How to improve immunity?

Autumn and winter are the two seasons that are usually associated with the highest number of colds and flu infections. There are many factors that affect our body's immunity, namely diet and supplementation, physical activity, sleep, stress, relaxation and rest, medications, stimulants, age, chronic diseases, gut microbiota, body fat content and genetics. So let's find out how you can effectively improve your body's immunity.

• Eat fresh, multi-colored vegetables and fruits every day
• Follow a rational and varied diet
• Include probiotic foods in your diet
• Regularly engage in physical activity
• Consistently supplement vitamin D

Eat fresh, multi-colored vegetables and fruits every day

Vegetables and fruits are rich sources of many vitamins, minerals and antioxidants, as well as dietary fiber with prebiotic properties, i.e. stimulating the selective growth and activity of beneficial microorganisms in the gut. Adequate supply of these valuable nutrients ensures the proper functioning of the body, including the proper functioning of the immune system. It is particularly important to regularly include in the diet a variety of colorful fresh vegetables and fruits, which are abundant in vitamin C and provitamin A, or β-carotene. Vitamin C is an antioxidant that has a well-documented effect of neutralizing the harmful effects of reactive oxygen species and inhibiting the oxidation of lipids, proteins, carbohydrates and nucleic acids. In addition, vitamin C supports the activity of many immune system cells, shortens the duration of upper respiratory tract infections (especially the common cold) and significantly reduces the risk of pneumonia, especially in people with low dietary intake. Beta-carotene also exhibits strong antioxidant properties, scavenging oxygen free radicals, excess of which can lead to the development of cardiovascular, cancer, neurodegenerative and ophthalmic diseases, as well as type 2 diabetes. Βeta-carotene is also involved in the formation of vitamin A in the body, which is responsible for the proper functioning of the immune system.

Follow a rational and varied diet

It is in vain to look for just one food to provide all the nutrients necessary for the body to function properly, which is why it is so important to follow a varied diet. To improve immunity, you should regularly include in your diet products with high nutritional value, such as vegetables and fruits, coarse grains, legumes, fermented dairy products, fish (especially fatty species), lean poultry meat, eggs and healthy vegetable fats (including: nuts, sunflower seeds, flaxseeds, pumpkin seeds, extra virgin olive oil, cold pressed canola oil and avocado oil). A varied diet following the recommendations presented in the form of a healthy diet plate provides all the nutrients needed for the proper functioning of the immune system. We are talking primarily about long-chain omega-3 polyunsaturated fatty acids (especially EPA and DHA), antioxidant vitamins (A, C and E), B vitamins, vitamin D and minerals such as magnesium, zinc, iron, copper and selenium. A diet rich in multi-colored fresh fruits and vegetables also provides a wide variety of bioactive compounds, and already especially carotenoids and polyphenols, which inhibit oxidative stress and inflammation, and have antimicrobial and prebiotic effects, so they support the proper functioning of the immune system.

Include probiotic foods in your diet

To improve immunity, it's also a good idea to include low-fat fermented dairy products (including: natural yogurts, kefirs, buttermilk, acidophilic milk, cottage cheese) and pickled vegetables (e.g. cucumbers, cabbage, beets, carrots, garlic)in your daily diet. These products contain strains of probiotic bacteria from the genus Lactobacillus and Bifidobacterium, which strengthen the body's immunity, inhibit the growth of pathogenic microorganisms, regulate the gastrointestinal tract and favorably influence the composition and metabolic activity of the intestinal microbiota.

Regularly engage in physical activity

Available evidence suggests that regular physical activity has a beneficial effect on improving immunity and preventing various bacterial or viral infections. Systematic exercise of moderate intensity has been shown to reduce the risk of upper respiratory tract infections, compared to leading a sedentary lifestyle. According to available meta-analyses, regular physical activity is associated with a 31% lower risk of developing infectious diseases and a 37% lower risk of mortality from infectious diseases.

Consistently supplement vitamin D

Vitamin D has well-documented anti-inflammatory and immunomodulatory properties. Studies have shown that vitamin D can help reduce the severity of inflammation, and even more so in patients diagnosed with type 2 diabetes and heart failure. Vitamin D also supports the activity of several immune system cells and stimulates the production of antimicrobial proteins such as cathelicidin and β-defensin**. Ongoing vitamin D supplementation during the fall and winter, or even year-round (in the absence of sufficient sunlight exposure during the summer months), may reduce the incidence of upper respiratory tract infections.

Sources:

• Mitra S, Paul S, Roy S, et al: Exploring the Immune-Boosting Functions of Vitamins and Minerals as Nutritional Food Bioactive Compounds: A Comprehensive Review. Molecules. 2022 Jan 16;27(2):555.

• Junaid K, Ejaz H, Abdalla AE, et al: Effective Immune Functions of Micronutrients against SARS-CoV-2. Nutrients. 2020 Sep 29;12(10):2992.

• Shao T, Verma HK, Pande B, et al: Physical Activity and Nutritional Influence on Immune Function: An Important Strategy to Improve Immunity and Health Status. Front Physiol. 2021 Oct 8;12:751374.

• Calder PC.: Foods to deliver immune-supporting nutrients. Curr Opin Food Sci. 2022 Feb;43:136-145.

• Childs CE, Calder PC, Miles EA.: Diet and Immune Function. Nutrients. 2019 Aug 16;11(8):1933.