The autumn and winter period is a big challenge for our body. Temperature fluctuations, wind and rain make us sick much more often at this time. Building a natural defence is a long-term process and involves many factors. It is worth knowing how to gradually improve your condition and not get infected. What should be especially taken care of during this demanding time? How do we strengthen the body in natural ways?

How does the immune system work?

The immune system is designed to protect the body against pathogenic microorganisms, which it first detects and then eliminates. Firstly, we have an innate immune response, which we have from the beginning of life and it is the first line of defence - and acquired (specific) - which must be created by prior contact with the antigen (after getting sick or after being vaccinated). The organs of the immune system are located throughout the body. The central ones include the bone marrow and the thymus. In turn, the peripheral - spleen, lymph nodes, tonsils and lymphatic tissue of the mucous membranes of the digestive tract and exocrine glands, respiratory tract and skin [1].

It is important to know that the functioning of the immune system can be improved by taking a few simple steps.

How to strengthen your immunity? First - healthy habits

Although medicine offers many effective solutions that are aimed at strengthening the body, it is important not to forget about the foundations of staying healthy. More and more attention is paid to the fact that the basis of self-care should be specific daily habits. Having a healthy lifestyle is primarily the right amount of good quality sleep, regular physical activity and avoiding stress. Although it sounds trivial, it should be noted that there are factors that greatly affect the condition of the immune system.

A regenerated body supports the fight against infections

One of the factors affecting immunity is sleep, which plays a fundamental role in human health and well-being. Scientists confirm the impact of sleep and its lack on the functioning of the immune system and the risk of diseases related to the immune system. Inadequate regeneration can contribute to an increase in inflammatory markers. Most studies of immune function have shown that sleep enhances the immune response [2].

Physical activity and its impact on the efficient functioning of the immune system

It turns out that physical activity greatly supports the body's immunity. Regular physical training has a general anti-inflammatory effect on the body, and also improves immune regulation and delays the ageing process of immune system cells (immunosenescence) [3]. Positive immune changes occur during each episode of moderate physical activity, which over time translates into a shorter duration of colds and other respiratory infections. Already 30 minutes of almost daily physical activity has a positive effect on the functioning of the immune system [4]. Interestingly, intensive and long-term physical exercise - mainly in professional athletes - can cause temporary immunological disorders and increase the risk of infection [3,4]. So it is important to exercise in moderation..

Stress is the enemy of the immune system

Chronic stress increases inflammation in the body, which can have unpleasant consequences for health. There is a well-known link between stress and susceptibility to infection. Stress affects the cellular and humoral immune responses to pathogens and thus increases the risk of infectious diseases, including colds and flu [5].

Or maybe supplements for immunity? What to choose?

While getting enough sleep, avoiding stress, and exercising regularly may seem like a matter of course, in today's world, it's getting harder and harder to do so. No wonder that a large group of people are looking for additional support for their immune system. At the beginning, it is worth looking at your meals - they should provide optimal amounts of nutrients, including vitamins and minerals. Supplements that can be a good complement to the daily diet can also be helpful. For the proper functioning of the immune system, it is important to provide the body with adequate amounts of vitamin D and C, zinc and omega-3 fatty acids.

What to take to support immunity? Role of vitamin D in the functioning of the immune system

Vitamin D affects the immune response. Its low serum level is associated with a higher incidence of respiratory infections and exacerbation of the disease [6]. Studies on vitamin D supplementation in the prevention of acute respiratory infections indicate its protective effect [7].

Vitamin C, the most popular supplement for immunity

Vitamin C is essential for the proper functioning of the immune system. It stimulates the activity, multiplication and maturation of lymphocytes - cells of the immune system. Supplementation can prevent respiratory and systemic infections. Taking ascorbic acid is beneficial for the healing process - it is assumed that it alleviates the course and reduces the duration of the common cold. On the other hand, vitamin C deficiency may weaken immunity and increase susceptibility to disease [8].

Mineral component important for the body's immunity - properties zinc

Zinc is an important mineral whose adequate supply has a positive effect on the immune system, helps in wound healing and supports proper growth. It is involved in the regulation of the innate and acquired immune response. It is especially important for the proper functioning of the cells of the immune system. Additionally, zinc deficiency contributes to increased inflammation [9]. According to research, supplementation of this microelement may protect against upper respiratory tract infections and shorten the duration of cold symptoms [10,11].

Omega-3 acids protect immunity

Omega-3 fatty acids are polyunsaturated fatty acids, among which eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) stand out, which are known to have a beneficial effect on immunity and inflammation of the body - they have anti-inflammatory and antioxidant properties, increase the production and activity of cells of the immune system [12]. They also have antiviral properties by inhibiting the multiplication of the influenza virus [13]. Omega-3 acids are known for their immunomodulating effect, i.e. stimulating the immune system, therefore their supplementation can bring a number of benefits in maintaining homeostasis of the body [12,13].

Although we usually remember about strengthening the body in the autumn and winter season, it is worth remembering that building immunity is a process that takes time. Taking care of your health throughout the year means that we not only prevent diseases, but also better cope with the fight against infections. Getting enough sleep, avoiding permanent stress, practicing physical activity and providing the body with the necessary nutrients allows you to effectively improve the functioning of the immune system day after day.

[1] Marcinkiewicz J., Siedlar M. Fizjologia i podstawy organizacji układu immunologicznego. Medycyna Praktyczna. Pobrano 14.11.2022 z https://www.mp.pl/podrecznik/pediatria/chapter/B42.166.1.
[2] Gamaldo, C. E. et al. (2012). The sleep-immunity relationship. Neurologic clinics, 30(4), s. 1313–1343. https://doi.org/10.1016/j.ncl.2012.08.007
[3] Nieman, D. C., Wentz, L. M. (2019). The compelling link between physical activity and the body's defense system. Journal of sport and health science, 8(3), s. 201–217. https://doi.org/10.1016/j.jshs.2018.09.009
[4] Nieman D. C. (2003). Current perspective on exercise immunology. Current sports medicine reports, 2(5), s. 239–242. https://doi.org/10.1249/00149619-200310000-00001
[5] Seiler, A. et al. (2019). The Impact of Everyday Stressors on the Immune System and Health. Stress Challenges and Immunity in Space, s. 71-92. https://doi.org/10.1007/978-3-030-16996-1_6
[6] Ginde, A. A. et al. (2009). Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Archives of internal medicine, 169(4), s. 384–390. https://doi.org/10.1001/archinternmed.2008.560
[7] Jolliffe, D. A. et al. (2021). Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of aggregate data from randomised controlled trials. The Lancet: Diabetes & Endocrinology, 9(5) s. 276-292. https://doi.org/10.1016/S2213-8587(21)00051-6
[8] Carr, A. C., Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, 9(11), s. 1211. https://doi.org/10.3390/nu9111211
[9] Gammoh, N. Z., & Rink, L. (2017). Zinc in Infection and Inflammation. Nutrients, 9(6), s. 624. https://doi.org/10.3390/nu9060624
[10]Martinez-Estevez, N. S. et al. (2016). Effects of zinc supplementation in the prevention of respiratory tract infections and diarrheal disease in Colombian children: A 12-month randomised controlled trial. Allergologia et immunopathologia, 44(4), s. 368–375. https://doi.org/10.1016/j.aller.2015.12.006
[11] Singh, M., Das, R. R. (2013). Zinc for the common cold. The Cochrane database of systematic reviews, 6. https://doi.org/10.1002/14651858.CD001364.pub4
[12] Chang, J. P. et al. (2020). Omega-3 fatty acids in the psychological and physiological resilience against COVID-19. Prostaglandins, leukotrienes, and essential fatty acids, 161, 102177. https://doi.org/10.1016/j.plefa.2020.102177
[13] Shakoor, H. et al. (2021). Immune-boosting role of vitamins D, C, E, zinc, selenium and omega-3 fatty acids: Could they help against COVID-19?. Maturitas, 143, s. 1–9. https://doi.org/10.1016/j.maturitas.2020.08.003