Winter brings not only cold and shorter days, but also a higher risk of respiratory illnesses—from the common cold to influenza or airway inflammation.
Weakened immunity, less time outdoors in fresh air, overheated indoor spaces, and a lack of sunlight create ideal conditions for these illnesses.
A holistic approach to health includes not only prevention through nutrition and supplements, but also caring for the microbiome, mental well-being, quality sleep, and intentional rest—key factors that help the body handle infections naturally.
What will you learn in this article?
- Why the respiratory tract is more vulnerable in winter
- Prevention: How to strengthen the immune system naturally
- How to strengthen mucosal immunity
- Key nutrients and supplements for strong immunity
- Caring for the respiratory tract
- What to do when you get sick
- Key takeaways
Why the respiratory tract is more vulnerable in winter
Cold winter air places a significant strain on the respiratory system. Low temperatures cause the airways to constrict and increase mucus production, which worsens airflow and makes it easier for infectious particles to settle.
The combination of spending time indoors, dry air from heating, and a lack of sunlight weakens the natural protective mechanisms of the mucous membranes. Add to that lower levels of vitamin D and more frequent stress, and together they create an ideal environment for viruses and bacteria.
Prevention: How to strengthen the immune system naturally
A healthy, balanced, nutrient-dense diet is the foundation of prevention—not only for respiratory illnesses. Our immunity is closely linked to the state of the gut microbiome and an adequate intake of key nutrients.
What to prioritize in your diet:
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Anti-inflammatory foods – leafy greens, garlic, onions, ginger, berries, nuts, and fish rich in omega-3 fatty acids.
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Fermented foods – kefir, sauerkraut, kimchi, or yogurts with probiotic cultures that support a healthy microbiome.
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Warm, nourishing meals – soups, broths, and stewed vegetables help maintain internal warmth and support proper immune function.
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Enough fluids – herbal teas (elderflower, linden blossom, mallow, thyme, or ginger) help moisturize the airways and support hydration.
On the other hand, excessive intake of sugar, alcohol, coffee, and ultra-processed foods can weaken immunity, promote inflammation, and disrupt gut balance.
How to strengthen mucosal immunity
Mucosal immunity (so-called mucosal immune system) is the first and one of the most important defensive lines of our body. It protects us exactly where we are most exposed to contact with the outside environment—on the mucous membranes of the respiratory tract, digestive tract, and the urinary and reproductive systems. This is where viruses, bacteria, fungi, or toxins most often enter the body.
Unlike immune reactions that take place inside the body (for example via white blood cells and antibodies in the blood), mucosal immunity acts on the surface of mucous membranes. The basic protection here is immunoglobulin A (IgA)—an antibody that forms a protective film and prevents pathogens from attaching to the mucosa and penetrating tissues.
The mucosa is also densely populated by the microbiome—billions of friendly bacteria that, together with mucosal immunity, form a defensive barrier. These bacteria compete with pathogens for space and nutrients, and also send signals that “teach” immune cells how to respond properly. When the microbiome is in balance, immunity works optimally. Conversely, when it is disrupted (e.g., after antibiotics, due to stress, poor nutrition, or lack of sleep), immune defenses weaken significantly.
Mucosal immunity is closely connected to the overall immune system. Up to 70% of immune cells are located in the gut, which explains why a healthy gut microbiome is so essential for defense not only of the digestive system but also the respiratory or urinary system. If the intestinal mucosa is out of balance, the risk of recurrent infections, food intolerances, or allergies increases.
For optimal mucosal immune function, adequate nutrition, hydration, a healthy microbiome, and recovery are necessary. Key roles are played by vitamins A, D, C, zinc, selenium, and omega-3 fatty acids, which support mucosal renewal and a proper immune response. Foods naturally containing probiotics and prebiotics are also important, as they synergistically help maintain microbial balance.
Key nutrients and supplements for strong immunity
In winter, it can be harder to cover all of the body’s needs through diet alone. That’s why it can make sense to support the body with supplements that strengthen the immune and respiratory systems. If an illness develops, you can include higher doses of these supplements for a limited time to speed up recovery:
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Vitamin D3 (supplement together with vitamin K2)
Vitamin D plays a far more significant role in the immune system than most people realize—it regulates immune responses and helps the body respond to infections, thereby reducing the risk of infections and autoimmune diseases. Its optimal level should be between 100–150 nmol/L. To find out your vitamin D level, we recommend lab testing or trying our at-home dried blood spot self-test – Vitamin D Level.
During the winter months, vitamin D levels naturally drop due to less sunlight and a lower sun angle. This weakens the body’s first line of defense— upper respiratory tract infections then become more frequent and can have a longer course.
A number of studies (e.g., Martineau et al., BMJ 2017) confirm that vitamin D supplementation reduces the risk of acute respiratory infections by 30–50%, especially in people with low baseline levels.
Recommended daily dose: 1,000–2,000 IU for prevention (depending on individual needs, higher doses can also be supplemented short-term)
In relation to the immune system, it supports healthy function and helps reduce fatigue and exhaustion.
Recommended daily dose: Regular supplementation with lower doses of vitamin C (75 mg up to 3× daily) from a natural source such as Acerola. When needs are higher (a cold), vitamin C doses can be increased severalfold short-term (total 1–2 g in liposomal form in divided doses of 250–500 mg throughout the day).
Supports the immune system and reduces the risk of infections, which is why demand for it increases during illness.
Recommended daily dose: 7–15 mg (ideally as zinc bisglycinate; during illness it may be appropriate to supplement higher doses short-term on an individual basis—30–45 mg—which can reduce the duration of a cold)
They reduce inflammatory processes in the body and support the immune system.
Recommended daily dose: 1,500–3,000 mg omega-3
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B-complex
Contributes to healthy mucous membranes and therefore to their proper function.
Recommended daily dose: Usually individual, taking into account diet and other demands of the body.
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Herbs
Echinacea, elderberry, mallow, thyme, or ginger increase the body’s resilience and may shorten the duration of illness.
If symptoms worsen, you develop a fever, or you feel chest pain, we recommend visiting your doctor.
Caring for the respiratory tract
Preventing respiratory illnesses is not only about nutrition, but also about practical protection of the airways. The immune system works best when the body has enough strength and time to recover.
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Breathe through your nose, not your mouth – the nasal cavity naturally warms, humidifies, and filters the air.
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When outdoors, protect your mouth and nose with a scarf, so overly cold air doesn’t reach your lungs.
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Keep your home temperature around 18–21 °C (especially in the room where you sleep) and maintain adequate humidity, ideally 40–60%. Avoid overheating rooms.
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Avoid mold and smoke, which can irritate the airways.
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Inhalation or steam bath with essential oils (e.g., eucalyptus, mint) moisturizes the mucosa and helps open the airways.
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Sleep is key – aim for 7 to 9 hours of sleep regularly, which will help keep your immune system stronger.
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Regular movement – even a light walk or breathing exercises that support lung capacity.
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Stress management – meditation, breathing techniques, or relaxation help lower cortisol levels, which can weaken immunity.
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Sauna or alternating hot and cold water supports overall immune resilience.
What to do when you get sick
If you do get sick, give yourself peace and rest, plenty of fluids, and easy-to-digest nourishment. The body needs energy for recovery, not for digesting heavy meals. Broths, high-quality protein, and stewed vegetables are good choices. Avoid smoking and alcohol, which put extra strain on the respiratory tract.
People with chronic lung disease should always consult a doctor in winter if their condition worsens.
Key takeaways
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Winter significantly increases the risk of respiratory infections because cold air weakens the mucous membranes, indoor air tends to be dry, and vitamin D levels drop.
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The foundation of prevention is strengthening immunity — a quality diet, enough sleep, hydration, movement, and support for the gut microbiome.
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Mucosal immunity is the first line of defense and depends on healthy mucous membranes, adequate nutrients, and a balanced microbiome.
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Key micronutrients for winter immunity: vitamin D, C, zinc, selenium, omega-3, and a B-complex; they can significantly reduce the risk of respiratory illness.
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Herbs such as echinacea, elderberry, thyme, or ginger support immune defenses and may shorten the duration of illness.
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Practical respiratory care (breathing through the nose, humidifying the air, inhalation, protection from cold) significantly reduces the risk of infection.
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Recovery is essential — quality sleep, stress hygiene, and rest strengthen immune responses.
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When sick, the most important things are rest, fluids, and light meals; always consult a doctor if your condition worsens.
Sources:
https://www.who.int/tools/elena/commentary/vitamind-pneumonia-children
https://pmc.ncbi.nlm.nih.gov/articles/PMC11193220/
