Balanced diet (enough fruits and vegetables), avoid nutrient deficiencies (vitamins, minerals) and healthy body weight
- Regular exercise
- No smoking and limited or no alcohol consumption
- Limited stress and healthy sleeping pattern
- Preventive health and hygiene measures – disinfection, vaccination
Nutrition: immune system boosters
Without nutrients, nothing works in the body, and, of course, this also applies to the immune system. Carbohydrates, fats and proteins provide the body with an energy source. Vitamins serve as catalysts and strengthen immune function.
In addition, vitamins, minerals and secondary plant compounds have an antioxidant effect. Together, they prevent free radicals from causing cellular damage.
Your body can also form antioxidants on its own. However, in order for them to provide cell protection, they require minerals such as zinc, manganese, iron, selenium and copper.
Foods that boost your immune system
To boost your immune system, you should always ensure that your diet meets your needs. As soon as the body’s defence weakens and an infection occurs, a vicious circle can be set in motion: a nutrient deficiency leads to infection. This, in turn, can lead to a further loss of nutrients via symptoms such as fever, loss of appetite or diarrhoea.
According to studies, the following nutrients have the greatest influence on the immune system:
- Vitamins A, C, D and E
- Zinc and selenium
- Omega-3 and omega-6 fatty acids
- Prebiotics and probiotics
Particularly in old age, it is absolutely crucial to maintain a diet that meets individual needs. With increasing age, the feeling of lack of appetite can increase, which can lead to malnutrition. Subsequently, a protein deficiency leads, for example, to a decrease in T cells.
What does vitamin A do for the body?
From birth, vitamin A influences the development of the immune system. If the body lacks vitamin A, the immune system suffers – scavenger cells and T killer cells lose their effectiveness. In addition, animal studies have shown that the protective function of the intestinal mucosa can decrease.
Did you know that the intestinal mucosa functions as a barrier for the immune system; it prevents harmful bacteria and viruses from entering the bloodstream.
Vitamin A, or its precursor beta-carotene, is found in offal, orange, yellow, and green fruits and vegetables.
Vitamin D and immune system health
For a long time, it was assumed that vitamin D only regulates bone formation. However, researchers have been able to show that vitamin D strengthens the activity of immune cells, especially macrophages. Current research results indicate that an adequate vitamin D supply reduces the risk of autoimmune diseases, such as type 1 diabetes.
To prevent vitamin D deficiency, spend at least 30 minutes outdoors on sunny days and take vitamin D supplements if levels are too low.[1, 5, 6]
Curious to find out more about the benefits of vitamin D? Visit our Health Portal article for more insights into vitamin D deficiency.
Boost your immune system with vitamin C and vitamin E
When it comes to immune system function, vitamin C and vitamin E are a good team. Vitamin E protects cell membranes from free radicals: cells remain stable and can perform their functions. After scavenging free radicals, vitamin E itself becomes a free radical and vitamin C comes into play. It converts the vitamin E radical back into an ordinary vitamin E molecule.
The body also needs vitamin C to make B and T cells. Vitamin C additionally helps immune cells find pathogens more quickly.
Vitamin E is found mainly in vegetable oils and nuts, while vitamin C is abundant in peppers, kiwi, berries and citrus fruits.[1, 7]
Zinc, selenium and iron
Minerals such as iron and zinc are involved in the formation of immune cells, and zinc and selenium have an additional antioxidant effect. Both a zinc deficiency and a selenium deficiency impair the functioning of macrophages and T cells. With iron deficiency, the thymus gland cannot provide sufficient immune cells.
Zinc and selenium are found in high amounts in whole grains and nuts. Iron is found in meat, nuts, whole grains, broccoli and kale.
You can test your mineral levels and ensure that they remain healthy with a mineral test.
Do I need prebiotics or probiotics?
A total of 70 per cent of the immune system is located in the intestine. The intestinal bacteria located there fight pathogens and prevent them from spreading around the body.
Infections, antibiotics, an unhealthy diet and chronic stress promote an imbalance in the intestinal flora. Harmful bacteria can thus gather in the intestine, pass through the intestinal mucosa more easily and enter the bloodstream.
To curb the effects of antibiotics, it is recommended that you take probiotics – dietary supplements containing intestinal bacteria to strengthen the intestinal flora. Fermented foods such as sauerkraut, kefir and kimchi, and cheeses such as mozzarella and cheddar contain probiotic bacteria.
Prebiotics support the growth of intestinal bacteria that fight pathogens and strengthen our intestinal lining. Prebiotics are found in whole grains, fruits and vegetables.
A healthy immune system with omega 3 and omega 6
The polyunsaturated fatty acids omega 3 and omega 6 regulate blood circulation, among other things: while omega 3 fatty acids promote blood circulation, omega 6 contributes to blood clotting. To maintain heart health, the optimal ratio of omega 6 to omega 3 in the body should be five to one. According to studies, higher levels of omega-6 fatty acids may not only increase the risk of heart disease, but also immune disorders.[8, 9]
To optimise your omega-3 levels, you can consume a tablespoon of cold-pressed virgin flax oil daily, a handful of nuts, and eat coldwater fish, such as mackerel or herring once a week. Omega-3 supplements based on fish oil or, as a vegan option, algae oil are also an option.
Please note: Only take supplements if you have a confirmed deficiency. Make sure you eat a balanced and varied diet to absorb all the important nutrients.
Gain a wealth of knowledge on omega-3 and omega-6 fatty acids by reading our Health Portal article!
Obesity and immune system health
Obesity is accompanied by a number of inflammatory processes: the fat cells secrete adipokines, proteins that promote inflammation. They interfere with the signal transmission of the white blood cells and the immune system – inflammations are therefore not detected in time. In addition to excess weight, large amounts of food that exceed actual requirements can also promote inflammation.[11,12]
How nutrition can boost your immune system
You are greatly supporting your immune system if you consume sufficient amounts of vitamins, minerals and omega-3 fatty acids. A balanced diet with plenty of fruits and vegetables, nuts and fish will have you covered when it comes to most nutrients. You can check your levels with nutrient deficiency tests. Regarding probiotics and prebiotics, you can strengthen your intestinal flora and thus additionally boost your immune system in your intestine.
Stress and immune system health
Stress is felt in situations that emotionally overwhelm you – the body releases stress hormones, such as cortisol, in response to such situations.
How does stress affect the immune system?
Chronic stress and thus elevated cortisol levels prevent immune cells from fighting pathogens in a timely and effective manner. Furthermore, chronic stress impairs the formation of lymphocytes and humoral immune response – the body produces fewer antibodies to fight pathogens.[10,13]
Well-being and the immune system
Making your everyday life less stressful not only brightens your mood, but it also strengthens your immune response: the body produces more and more active T cells. Natural killer cells also work more effectively. Well-being is also thought to lower the risk of autoimmune diseases and the incidence of free radicals.
To make everyday life less stressful, implement these changes in your life:
- Get sufficient and restful sleep to reduce your stress levels.
- Do exercise to counteract stress – especially if it’s a sport you love.
- Drink black tea; this is said to counteract the release of stress hormones.
- Consume enough omega-3 fatty acids, B vitamins and antioxidants via your diet.
- Daily relaxation techniques such as meditation, yoga or qigong have been shown to lower your cortisol levels.
Being with your loved ones stimulates the production of the cuddle hormone oxytocin. This hormone reduces stress levels and even strengthens the immune system.
Sleep and the immune system
A sleepless night not only makes you feel tired in the morning or shiver throughout the day, it can also make you feel ill. It furthermore increases the risk of you getting sick more often. This is because the body needs sufficient sleep for optimal immune function. Following the start of the Covid-19 pandemic, the number of people experiencing sleeping disorders reportedly increased sharply to 25 per cent among the British population, with women especially experiencing a pronounced decline in their sleep quality.
How does sleep affect the immune system?
During sleep, the formation of defence cells, such as T cells and natural killer cells takes place. During this time, the lymphocytes are particularly active. Their task is to recognise potential threats in good time, while recovery and repair processes take place.
If you don’t receive sufficient sleep, fewer immune cells are also produced. The body then releases more inflammatory substances and stress hormones, which reduce immune activity.[17, 18]
Did you know that stress hormones affect glue proteins? These proteins help T cells to dock onto pathogens. During restful sleep, hardly any stress hormones are released. That is why it helps glue proteins and thus also T cells to work unhindered.
With the right sleeping routine, you can drastically boost your immune system:
- Always try to go to bed and get up at the same time.
- Your bedroom should have a temperature of around 18 degrees Celsius.
- Don’t watch TV or look at your smartphone two hours before bedtime.
- Have your last meal of the day four hours and your last coffee six hours before bedtime.
- The sleep hormone melatonin plays an essential role in you falling asleep and staying asleep. If there are disturbances in your melatonin balance, melatonin supplements can help.
Is sport good for immune system health?
Sports boost your immune system: when you exercise regularly, your blood flow improves. The better the blood can flow, the faster immune cells can detect pathogens and fight them.
Researchers observed that physical activity can increase the activity of natural killer cells and granulocytes. In addition, exercise is thought to curb the weakening of the immune system, which happens when you get older. Try to schedule five 30-minute exercise sessions a week. But don’t overdo it – overly intense workouts may weaken your immune system.
If you consume carbohydrates after your exercise session, the risk of inflammation may be reduced.[20, 21]
While free radicals are formed after exercise, they are not formed to a degree that harms the immune system. 
Ways to boost your immune system
Immune boosters are foods or dietary supplements that are designed to boost your immune system. The market for these immune boosters are booming: in 2018, nearly 225 million dietary supplements were sold in Germany, primarily vitamin C preparations.
Often, such supplements are marketed as magic bullets in fighting against infections. However, studies show that most of them do not necessarily work: taking either zinc or vitamin C supplements, for example, does not prevent a cold – they may only shorten the duration of the illness.
Dietary supplements should mainly be taken when there is a confirmed deficiency or when certain nutrients cannot be absorbed from the diet due to illness, allergies or intolerances. [23, 24]
Preparations with isolated nutrients do not always show the same effect as food. The effect of nutrients is usually strengthened by the presence of other nutrients in the particular food or meal.
Nevertheless, there are home remedies or foods that, according to studies, can strengthen the immune system. So far, success has mainly been observed in animal studies.
Foods that boost your immune system
Ginseng, ginger and garlic promote a healthy immune system. They strengthen the activity of immune cells such as natural killer cells, macrophages and granulocytes.[25, 26]
Spicy foods such as chilli or peppers contain the secondary plant compound capsaicin – this supports the elimination of defective or harmful cells and pathogens.
Curcumin from turmeric can increase the production of B cells, T cells and natural killer cells. The phytochemical may also increase the response rate of the immune system.
The amino acid theanine from green or black tea and the medicinal plant echinacea was found to improve immune function in rats.[29, 30]
Do smoking and alcohol weaken your immune system?
Sometimes it is said, albeit jokingly, that alcohol and cigarettes could perhaps also kill viruses and bacteria with their toxins. Unfortunately, this is not true.
Alcohol and the immune system
Studies suggest that alcohol abuse even inhibits certain immune cells, weakening the immune system and increasing the risk of infection.
If you spend the evening heavily intoxicated in a busy bar or pub, your body is less able to fight off the pathogens that are spread around.
In one study, it was proven that 20 minutes after the test subjects drank a large amount of vodka, inflammation levels and defence processes in the body briefly increased. After two hours, however, the immune system was depleted, and the number of defence cells such as monocytes (phagocytes) and natural killer cells decreased. According to the researchers, therefore, even a single drink increases the risk of becoming ill.
However, individual studies suggest that limited alcohol consumption may actually make the immune system stronger in the long run. However, these results are controversial among researchers – and other recent studies suggest that even smaller amounts of alcohol are generally unhealthy and could increase the risk of cancer and other illnesses.
How does smoking affect the immune system?
Smoking first of all has an effect on the outermost protective walls of the immune system: the mucous membranes of the respiratory tract and the cilia of the lungs. This makes it easier for pathogens to penetrate our airways and can thus increase the risk of pneumonia, among other things.
Defence cells also appear to suffer from nicotine intake. It has been shown that smokers, on average, suffer more frequently from infections such as colds.
You can not only boost your immune system in the long term, but also ensure that you come into contact with fewer pathogens in everyday life. The measures to do this may seem small and insignificant at first, yet you have an enormous influence on the body’s defence.
How do I fight off illness?
Good hand hygiene is a must. Wash your hands regularly if you have come into contact with possible sources of pathogens – whether in the bathroom, kitchen or public toilets.
When you sneeze or cough, cover your mouth with your elbow to avoid infecting others.
Open sores should be washed out immediately with lukewarm water and covered with a bandage or plaster.
Condoms can protect against sexually transmitted infectious diseases, such as HIV, syphilis and gonorrhoea.
To remove as many pathogens as possible from food, wash food thoroughly first. Raw animal products must be well heated and cut on a separate cutting board. If you are going abroad, it is advisable to find out in advance whether the drinking water is contaminated with bacteria.
Tip: Before travelling, always find out how high the risk of infectious diseases is in the respective country, so that you can take appropriate precautions.
Vaccinations are used to protect against certain diseases. Small amounts of a certain pathogen are injected, after which your body can form antibodies in advance. If an infection with this pathogen should occur, your body can counter the infection with the appropriate antibodies. You can get vaccinated against the following diseases and pathogens:
- Tetanus, diphtheria
- Whooping cough, influenza (flu)
- Hepatitis B
- Shingles, pneumococcus, rotavirus, meningococcus, HPV
- Measles, mumps, rubella, chickenpox, polio
Testing your immune system
With an immune system test, you can take a blood sample within the comfort of your own home for doctors to analyse in a specialised laboratory. Doctors check the presence of lymphocytes in your blood – an indication of how strong or weak your immune system is at the time the test was taken.
Following the laboratory analysis, you will receive a detailed and personal results report telling you about the lymphocyte count in your blood and how you will be able to boost your immune system to an optimal level to fight off future infection.
Boost your immune system – at a glance
How can I strengthen my immune system?
To ensure that your immune system protects you from infections in the long term, you should make sure you eat a balanced diet that meets your needs, so that you take in enough nutrients to boost your immune system. These include vitamins A, C, D and E, zinc, selenium and iron. Furthermore, you should make sure you regularly get a restful sleep, sufficient exercise and maintain low stress levels in everyday life. Vaccinations and optimal personal hygiene also prevent the risk of infections.
Which are the best foods for immune system health?
Foods that are said to strengthen the immune system include ginger, garlic and medicinal plants such as ginseng or echinacea. Spicy foods containing the active ingredient capsaicin are also said to be immune boosters. Theanine from green and black tea and curcumin from turmeric are said to have similar positive effects on your immune system.
How do I protect myself from pathogens?
When viruses or other pathogens are going around, you can take small steps to help prevent you and others from catching them. Wash your hands thoroughly, sneeze into your elbow and not your hand, and always wash fresh food. During flu season, the flu vaccination can also be protective.
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