Our immune system is our basic defense system against infections. It plays an essential role in maintaining our overall health by protecting our bodies from harmful microorganisms. Immune system stress is an important topic today.
Research suggests that chronic stress may have a significant impact on our overall health by interfering with our immune function.
The aim of this article is to explore the role that stress plays in immunity and to highlight the best ways to boost this complex system under conditions of stress.
The Impact of Stress on Immune Function
Research suggests that daily stresses in childhood, adolescence, and or adulthood, negatively impact our health by down-regulating our immune systems. 
Under conditions of stress, our bodies release a “stress hormone” called cortisol. 
You may have heard of it…
Cortisol plays an important role in making sure our immune system functions efficiently. It does so by reducing inflammation and ultimately acting as our immune systems ‘off’ switch.
The problem is, we often experience increased levels of stress from many different factors such as increased work pressure, poor sleeping patterns, emotional changes, excessive exercise, and smoking. Sometimes this can last for months or years.
Over time, our immune systems may become suppressed from these elevated cortisol levels, leaving us vulnerable to infection and disease.
Luckily, a few lifestyle changes have shown promise in naturally strengthening our immune systems and providing immune system stress support.
Boosting the Immune System
Research suggests that there are five important ways to help strengthen your immune system during times of stress. These include:
- Adequate sleep
- Regular exercise
- Healthy food choices
- Dietary supplements
- OTC / pharmaceutical options.
Sleep and the Immune system
Emerging evidence suggests the chronic sleep loss may have a detrimental effect on our immune system. A loss of sleep of up to 48 hours was found to result in a noticeable decrease in immune cell production and activity.
Furthermore, clinical trials have found an association with sleep loss and increased cortisol levels. 
As we now know, increased levels of the stress hormone, cortisol, can cause our immune systems being to be continually suppressed.
So, evidence points towards the importance of adequate sleep for a healthy immune system. Most doctors recommend around 7 – 9 hours of sleep per night, for an adult. Sleep Foundation.org is a great resource for information on how to improve your sleep – made up of a multidisciplinary expert panel.
They have resources for people who struggle to fall asleep due to a number of reasons. If you find your immune system is underperforming, you may want to look into your sleep habits!
- Sleep is vital for a healthy immune system
- Adults require 7 – 9 hours sleep per night
- Try sleep therapy, sleep supplements, or see a sleep doctor to help improve your sleep and support your immune system.
Foods for a Healthy Immune System
Good nutrition is an essential factor in maintaining a healthy immune system. The human gut plays an essential role in immunity with the large intestine, also known as the colon, being the largest immune organ in the human body. 
Research suggests that some nutrients have very specific roles in the development and maintenance of an effective immune system.  Under conditions of stress, the demand for nutrients including zinc, vitamin A, selenium, vitamin D, and glutamine is increased.
Therefore, it is important to include foods that are rich in these nutrients – especially in times of stress.
One of the biggest challenges with stress is that it has been shown to lead to unhealthy food choices, reducing our overall diet quality when our immune systems need it the most. 
A balanced diet, rich in plant-based foods including fruits and vegetables (at least 5 servings per day) has been found to improve immune function. Fruits and vegetables contain significant amounts of micronutrients essential for supporting our immune systems including vitamin A and selenium.
It is clear that certain nutrients have a key influence on our immune systems. The next step is to ensure our intake of these nutrients is met on a day to day basis.
Here are some ideas of healthy foods to include in your diet to support a strong immune system in times of stress:
- Green vegetables
- Leafy vegetables
- Sweet potatoes
- Citrus fruits
Supplements for a Healthy Immune System
Zinc, vitamin A and glutamine are especially important micronutrients for supporting a healthy immune system.
They play an essential role in cell division and are key nutrients that enable our bodies to produce sufficient immune cells.
Furthermore, glutamine acts as an important energy source for cells involved in the immune response. Studies have shown that glutamine is an essential nutrient not only for the production of immune cells but for the signaling and activity of immune cells too. 
Aside from these nutrients from food, you may wish to include a multivitamin or dietary supplement immune support in your diet. Try to choose from a multivitamin that contains the above-mentioned micronutrients (zinc, vitamin A, vitamin D, and selenium) for optimal immune support.
Below are some interesting additional vitamins, elements, and plant extracts that may help support your immune system even further:
- Selenium is a trace element that acts as a powerful antioxidant. Clinical trials have shown that increasing selenium intake is associated with an overall enhanced immune response. 
- Vitamin D is a fat-soluble vitamin with the primary role of assisting our immune cells to function properly. In cases of vitamin D deficiencies, the risk of infection has been shown to be notably increased.
- Quercetin – a dietary supplement found in many fruits and vegetables with powerful antioxidant and anti-inflammatory effects.
- Baicalin – extracted from the Blue Skullcap plant, Baicalin has been used in TCM for hundreds of years and has been extensively researched for its benefits on the immune system and as an antiviral supplement.
- Andrographis Paniculata extract – a Sri Lankan herb commonly known as creat or green chireta is gaining popularity around the world for its benefits on the immune system.
To read more about how you can use supplements to support your immune system, check out our blog post here.
Exercise and the Immune system
Research today suggests that our immune systems are very responsive to exercise. Daily exercise has been associated with an overall reduced risk of infection.
Interestingly, each exercise session has been found to cumulatively enhance immune function – highlighting the relationship between immune system stress and exercise. 
Doctors typically recommend at least 30 minutes of moderate exercise per day – for example, swimming, biking, yoga, hiking, or other low impact exercises.
If you are younger and more active, you may require a better workout to stimulate your immune system. Research has indicated the high-intensity interval training (HIIT) is great for stimulating the immune system – and potentially better than prolonged aerobic exercises like long-distance running or swimming.
There are plenty of resources on HIIT exercise – for all different fitness levels and body types.
Importantly though, it is good to remember not to overdo it with your exercise. Excessive exercise can temporarily reduce the immune system function. Research has shown that up to 90 minutes of intensive exercise can increase your cortisol and adrenalin levels for 72 hours, reducing immune function.
- At least 30 minutes of moderate, low impact exercise per day
- For fitter people, try including a HIIT-type workout to kick start the immune system
- Avoid prolonged intensive exercise over 45 minutes, as it may temporarily reduce your immune system
The Gut Microbiome & Immunity
Researchers believe that the human gut is home to at least 100 trillion microbial cells – an order of magnitude greater than the number of human cells on your body!
In fact, you could say that there are approximately 10 times more microbial cells in the human body than human cells, and the collective gut microbial genome is at least 150 times larger than the human genome. 
Research from the early 2000s has focused on the relationship between human and microbial cells. It is now understood that there was a symbiotic relationship in our evolution and that the gut microbes we carry with us evolved with us along the way.
So, what does that have to do with immunity?
Well, the human gut and the immune system work together to promote a healthy body. The gut microbiome releases immunity cells called helper T-cells, which assist antibodies with tracking and destroying pathogens and toxins in our bodies. 
The immune system also communicates with the gut microbiome by assisting the growth of symbiotic microbes. In return, the gut microbiome helps to develop enzymes required for a healthy immune response.
It’s a win-win relationship.
For more information on how the gut influences immune system stress, check out our blog post here!
If you’re wondering how to optimize your gut microbiome to improve your immune system during times of stress, here are a few suggestions:
- Cut out processed foods from your diet
- Include more prebiotic fiber – from vegetables and legumes
- Include prebiotic foods like kefir, sauerkraut, and yogurt
- Try taking a prebiotic supplement
Vaccines and Immunization
While natural options and lifestyle changes are typically the go-to advice for immune system stress support, these are not always sufficient to completely prevent getting an infection. Some pathogens are too strong for our immune system and can wreak havoc in our bodies, no matter how healthy we are.
That’s why we have vaccines.
Vaccines are biological preparations designed to produce an acquired immunity to a pathogen – usually a virus. Around the world, we have eradicated one major disease – smallpox – and all but eradicated polio. 
In the United States, several diseases have almost been eradicated, including measles, bacterial influenza, measles, mumps, rubella, and tetanus. In fact, the World Health Organization lists 25 vaccines that are proven to be effective against human diseases.
Nevertheless, there has recently been a counter-movement against vaccines, fuelled by a number of different beliefs, ranging from fear of allergies to elaborate conspiracy theories. It is important to remember that vaccines save millions of lives each year – approximately 3 million – and a further 1.5 million deaths could be saved if all recommended vaccines were used.
While there is a very small chance of an allergy or negative reaction to a vaccine (approximately one in a million) the risks of not being vaccinated are far greater – not only for the person who isn’t vaccinated but also for the population surrounding that person.
- Vaccines provide an acquired immunity for over 25 preventible diseases
- Immunization is a safe way to reduce your chances of acquiring a preventable disease
- Vaccinations protect not only the person getting the vaccine but also the surrounding community
OTC and Pharmaceutical Options for Immune Disorders
For most people, getting enough sleep, exercising regularly, eating healthily, staying immunised, and supporting a healthy gut microbiome is more than enough to promote a healthy immune system – even during times of stress.
However, if you have an immune disorder – for example, a compromised immune system or an overactive immune system, you may need to get medical treatments for extra support in stressful times.
Examples of autoimmune diseases, where the immune system malfunctions and ‘attacks’ cells in your own body, include:
- Rheumatoid arthritis
- Type 1 diabetes
- Multiple sclerosis
- Inflammatory bowel disease
- Celiac disease
- Guillain-Barre syndrome
- Grave’s disease
- Hashimoto’s thyroiditis 
Therapies for these diseases typically include a range of pharmaceuticals, often involving non-steroidal anti-inflammatory drugs (NSAIDs), steroids, and/or drugs that help to decrease the immune system’s activity.
Examples of diseases that compromise the immune system, reducing its ability to work and leaving the patient susceptible to infections, include:
- X-linked agammaglobulinemia (XLA)
- common variable immunodeficiency (CVID)
- severe combined immunodeficiency (SCID)
- complications from severe burns, chemotherapy, diabetes, radiation, or malnutrition
- viral hepatitis
- multiple myeloma 
Treatments for these diseases depends on the underlying condition. Typically, drugs like antibiotics, antiviral and anti-fungal medications are given for each infection.
Immunoglobulin therapy and antiretroviral drugs may also be used. In severe cases, bone marrow transplants might be ordered.
- Most people have a normal immune system and do not need medical treatments
- In case you have an immune disorder or a compromised immune system, your doctor will inform you of the next steps and the appropriate medications.
The Immune System & Age
As we get older, our immune systems begin to lose some of their potency, increasing the risk of disease and cancer. This is why countries with higher life expectancies tend to have a greater incidence of age-related conditions.
Research indicates that, compared to young people, older persons are more likely to contract infectious diseases, and are also more likely to die from them.
On an immune level, the body starts to reduce the production of helper T cells and B cells (also known as primary lymphocytes) as we age. This is thought to be due to changes in stem cells, local tissue, and systemic environments, and it results in an increased occurrence of immune system stress. 
The leading causes of death of people over the age of 65 tend to be heart disease, cancer, strokes, and respiratory diseases. 
Around the world, researchers are working on potential therapies to combat the decline in immune function in the elderly. One leading theory has to do with a form of malnutrition, especially in wealthy countries where life expectancy is high.
This is micronutrient deficiency – in which a person becomes deficient in essential vitamins or trace minerals as a result of their diet. Micronutrients act as cofactors for enzymes and are vital for a healthy, strong immune system. As older people tend to eat less varied diets, they may risk becoming deficient in certain micronutrients, which can negatively impact the immune system. 
- As we age, our immune system function starts to decline
- This is linked to reduced production of B-lymphocytes and helper T-cells
- Micronutrient deficiency is thought to play an important role in the immune decline in older persons
In summary, a functioning immune system is essential in protecting us from illness and disease.
Today, on-going stress is recognized as a key risk factor for increasing the likelihood of developing a disease, due to its effect in dampening our immune systems.
It is essential for us to make healthy lifestyle changes in order to boost our immune systems as much as possible.
Key strategies to reduce immune system stress include adequate sleep, regular exercise, immunization, and good nutrition.
Research has revealed that increasing intakes of specific nutrients including zinc, vitamin A, selenium, vitamin D, and glutamine, may significantly enhance immune function.
To increase levels of these nutrients consumed, a balanced diet rich in fruits and vegetables is recommended. In conjunction with a healthy diet, a daily multivitamin containing these micronutrients should also be considered, especially during times of increased stress.
Given the immune-enhancing effects of adequate sleep, regular exercise, and good nutrition, these factors should collectively be recognized as fundamental parts of our immune systems.
 Morey, J. N., Boggero, I. A., Scott, A. B., & Segerstrom, S. C. (2015). Current Directions in Stress and Human Immune Function. Current opinion in psychology, 5, 13–17.
 Ranabir, S., & Reetu, K. (2011). Stress and hormones. Indian journal of endocrinology and metabolism, 15(1), 18–22.
 Bryant, P. A., Trinder, J., & Curtis, N. (2004). Sick and tired: does sleep have a vital role in the immune system? Nature Reviews Immunology, 4(6), 457–467.
 Minkel, J., Moreta, M., Muto, J., Htaik, O., Jones, C., Basner, M., & Dinges, D. (2014). Sleep deprivation potentiates HPA axis stress reactivity in healthy adults. Health Psychology, 33(11), 1430–1434
 Chassaing, B., Kumar, M., Baker, M. T., Singh, V. and Vijay-Kumar, M. (2014). Mammalian gut immunity. Biomedical journal, 37(5), 246–258.
 Childs, C. E., Calder, P. C., & Miles, E. A. (2019). Diet and Immune Function. Nutrients, 11(8), 1933.
 Richardson, A. S., Arsenault, J. E., Cates, S. C., & Muth, M. K. (2015). Perceived stress, unhealthy eating behaviours, and severe obesity in low-income women. Nutrition Journal, 14, 122.
 Gibson, A., Edgar, J. D., Neville, C. E., Gilchrist, S. E., McKinley, M. C., Patterson, C. C., … Woodside, J. V. (2012). Effect of fruit and vegetable consumption on immune function in older people: a randomized controlled trial. The American Journal of Clinical Nutrition, 96(6), 1429–1436.
 Ibs, K.-H., & Rink, L. (2003). Zinc-Altered Immune function. The Journal of Nutrition, 133(5), 1452S–1456S.
 Cruzat, V., Macedo Rogero, M., Noel Keane, K., Curi, R., & Newsholme, P. (2018). Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation. Nutrients, 10(11), 1564.
 Hoffmann, P. R., & Berry, M. J. (2008). The influence of selenium on immune responses. Molecular nutrition & food research, 52(11), 1273–1280.
 Chirumbolo, S., Bjørklund, G., Sboarina, A., & Vella, A. (2017). The Role of Vitamin D in the Immune System as a Pro-survival Molecule. Clinical Therapeutics, 39(5), 894–916.
 Aranow C. (2011) Vitamin D and the Immune System. Journal of Investigative Medicine 2011;59:881-886.
 Sellami, M., Gasmi, M., Denham, J., Hayes, L. D., Stratton, D., Padulo, J., & Bragazzi, N. (2018). Effects of Acute and Chronic Exercise on Immunological Parameters in the Elderly Aged: Can Physical Activity Counteract the Effects of Aging?. Frontiers in immunology, 9, 2187. https://doi.org/10.3389/fimmu.2018.02187
 Nieman, D. C., & Wentz, L. M. (2018). The compelling link between physical activity and the body’s defence system. Journal of Sport and Health Science. doi:10.1016/j.jshs.2018.09.009
 J. Qin, R. Li, J. Raes, M. Arumugam, K.S. Burgdorf, C. Manichanh, T. Nielsen, N. Pons, F. Levenez, T. Yamada, D.R. Mende, J. Li, J. Xu, S. Li, D. Li, J. Cao, B. Wang, H. Liang, H. Zheng, Y. Xie, J. Tap, P. Lepage, M. Bertalan, J.-M. Batto, T. Hansen, D. Le Paslier, A. Linneberg, H.B. Nielsen, E. Pelletier, P. Renault, T. Sicheritz-Ponten, K. Turner, H. Zhu, C. Yu, S. Li, M. Jian, Y. Zhou, Y. Li, X. Zhang, S. Li, N. Qin, H. Yang, J. Wang, S. Brunak, J. Doré, F. Guarner, K. Kristiansen, O. Pedersen, J. Parkhill, J. Weissenbach, MetaHIT Consortium, P. Bork, S.D. Ehrlich, J. Wang, A human gut microbial gene catalogue established by metagenomic sequencing. Nature 464, 59–65 (2010). https://doi.org/10.1038/nature08821
 Thaiss CA, Zmora N, Levy M, Elinav E. The microbiome and innate immunity. Nature. 2016 Jul 7;535(7610):65-74. doi: 10.1038/nature18847. Review. PubMed PMID: 27383981.
 Lazar, V., Ditu, L.-M., Pircalabioru, G. G., Gheorghe, I., Curutiu, C., Holban, A. M., … Chifiriuc, M. C. (2018). Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer. Frontiers in Immunology, 9. doi:10.3389/fimmu.2018.01830
 Greenwood, B. (2014). The contribution of vaccination to global health: past, present and future. Philosophical Transactions of the Royal Society B: Biological Sciences, 369(1645), 20130433–20130433. doi:10.1098/rstb.2013.0433
 WHO (2020). Immunization: Vaccines and Diseases. World Health Organisation [online] available from https://www.who.int/immunization/diseases/en/
 Jacobson, R. M., St. Sauver, J. L., Griffin, J. M., MacLaughlin, K. L., & Finney Rutten, L. J. (2020). How health care providers should address vaccine hesitancy in the clinical setting: Evidence for presumptive language in making a strong recommendation. Human Vaccines & Immunotherapeutics, 1–5. doi:10.1080/21645515.2020.1735226
 Smith, D. A., & Germolec, D. R. (1999). Introduction to immunology and autoimmunity. Environmental health perspectives, 107 Suppl 5(Suppl 5), 661–665. https://doi.org/10.1289/ehp.99107s5661
 John Hopkins Medicine. (2020) Disorders of the Immune System. [online] Available at https://www.hopkinsmedicine.org/health/conditions-and-diseases/disorders-of-the-immune-system
 FUENTES, E., FUENTES, M., ALARCÓN, M., & PALOMO, I. (2017). Immune System Dysfunction in the Elderly. Anais Da Academia Brasileira de Ciências, 89(1), 285–299. doi:10.1590/0001-3765201720160487
 Montecino-Rodriguez, E., Berent-Maoz, B., & Dorshkind, K. (2013). Causes, consequences, and reversal of immune system ageing. The Journal of clinical investigation, 123(3), 958–965. https://doi.org/10.1172/JCI64096
 Gorina, Y., Hoyert, D., Lentzner, H., Goulding, M. (2005) Trends in Causes of Death among Older Persons in the United States. US Department of Health and Human Services: Center for Disease Control. [online] Available at https://www.cdc.gov/nchs/data/ahcd/agingtrends/06olderpersons.pdf
 Hamer, D. H., Sempértegui, F., Estrella, B., Tucker, K. L., Rodríguez, A., Egas, J., Dallal, G. E., Selhub, J., Griffiths, J. K., & Meydani, S. N. (2009). Micronutrient deficiencies are associated with impaired immune response and higher burden of respiratory infections in elderly Ecuadorians. The Journal of nutrition, 139(1), 113–119. https://doi.org/10.3945/jn.108.095091