How to Boost Your Immune System Naturally? Vitamins and Supplements for Adults and Kids

September means a return to preschool, school, and the office - and with it, the first runny noses and coughs. Fall and winter are the seasons when our bodies may need extra support. It’s no surprise that parents and adults ask the same question every year: how can you boost your immune system naturally? While a balanced diet, enough sleep, and regular physical activity form the foundation of good health, carefully chosen immune support vitamins and supplements can complement these everyday habits. Below, you’ll find a guide to some of the best vitamins and immune support supplements. Learn how to strengthen your immune system safely and support the whole family.

The immune system is a complex network of vessels, organs (including the spleen, thymus, and lymph nodes), cells, and antibodies that protect the body from external threats such as viruses and bacteria. It works on two levels: innate immunity, which acts as the first line of defense, and acquired immunity, which creates immune memory. Few people realize that a large part of the immune system is located in the gut. It is estimated that around 70% of immune cells are found there, which is why what we eat can have a direct impact on immune function.

Before reaching for supplements, it is worth looking at how to boost your immune system naturally from the ground up. Four pillars of a healthy lifestyle are especially important:

• Balanced diet: Provides protein, healthy fats, and essential vitamins and minerals. Fruits and vegetables are sources of vitamin C and polyphenols, fatty fish provide omega-3 fatty acids, and fermented foods, kefir, and plain yogurt contain live bacterial cultures that support the gut microbiota.
• Adequate sleep and recovery: Sleep supports the proper functioning of the nervous system and the body’s recovery processes. Adults are generally advised to get 7–9 hours of sleep, while children need more depending on age.
• Physical activity: Moderate, regular exercise, preferably outdoors, supports circulation and overall health.
• Stress management: Chronic stress can affect immune function, so regular rest and recovery are important.

Supplements can be a useful addition to the daily diet when nutrient needs are increased or certain deficiencies are present. When diet alone does not fully meet the body’s needs, carefully selected immune support vitamins and an immune support supplement may help complement everyday nutrition.

Carefully selected nutrients play a fundamental role in the normal functioning of the immune system. When choosing immune support supplements, it is worth paying attention to ingredients with authorized health claims.

Vitamin D is a steroid prohormone that affects the functioning of almost the entire body. As much as 70-80% of vitamin D3 in our body is formed in the skin under the influence of sunlight, while food sources such as fatty fish and eggs provide only part of our needs.

In the United States, vitamin D production in the skin depends on factors such as season, latitude, time spent outdoors, age, skin pigmentation, and sun exposure. People who get little sun exposure may be at greater risk of having low vitamin D levels.

According to official guidance, vitamin D:

• supports normal immune function;
• helps the body absorb calcium;
• supports healthy bones and muscles.

In the U.S., the recommended daily amount of vitamin D is 15 mcg (600 IU) for children age 1 and older and adults up to age 70, and 20 mcg (800 IU) for adults age 71 and older. Infants up to 12 months need 10 mcg (400 IU) per day.

Vitamin C (L-ascorbic acid) is one of the most important micronutrients in the daily diet. The body is unable to produce it or store it, which is why we need it every day. According to approved claims, vitamin C:

• Helps in the proper functioning of the immune system.
• Helps in the protection of cells against oxidative stress (acts as a strong antioxidant).
• Contributes to the reduction of the feeling of fatigue and tiredness.
• Helps in the proper production of collagen for the purpose of ensuring the proper functioning of blood vessels, bones, cartilage, gums, skin, and teeth.

Vitamins A, D, E, and K dissolve in fats, which is why it is best to take them with a meal. The ADEK complex offers comprehensive support:

• Vitamin A: Helps in the proper functioning of the immune system and helps maintain the proper condition of mucous membranes and healthy skin.
• Vitamin D: Helps in the proper functioning of the immune system and in maintaining healthy bones.
• Vitamin E: Helps in the protection of cells against oxidative stress.
• Vitamin K: Contributes to proper blood clotting and helps in maintaining healthy bones.

Comprehensive preparations make it easier to balance the diet, especially for picky eaters, seniors, and people on elimination diets. A very important element of such formulations is zinc. According to health claims, zinc:

• Helps in the proper functioning of the immune system.
• Helps in the protection of cells against oxidative stress.
• Participates in the process of cell division and helps in the proper synthesis of protein and DNA.

In addition to basic vitamins, it is worth considering other ingredients that can complement the diet. For adults looking for immune support, supplements with ingredients such as bovine colostrum, omega-3s, probiotics, quercetin, or turmeric may be worth considering, depending on individual needs and the overall formulation.

Dietary supplements combining omega-3 fatty acids (EPA and DHA) with vitamin D can provide support for several important functions in the body. Since many people do not eat fatty fish regularly, omega-3 supplements can be a practical way to complement the diet.

EPA and DHA support normal heart function, while DHA also helps support normal brain function and vision. Vitamin D supports the normal function of the immune system, which is why this combination may be relevant for people looking for additional immune support and wondering how to strengthen the immune system.

Since a large proportion of immune cells are located in the gut, supporting the gut microbiota is one of the most logical steps. Probiotics used for immune support are live microorganisms that help maintain a balanced gut microbiota. Their effects depend on the specific strain, so it is worth choosing products with clearly identified strains and a formulation suited to individual needs.

Quercetin is a natural plant flavonoid with antioxidant potential, present, among others, in onions, apples, and capers. In supplements, it is often combined with bromelain (an enzyme from pineapple) and vitamin C, which helps protect cells against oxidative stress and supports the proper functioning of the immune system.

Turmeric extract is rich in curcumin with antioxidant properties. Curcumin is naturally poorly absorbed, which is why it is worth choosing preparations with piperine (black pepper extract), which increases its bioavailability. Due to its intense taste, adults most often reach for turmeric in capsules.

Both vitamins and immune support supplements should be chosen in age-appropriate forms to ensure safe and convenient use:

Sources:

Vitamins and U.S. recommendations

• National Institutes of Health, Office of Dietary Supplements (NIH ODS). Vitamin D – Fact Sheet for Health Professionals.
  https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

• National Institutes of Health, Office of Dietary Supplements (NIH ODS). Omega-3 Fatty Acids – Fact Sheet for Health Professionals.
  https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/

Bovine Colostrum

• Guberti M., Botti S., Capuzzo M.T., Nardozi S., Fusco A., Cera A., Dugo L., Piredda M., De Marinis M.G. (2021). Bovine Colostrum Applications in Sick and Healthy People: A Systematic Review. Nutrients, 13(7), 2194.
  https://doi.org/10.3390/nu13072194

• Jones A.W., March D.S., Curtis F., Bridle C. (2016). Bovine colostrum supplementation and upper respiratory symptoms during exercise training: a systematic review and meta-analysis of randomised controlled trials. BMC Sports Science, Medicine and Rehabilitation, 8, 21.
  https://doi.org/10.1186/s13102-016-0047-8

Turmeric and Curcumin

• Hewlings S.J., Kalman D.S. (2017). Curcumin: A Review of Its Effects on Human Health. Foods, 6(10), 92.
  https://doi.org/10.3390/foods6100092

• Montanino C., Farinella F., De Felice B., Del Buono A., D’Orta A. (2025). The Potential Systemic Anti-Inflammatory Effect of Turmeric Dried Extract. Endocrine, Metabolic & Immune Disorders - Drug Targets, 25(14), 1191–1198.
  https://doi.org/10.2174/0118715303329562241116045410

• Allegra A., Mirabile G., Ettari R., Pioggia G., Gangemi S. (2022). The Impact of Curcumin on Immune Response: An Immunomodulatory Strategy to Treat Sepsis. International Journal of Molecular Sciences, 23(23), 14710.
  https://doi.org/10.3390/ijms232314710

Omega-3 Fatty Acids

• Bodur M., Yilmaz B., Ağagündüz D., Ozogul Y. (2025). Immunomodulatory Effects of Omega-3 Fatty Acids: Mechanistic Insights and Health Implications. Molecular Nutrition & Food Research, 69(10), e202400752.
  https://doi.org/10.1002/mnfr.202400752

Probiotics

• Mazziotta C., Tognon M., Martini F., Torreggiani E., Rotondo J.C. (2023). Probiotics Mechanism of Action on Immune Cells and Beneficial Effects on Human Health. Cells, 12(1), 184.
  https://doi.org/10.3390/cells12010184

• Yan F., Polk D.B. (2011). Probiotics and immune health. Current Opinion in Gastroenterology, 27(6), 496–501.
  https://doi.org/10.1097/MOG.0b013e32834baa4d

Quercetin

• Formica J.V., Regelson W. (1995). Review of the biology of Quercetin and related bioflavonoids. Food and Chemical Toxicology, 33(12), 1061–1080.
  https://doi.org/10.1016/0278-6915(95)00077-1

Immune System and Gut

• Vighi G. et al. (2008). Allergy and the gastrointestinal system. Clinical and Experimental Immunology, 153(Suppl 1), 3–6.
  https://doi.org/10.1111/j.1365-2249.2008.03713.x