Listen to the podcast interview I did on natural immune system support with Roxanne from Simply Kids Wellness here.
There are some key nutrients that the body’s immune system requires in order to do its job of protecting the body from infections. Exposure to certain elements can also suppress the function of the immune system. When we are aware of these factors, we can then choose to support our immune systems with foods that contain these nutrients and specific foods that have immune boosting or anti-viral properties and we can minimise factors that suppress immune function.
Vitamin C is required for immune function and to reduce susceptibility to infections.
Adequate vitamin C needs to be consumed for the immune system to function well. Immunity is impaired when there is a deficiency of vitamin C, leading to an increased susceptibility to infections . Vitamin C supplementation seems to be able to prevent and treat respiratory and systemic infections . Vitamin C concentrations in the blood plasma quickly decline during infections  due to inflammatory and metabolic requirements  thus increasing the body’s requirements for vitamin C .
Supplementation of vitamin C has been found to improve elements of the immune system, such as antimicrobial and natural killer (NK) cell action, lymphocyte proliferation (white blood cells especially in the lymphatic system), chemotaxis and delayed-type hypersensitivity (allergic immune reaction) .
When utilising vitamin C to prevent infection, the dosage amount needs to be able to offer adequate to saturated blood plasma levels to optimise cell and tissue levels. This amount may be 100-200mg/day in adults . When there is an infection already present, the amount of vitamin C intake required to compensate for the increased inflammation and metabolic demand increases to a higher dose in the grams.
Food Sources of Vitamin C: Citrus fruits - oranges, lemons, limes; broccoli, brussel sprouts. kiwi fruit, fruits, vegetables, red and green capsicum, broccoli, aloe vera juice, parsley, tomatoes, potatoes, raw cabbage, sweet potatoes.
Vitamin C is destroyed by cooking so eat these foods raw or lightly steamed to maximise your vitamin C ingestion. Light exposure can also destroy vitamin C.
Zinc is required for immune function.
Zinc is required for more than 300 enzymatic processes in the body. These processes have an effect on the function of bodily organs and also a secondary effect on the immune system .
Adequate zinc levels in the body are required for immune function. A deficiency of zinc has been shown to impair cellular mediators of innate immunity such as phagocytosis and NK cell activity . Zinc has a direct effect on the production, maturation and function of white blood cells (leukocytes) .
Zinc and vitamin C are both crucial to immune function to reduce the risk, severity and duration of infectious disease . When there is adequate intake of vitamin C and zinc, there can be an improvement in the symptoms and shortened duration of respiratory tract infections .
Food Sources of Zinc: capsicum, nuts such as cashews and almonds, seeds: pumpkin, sunflower and sesame seeds; meat, egg yolks, ginger, legumes such as chickpeas- sprout or soak chickpeas to reduce phytates which reduce mineral absorption.
Maximise Nutrients in Your Food
Certain vitamins and minerals are susceptible to destruction via conditions such as: heating, light, milling (of grains), freezing, cooking, canning.
When preparing your meals, try these methods to minimise nutrient loss:
- Lightly steamed
- Lightly stir-fried in water
Mushrooms may support immune function.
Mushrooms contain a constituent called beta-glucan, and beta-glucan has been found to have a supportive effect on the immune system. Beta-glucans increase host immune defence by activating complement system (part of the immune system that enhances clearance of microbes and damaged cells amongst other actions), enhancing macrophages and NK cell function .
Garlic may be used in the prevention and treatment of viral infections.
Garlic contains many constituents, one of which is known as active organosulfur compounds (OSCs). Garlic has been studied for its many health benefits, one of which is its effect on the immune system. Garlic and its OSCs have an immunomodulatory effect that has been linked to an improvement of viral infection . Garlic has been demonstrated to be of use in prevention of widespread viral infections through an enhancement of the immune response . Garlic has significant antiviral activity .
Probiotics and Prebiotics
Probiotics are live organisms, usually bacteria, and contribute to a healthy microbiome. Prebiotics are special types of plant fibres that stimulate the growth of healthy bacteria in the gut.
For overall health including immunity, including foods that are particularly high in pre and probiotics may be of benefit.
A large portion of our immune system resides in our gut. In the lumen and upper part of the mucus layer of the gastrointestinal tract (GIT) lives an abundance of microorganisms. These microorganisms create a micro-ecosystem called the microbiome. The composition of these microorganisms have an effect on the gut barrier and gut immune system , as well as our overall health, mood and much more.
Probiotics may help with intestinal barrier integrity as well as modulation of the immune system. Probiotics may modulate the immune system by increasing the action of NK cells and macrophages, modulate the secretion of cytokines or immunoglobulins, or by improving gut barrier integrity .
Specific species and strains of probiotics have specific effects , this is of particular importance when you are wanting to utilise probiotics for specific therapeutic outcomes. It seems that the timing of intervention with probiotics is important, with possibly the greatest effects earlier in life .
Food sources of probiotics: kim chi, sauerkraut, good quality yoghurt (check for probiotic count and less than 10grams of sugar per serve) - natural rather than flavoured yoghurts tend to be lower in sugar.
Food sources of prebiotics: fruits, vegetables, especially those that contain complex carbohydrates such as fibre and resistant starch. As these types of carbohydrates are not digestible by the body, they pass through the digestive system and the microbes consume them. Garlic, onions, bananas, oats, apples to name a few.
Our bodies restore, rebuild, recover and process when we are asleep. Adequate sleep is required for health and good immune function. A gentle and predictable evening routine can help with the wind down into sleep, this essentially trains the body with what to expect. The body loves routine and regularity, our systems function better when the body knows what to expect, and this also includes eating at the same or similar times each day.
When high levels of sugar enter the bloodstream, it can significantly alter immune response and leave the body more susceptible to infection . If children are consuming sugar consistently throughout the day, their immune activity is consistently reduced hence they may be more susceptible to infections.
According to the American Academy of Pediatrics, their website recommends to “aim for less than 25 grams (about 6 teaspoons) of added sugar per day for children 2 years of age and older. Avoid serving food and drinks with added sugar to children under 2 years of age.”  Personally I aim for less than this, especially with younger children. For adults a good guide is less than 10g of sugar per serve, and much less than this for children, especially younger children.
The World Health Organisation recommends up to six teaspoons of sugar for women per day, and that's for an adult. It seems reasonable to ensure children are having less than this.
When the stress response is activated, the immune activity is reduced leaving the person more susceptible to infection. When we experience stress, the ideal natural follow up is a period of rest and recovery from the feeling of stress. It is common for many of us that we stress a lot with minimal down time.
If we can minimise the time we are experiencing the stress response, then we may reduce not only the feeling of stress but also the amount of time that immune activity is reduced, which can last for some time after we feel stressed.
For our children we can create a calm, safe environment for them to be in, and with our own stress management techniques too, we can model not only how we behave when we are stressed, but how we return to a state of calm and neutrality.
Routine practices that are calming, they may or may not be so purposeful. For example, a sit down deep breathing practice. Or a coming together to relax by the fire and enjoy each other’s company or read a book.
Immunity Snacks and Meal Ideas
· Freshly squeezed orange and lemon juice
· Bliss balls made with almonds, cashew and pepitas
· Chicken and vegetable soup, add fresh broccoli, leafy greens and chopped brussel sprouts and cook these for the last 5 or so minutes for a nutrition boost. Stir through fresh garlic to serve, add fresh parsley for even more vitamin C.
To actively support yours and your family’s immune systems, focus on whole fresh foods that are especially good sources of vitamin C, zinc and probiotics, add in some mushrooms and fresh garlic for an added benefit. Minimise sugar and sugar containing foods, read the labels of packaged foods to know how much sugar they contain and include some relaxing down time as part of your family’s daily routine. Create relaxing routines in the evening that lead you and your children gently into a relaxed state to support sleep and when unwell, listen to the body’s cues and take that extra nap.
1. Carr, A. C., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, 9(11), 1211. https://doi.org/10.3390/nu9111211
2. Wintergerst, E. S., Maggini, S., & Hornig, D. H. (2006). Immune-enhancing role of vitamin C and zinc and effect on clinical conditions. Annals of nutrition & metabolism, 50(2), 85–94. https://doi.org/10.1159/000090495
3. Rink, L., & Gabriel, P. (2000). Zinc and the immune system. The Proceedings of the Nutrition Society, 59(4), 541–552. https://doi.org/10.1017/s0029665100000781
4. Akramiene, D., Kondrotas, A., Didziapetriene, J., & Kevelaitis, E. (2007). Effects of beta-glucans on the immune system. Medicina (Kaunas, Lithuania), 43(8), 597–606.
5. Rouf, R., Uddin, S. J., Sarker, D. K., Islam, M. T., Ali, E. S., Shilpi, J. A., Nahar, L., Tiralongo, E., & Sarker, S. D. (2020). Antiviral potential of garlic (Allium sativum) and its organosulfur compounds: A systematic update of pre-clinical and clinical data. Trends in food science & technology, 104, 219–234. https://doi.org/10.1016/j.tifs.2020.08.006
6. La Fata, G., Weber, P., & Mohajeri, M. H. (2018). Probiotics and the Gut Immune System: Indirect Regulation. Probiotics and antimicrobial proteins, 10(1), 11–21. https://doi.org/10.1007/s12602-017-9322-6
7. Frei, R., Akdis, M., & O'Mahony, L. (2015). Prebiotics, probiotics, synbiotics, and the immune system: experimental data and clinical evidence. Current opinion in gastroenterology, 31(2), 153–158. https://doi.org/10.1097/MOG.0000000000000151
8. Jafar, N., Edriss, H., & Nugent, K. (2016). The Effect of Short-Term Hyperglycemia on the Innate Immune System. The American journal of the medical sciences, 351(2), 201–211. https://doi.org/10.1016/j.amjms.2015.11.011
Korioth, T. (March 25, 2019) Added sugar in kids’ diets: How much is too much? AAP News Retrieved on 9th June, 2021 from: https://www.aappublications.org/news/2019/03/25/sugarpp032519