We are exposed to countless pathogens like viruses, bacteria, and fungi every day. To combat them, our body has a natural secret weapon: the immune system. The immune system is a complex, biological defense system and as individual as we are. But what exactly does the immune system do, and what measures can we take to support it as best as possible? In this article, you will learn everything about the body's immune defense and what tips you can apply to get through late winter fit and strong.
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What's behind our immune system
A statistic from the Consumer Insights Global Survey, conducted in Germany in 2023, shows that approximately 48% of respondents experienced cold symptoms in the last 12 months. These include coughs, sore throats, or a runny nose. 1
It is therefore not uncommon for our body's protective barrier not always to be able to withstand all pathogens and harmful environmental influences. Nevertheless, the immune system is an ingenious, naturally given construct that works around the clock to protect our body from harmful invaders.
The immune system is individually configured, as it depends on several factors such as genetics, environmental influences, lifestyle, microbiome composition and diversity, as well as age and immunity due to previous illnesses or vaccinations. Our immune system is vital for us. Without this natural protective mechanism of our body, even harmless germs would be enough to put us in a life-threatening situation. Even protection against simple injuries or dangerous cancer cells would be impaired.
However, the functioning of our immune system does not always proceed in the same way. Have you ever wondered why we usually get sick in winter? Researchers from Great Britain investigated this and found that the immune system in the European winter shows an increased number of genes that are pro-inflammatory. Biomarkers were identified that represent a risk for cardiovascular, autoimmune, and psychiatric diseases, which are particularly common in winter. Furthermore, some genes are more active in winter and others more in summer. This shows that our immune system varies depending on the season. 2
Dr. Chris Wallace, who conducted this study with Prof. John A. Todd, said: "Our study suggests that human immune systems show different seasonal variations in regions with less distinct seasons than in regions with greater differences between winter and summer." Prof. John A. Todd added: "Given that our immune systems put us at higher risk of inflammation-related diseases in the colder, darker months, and given that we already understand the benefits of vitamin D, it makes sense that people crave some 'winter sun' to boost their health and well-being." 3
In addition, stress, medication courses such as taking antibiotics, lack of sleep, insufficient exercise, poor nutrition, harmful environmental influences such as air pollution and chemicals, and alcohol consumption can significantly weaken our natural immune system.
Our immune system: briefly explained
One thing is clear: we can be proud of our functioning immune system. The complexity and ingenuity behind it are fascinating. Equally exciting is the fact that our immune system consists of an innate (non-adaptive) and an acquired (adaptive) immunity. These two forms of immunity complement each other and fulfill different tasks.
Innate Immunity
As soon as germs enter the body, the innate immune system reacts directly to them. It acts very quickly and can detect and destroy pathogens in a very short time. However, innate immunity is only partially able to completely stop the spread of pathogens. At this point, acquired immunity takes over.
Acquired Immunity
Acquired immunity has the ability to specifically target pathogens. This takes a little more time, which is why acquired immunity reacts a little later but is effectively tailored to the specific invaders. Acquired immunity can "remember" attackers through memory cells and react more quickly and specifically to a new infection. This is why we usually only get some diseases like chickenpox or mumps once in our lives. Vaccinations also work on this principle: they were developed to specifically activate the acquired immune system and ensure long-term immunity against certain pathogens.
Weakened Immune System: Symptoms
A weakened immune system does not necessarily manifest through frequent colds or infections, although these symptoms are definitely associated with a weakened immune system. The following symptoms can also be an indication that the immune system is impaired:
- Long duration of illness
- Chronic fatigue
- Lack of energy and exhaustion+
- Allergies
- Intolerances
- Skin rashes and inflammation
- Pain
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Poor wound healing
How to effectively boost your immune system
Especially in winter and late winter, colds often circulate, putting our immune system on high alert. Cold temperatures and heated rooms provide the perfect dry environment for pathogens to multiply. Dry mucous membranes are one reason why the body cannot effectively fight pathogens. Furthermore, factors such as lack of exercise and little time spent outdoors can lead to significant restrictions of the immune defense. Nevertheless, we have compiled valuable recommendations for you on how you can support your immune system to better protect yourself from colds and the like. Here are our tips:
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Sufficient Sleep
Sleep is necessary for the regeneration of our body and our cells. Scientists from the University of Tübingen and the University of Lübeck found in a study that the function of T-cells - the white blood cells that fight pathogens - was impaired after only three hours without sleep. 4
This study shows that sleep plays a central role in maintaining our immune system. However, sleep duration and sleep quality must also be considered. Researchers at Duke University found that women suffer significantly more from the mental and physical effects of sleep deprivation compared to men. 5 If you want to learn more about sleep and how to improve your sleep, we recommend our article More restful sleep with 5-HTP.
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Forest Bathing
Forest bathing refers to a short and relaxing stay in the forest. A walk in the forest has a very special ability: improving your immune system. This was shown by a series of Japanese studies that investigated the effects of forest bathing on the immune function of men and women. The subjects underwent a 3-day/2-night trip to forest areas. Blood and urine samples were regularly taken. It was found that the number of natural killer cells was higher on the days of forest bathing than on the control days. 6 Furthermore, a forest walk optimally helps to lower cortisol levels.
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Sunlight
The human body depends on sunlight, because sun means vitality. With the help of sunlight, our body can produce vitamin D. Vitamin D is a vitamin that is very important for a healthy immune system. Unfortunately, we in Germany, among others, increasingly struggle with vitamin D deficiency. Vitamin D supports the function of immune cells so that they can more effectively combat pathogens. In addition, the body releases serotonin through sunlight, a neurotransmitter known to lift mood.
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Drink plenty of fluids
You should always ensure that your body is adequately hydrated. This not only helps to flush out toxins that burden your immune system but also to keep your mucous membranes moist. Heating air quickly dries out our mucous membranes, which can create an optimal environment for pathogens. Generally, 1.5-2 liters are recommended daily, as a large part is also consumed through food.
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Healthy Diet
A wealth of existing data shows that certain vitamins, including vitamins B6, B12, A, C, D, E, and folic acid, as well as trace elements such as iron, zinc, selenium, magnesium, and copper, and the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid, are indispensable for a healthy immune system. 7
You can find these nutrients in the following foods:
Vitamin B6: fish, avocado, chicken, lentils, bananas
Vitamin B12: meat, eggs, dairy products
Vitamin A: carrots, pumpkin, sweet potatoes
Vitamin C: citrus fruits, berries, broccoli, tomatoes
Vitamin D: eggs, dairy products, meat
Vitamin E: olive oil, avocado, hazelnuts, sunflower seeds
Folic acid: kiwi, oranges, spinach, lentils Iron: red meat, dates, spinach, lentils
Zinc: spinach, oats, quinoa, lentils, chickpeas
Selenium: nuts, seeds, beef, lamb, pork, tuna Magnesium: spinach, lentils, bananas, fish
Copper: dark chocolate, cocoa powder, lentils, oats, beef liver Omega-3 fatty acids: flax seeds, chia seeds, walnuts
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Antioxidant Foods
There are numerous foods that have an antioxidant effect. They help protect the body from inflammation and damage caused by free radicals. Honey, onions, garlic, turmeric, and ginger are particularly antioxidant. These are often also referred to as natural antibiotics.
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Limiting consumption of alcohol, cigarettes, sugar, and processed foods
It's no secret that alcohol, cigarettes, sugar, and processed foods are bad for us in excess. All these substances are associated with weakening the immune system, causing inflammation, and in the worst case, even cancer. To avoid this, we recommend a balanced and varied diet with unprocessed foods.
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Spicy Foods
Some spicy foods - including chili - contain the chemical compound capsaicin. Capsaicin is said to have antibacterial and antiviral properties. This, in turn, can help counteract pathogens and protect the immune system.
Another positive side effect is that spicy foods stimulate saliva production, which allows the mucous membranes to moisten. In addition, spicy foods like chili or ginger stimulate digestion. Proper digestion and a healthy gut flora are important for an intact immune system, as a large part of the immune cells are located in the gut.
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Hygiene (especially hand hygiene)
We are not even aware of how many germs we come into contact with daily, just through our hands. Be it doorknobs, shaking hands, handles or buttons in public transport, and much more. All these are germs that could pose a potential danger to us. Therefore, it is important to wash hands regularly and thoroughly (approx. 20 seconds with water and sufficient soap) and to disinfect them if necessary. This can significantly reduce the risk of infection.
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Stress Management
Stress is a known trigger for psychological and physical suffering. Over time, however, stress has become an everyday problem, and more and more people feel permanently stressed. Stress can increase cortisol levels, which in turn impairs the normal function of the immune defense. There are numerous ways you can effectively counteract stress in everyday life. Good options include yoga, meditation, or progressive muscle relaxation. In our article Natural stress management for men and women: tips for relaxed holidays, we list helpful tips that show you how to relax in everyday life.
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Regular Sauna Visits
Regular sauna visits are considered health-promoting, as they are associated with strengthening the immune defense. Intense sweating promotes the excretion of harmful toxins from the body. Furthermore, saunas promote circulation and blood flow, which strengthens the cardiovascular system. Another advantage of saunas is that the mucous membranes and respiratory tracts are moistened. This can help to loosen stubborn mucus. Metabolism is also stimulated by the heat. Sauna visits also enable true moments of relaxation and help to lower cortisol levels. However, caution is advised for high blood pressure or heart problems - in these circumstances, saunas are strongly discouraged!
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Ice Bathing
Ice bathing promotes blood circulation because the alternation between cold and warmth causes blood vessels to constrict and then expand again. This process is enormously beneficial for the cardiovascular system and can help support the immune system. Additionally, anti-inflammatory processes are stimulated, and stress is reduced. However, caution is also advised for ice bathing if you have pre-existing conditions. It is best to consult a doctor beforehand.
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Alternating Showers
Exposure to cold can stimulate the immune system, as here too, the interaction of cold and warmth promotes blood circulation. This supplies the organs with more oxygen and nutrients. Alternating showers release happiness hormones that make you feel awake and refreshed after showering.
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Shock Ventilation
Shock ventilation is particularly important in winter, as dry indoor rooms urgently need to be humidified. It is sufficient to ventilate for approx. 5-10 minutes. With daily shock ventilation, you will notice that your mucous membranes are no longer quite so dry.
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Supplements that Boost the Immune System Multivitamin supplements are particularly popular because they combine several nutrients in one capsule. This simplifies the daily intake of important minerals and vitamins. This is especially important for those who have a hectic and rather stressful everyday life. Multivitamin supplements therefore offer the perfect opportunity to actively support the immune system in addition to a balanced and healthy diet.
Our All-Day-Multi supports you and your immune system with the following vitamins and minerals: Vitamins A, C, D, all 8 B vitamins, iron, copper, manganese, magnesium, selenium, and zinc. Especially vitamins A, C, D, B, and the minerals zinc and selenium contribute to the normal function of the immune system.
B vitamins, iron, and magnesium are important components for regulating the nervous system. The All-Day-Multi contains all 20 important nutrients you need in your daily life to effectively cope with it and additionally support your immune system.Advertisement
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Zinc Bisglycinate
Zinc is available in several forms on the market. However, zinc bisglycinate is a specific chemical compound that has particularly high bioavailability and can be better absorbed and utilized by the body. This form of zinc is considered particularly well tolerated. Zinc is an essential mineral that contributes to the normal function of the immune system, the maintenance of normal skin, the support of a normal metabolism, and normal cognitive function. For these reasons, you should consider taking zinc bisglycinate if you have a weakened immune system.
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Prebiotics and Probiotics
The gut is the most important organ when it comes to an intact immune system. It is known that 70-80% of immune cells are located in the gut, making it the center of immune defense. With the help of prebiotics and probiotics, you can support your gut flora and promote the balance of good bacteria. This is not only good for your immune system but also for your overall well-being.
There are numerous foods that have prebiotic and probiotic effects. Prebiotic foods include onions, garlic, oats, and bananas, while kefir, yogurt, sauerkraut, kimchi, and fermented products are among the probiotic foods.
You can learn more about the gut, our digestion, and the microbiome in this blog post our microbiome: how to support your digestion.
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Detox Cleanses
Detox cleanses are designed to help the body cleanse itself of toxins. These cleanses can be carried out in various ways, depending on what one likes or prefers. There are specific juice cleanses, diets, and fasting methods that can be used to stimulate digestion and promote detoxification. Especially therapeutic fasting and intermittent fasting are popular fasting methods that are practiced by many and seen as a trend.
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Infusion and Nutrient Therapy
This type of treatment is primarily suitable for people who suffer from a severe and acute nutrient deficiency due to health restrictions. Vitamin and mineral infusions go directly into the bloodstream and can therefore be effectively absorbed by the body. It offers a good option if you suffer from a specific vitamin or mineral deficiency that needs to be supplied quickly and in high amounts.
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Strengthening Mental Health
Strong and stable mental health is extremely important. Not only for our psyche but also for the immune system. Our brain and our gut can communicate with each other via the so-called gut-brain axis. If your gut is not well, the gut signals this to the brain. Since the majority of our immune defense is in the gut, mental well-being has a very great influence on our immune system.
Thus, chronic stress, inner restlessness, or depression can progressively weaken the immune system. Therefore, it is important to maintain and constantly care for mental health through stress management, regular breaks, good sleep hygiene, and a healthy diet.
Conclusion
Our immune system is what keeps us alive and protects our body from numerous pathogens every second. The immune system is thus active around the clock and even when we sleep. It is therefore possible that infections occasionally occur in our body that cannot be directly fought off. To avoid this, it is important to give our body and immune system the necessary attention and to support them through a balanced and nutrient-rich diet, sufficient exercise, good hygiene, and strengthening mental health.
Sources:
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Statista. (2025). Survey on health complaints in Germany. Statista. https://de.statista.com/statistik/daten/studie/671474/umfrage/umfrage-zu-gesundheitlichen-beschwerden-in-deutschland/
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Dopico, X., Evangelou, M., Ferreira, R. et al. Widespread seasonal gene expression reveals annual differences in human immunity and physiology. Nat Commun 6, 7000 (2015). https://doi.org/10.1038/ncomms8000
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University of Cambridge. (2024, January 7). Seasonal immunity: Activity of thousands of genes differs from winter to summer. University of Cambridge. https://www.cam.ac.uk/research/news/seasonal-immunity-activity-of-thousands-of-genes-differs-from-winter-to-summer
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University of Tübingen. (2019). How sleep strengthens the immune system. University of Tübingen. https://www.medizin.uni-tuebingen.de/de/das-klinikum/pressemeldungen/meldung/153
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Medical Daily. (2025, January 8). Why women need more sleep than men: Research shows stronger mental, physical response to inadequate rest. Medical Daily. https://www.medicaldaily.com/why-women-need-more-sleep-men-research-shows-stronger-mental-physical-response-inadequate-rest
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Li Q. Effect of forest bathing trips on human immune function. Environ Health Prev Med. 2010 Jan;15(1):9-17. doi: 10.1007/s12199-008-0068-3. PMID: 19568839; PMCID: PMC2793341.
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Calder, P. C., Carr, A. C., Gombart, A. F., & Eggersdorfer, M. (2020). Optimal Nutritional Status for a Well-Functioning Immune System Is an Important Factor to Protect against Viral Infections. Nutrients, 12(4), 1181. https://doi.org/10.3390/nu12041181
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