Organisation of the immune system
The complexity of the immune system is considered secondary only to that of the nervous system.1
The immune system is classified in two broad categories. The innate immune system (non-specific immune system) and adaptive immune system (specific or acquired immune system). However, the relationship between the innate and adaptive immunity is far more complex, integrated and interdependent than it is described in most anatomy and physiology texts.
The microbiological, chemical and physical barriers are included in innate immunity; however, the main mediators of immune system that deliver instant defence include cytokines, acute phase proteins, macrophages, monocytes, complement, and neutrophils.2
In addition to being essential for adaptive immunity, the innate system is responsible for the early killing and clearance of infectious pathogens and the resolution of the inflammatory response. The most important means by which the immune system communicates internally and externally is through the use of cytokines. Cytokines play a crucial role in the selection, initiation and modulation of an appropriate immune response.1
The adaptive immunity is described as the second line of defence after a macrophage-mediated presentation of antigens to B lymphocytes, with the help of T lymphocytes. B cells then mediate the humeral immunity by producing high affinity antibodies and established immunological memory. T lymphocytes can mediate cellular immunity after activation by cytokines released from helper T cells.3
Adaptive immunity is acquired by generating antigen specific B and T lymphocytes through a gene rearrangement process. The exposure of the body to an antigen triggers an adaptive immune response that may develop within weeks but may last through the whole life. This is referred to as active immunity. The active immunity may either be acquired or natural.2
Disorders of the immune system
The immune system can give rise to several disorders when it is weakened or overactive.
|Immune system status||Attributable pathologies|
• Prone to opportunistic infectious diseases
• Chronic inflammation and autoimmunity
An underactive immune system increases the risk of opportunistic infection and uncontrolled neoplastic tissue growth, while an overactivated immune system leads to inflammation, allergy and autoimmunity.1
Inflammation and the immune system are intimately connected. Inflammation is involved in the development of several chronic diseases such as arteriosclerosis, diabetes, neurodegenerative diseases and cancer. Immune dysfunction is also associated with conditions such as chronic pain, anxiety, and depression.1
Haddad et al. ask if the immune system is a good target to select in the fight to prevent chronic disease. In targeting the immune system to prevent chronic diseases they remind us that the immune system carries out its important defensive function in intimate and coordinated interaction with the nervous system and endocrine systems. Therefore, they are concerned that targeting the immune system may be too reductionist an approach, particularly when dealing with complex pathologies such as cancer.1
Ortuño-Sahagún et al. state the term immunomodulation was originally used in reference to the response to a vaccination. The science underpinning immunomodulation traditionally involved the development of vaccines and the development of antigens to inducing immunogenicity and provoke a desired immune defence in the body.4
Researchers investigating immunomodulation are now examining how natural compounds, herbs, diet, traditional Chinese medicine (TCM), Ayurveda, psychological interventions and other treatments have an immunomodulatory activity.4
Immunomodulators are generally categorized as immunoadjuvants, immunostimulants, and immunosuppressants. Immunoadjuvants are specific immune stimulators which enhance the efficacy of vaccine.2
Agents that activate or induce the mediators or components of immune system are called immunostimulants. On the other hand, immunosuppressants are molecules that inhibit the immune system. These agents can be used in the treatment of hypersensitivity reactions and autoimmune diseases.2
Immunosuppressors are of interest in organ transplantation or in autoimmune disorders, where the immune system mistakenly activates an immune response against the body’s own tissues, leading to their destruction. On the other hand, immunostimulants boost the endogenous immune defences, allowing one to restore or maintain body homeostasis.3
Many medicinal plants have been traditionally used to boost the immune system. There are a number of ways in which they can act as immunomodulators; by stimulating both innate and adaptive humoral and cellular immunity, by interfering with proinflammatory pathways and by the modulation of the gut microbiome.3
One of the most well-known immunostimulant botanicals is echinacea (Echinacea purpurea (L.) Moench and E. angustifolia DC). It has an immunostimulant activity on both innate and adaptive immunity and also has antiviral, anti-inflammatory and antimicrobial activity.3
A review investigating the role of natural health products in modulating the immune system stated that while the results are encouraging there is a need to address the important issues of standardization in both product quality and research methodologies.1
Can we boost the immune system?
Wagner et al. are critical of the online increase in selling ‘immune boosting’ remedies or activities during COVID-19 which they are claim were misleading and scientifically inaccurate and they state that there is no evidence that any product or practice can boost the immune system to protect against COVID-19. They analysed popular immune-boosting posts on Instagram and claimed that nearly all were devoid of sound science and full of commercial content and many used scientific and medical rhetoric in their messaging.5
Timothy Caulfield expresses his frustration in what I consider a very biased article, Pseudoscience and COVID-19 – we’ve had enough already, published in Nature, regarding the explosion of misinformation on ways to ‘boost’ the immune system during the COVID pandemic.6 While I understand Claulfield’s frustration, I was disappointed that Timothy Caulfield refutes and dismisses all forms of natural therapies used to support the immune system.
He further enraged me when he suggests it is abhorrent and outrageous that universities and health-care institutions are conducting research into natural therapies. He claims this only propagates pseudoscience.
On one hand we are being asked to provide more scientific evidence to validate the role of natural remedies and on the other hand we have those who suggest that we should not support research into natural therapies. I’m sorry Timothy Caulfield, but your reasoning is hypocritical.
My biggest concern during the COVID-19 pandemic for complementary therapies, is the self-imposed censorship and the power that government health regulators had to crack down on health care providers such as chiropractors, naturopaths, herbalists and holistic healers. While I may not support many of the arguments of the anti-vaccination advocates, I do not believe this should lead to a crackdown on all complementary therapies that may be used for maintaining a healthy immune system.
Yes Tim, we do need good science, and please do not simply refer to it as pseudoscience simply because it is used to validate complementary therapies.
Schwarcz suggests it may be better to boost our knowledge about boosting our immune system. He is critical of advertising promoting an extensive range of natural products to boost the immune system such as mushroom extracts, probiotics, collagen supplements, exotic essential oils, bee propolis and a range of kefir-kombucha fermented products.7
He argues that while the notion of boosting the immune system to ward off nasty viruses sounds good, it is a scientifically meaningless claim.7
Once again, as I have often argued that having a knowledge of the functioning of the immune system does help us interpret such claims. Schwarcz does however acknowledge that poor diet, lack of exercise, impaired sleep, stress, and aging can diminish the immune response.7
He asks a very pertinent question when a claim is made about boosting the immune system – what exactly is being boosted?
White blood cells? Which type? Macrophages? Eosinophils? Killer T cells? Helper T cells? B cells? Lymphocytes? Chemical messengers? Which ones?
Interferons? Interleukins? Cytokines? Tumor Necrosis Factors? How about antibodies? IgG? IgA? IgM or IgE?7
Schwarcz claims the studies do not exist that show that certain natural substances can boost the immune system.7 However, the purpose of this blog is to prove that the studies do exist and the results of many of these studies support the immunomodulatory activity of many natural remedies.
Schwarcz does suggest there is one way we can boost the immune system and that is vaccination. This he explains is one way that has been proven to encourage the body to produce antibodies against invading organisms.7
Dr Suzanne Cassel, an immunologist at Cedars-Sinai, also claims the concept of boosting the immune system is inaccurate. She points out that the symptoms one experiences when one gets an infection are a sign that your body is fighting back against the infection or virus, triggering an immune response.8
Having a stronger immune system is a misconception and that having too much of an immune response may be just as bad as having a weak response.
Strategies often promoted to boost the immune system
While the concept of boosting the immunity is popular within holistic therapies some argue that the only evidence-based approach to boost the immune system is vaccination.
A study analysing the internet identified 37 different approaches to boosting the immune system. Some of the top ‘immune boosters’ being promoted by commercial websites included vitamins, minerals, antioxidants, probiotics and functional foods, as well as many other forms of complementary and alternative medicine (CAM) approaches.9
The authors of this study were concerned that CAM approaches to boost immunity were being considered as an effective alternative to vaccination. They also reported that those using naturopathy or herbal medicines are less likely to vaccinate against influenza.9
The same paper also reported the results of an Australian survey of over 9,000 individuals which found that those using naturopathy or herbal medicine were less likely to vaccinate against influenza.9
Macedo et al. recommend that public health websites, educational website, health portals, and professional organisations should specifically mention that vaccines ‘boost immunity’ against infectious disease.9
Many blogs promoting immune boosting strategies begin with attention grabbing headings such as - 8 science-backed ways to boost your immune system, according to experts. The 8 science backed approaches to boosting your immune system according Julia Blank, MD., family physician at Providence Saint John’s Health Center in Santa Monica, CA include:10
• Keeping your alcohol intake moderate
• Reducing stress levels
• Eating plenty of fruit and vegetables
• Load up on vitamin D
• Getting good sleep
• Washing your hands often
• Keeping up regular exercise
• Quit smoking if you have not done so already
Others have suggested that there is no magical immune system booster that will boost your immune system, but there are things you can do to protect your immune cells, which in turn lowers your susceptibility to infection such as:11
1. Eating the right foods
2. Getting the nutrients your immune system needs
3. Exercising more
4. Controlling stress levels
5. Getting enough sleep
6. Having a healthy, happy gut
7. Maintaining good personal hygiene
In most cases the ways to boost your immune system involve very simple practical strategies to maintain a healthy lifestyle and by maintaining a healthy lifestyle there is no doubt that our immune system will benefit.
The Heart Foundation also gets in on the act in promoting strategies in which we can boost our immune system. It was very interesting that the focus of the heart foundation article was that our immune system begins in the gut and that maintaining a healthy gut microbiome would help strengthen our immune system. While they recommend vitamin C and vitamin D, they state that if you are eating well and getting enough sunshine you are only flushing your money down the drain by taking supplements.12
The WebMD website also supports the notion that lifestyle interventions can boost the immune system. They report 6 key factors that will keep our immune system healthy. These include – getting enough sleep, exercising enough, making sure you have a healthy diet with more fruit and vegetables as well as eating a variety of mushrooms, reducing your level of stress, staying connected with friends and family, and maintain a sense of humor.13
On the other hand, Psychologist Melissa Burkley suggests some minor changes to your daily routine can help support your body’s immune system. Burkley recommends reducing stress, getting good quality sleep and regular exercising are suggested. Burley also recommends that we socialize more, focusing on the importance of social interaction. While social distancing and lockdowns have made this difficult. There is plenty of research indicating the impact of loneliness, which leads to more stress, which in turn leads to a weakened immune system.14
Burkley also mentions the importance of dialling down inflammation. In this case she explains how inflammation is a natural immune response; however, there are many factors that aggravate our inflammatory response such as sugar, alcohol, gluten, dairy, environmental toxins, processed meats and highly processed vegetable oils, just to name a few.14
Therefore, a healthy diet is going to be the best way to reduce chronic inflammation. Burkley suggests if you want a strong immune system, you need to remove foods that aggravate inflammation from your diet.14
• Check labels and avoid added sugars.
• Eat healthy fats (fish, olive oil, avocado oil, nuts, grass-fed beef) and avoid bad fats (vegetable oil, canola oil, palm oil, and corn oil).
• Adopt a plant-heavy, anti-inflammatory diet such as the Mediterranean diet.
• When it comes to the ‘dirty dozen’ fruits and vegetables, buy organic.
• Rice is high in arsenic. If you eat rice, she recommends eating Basmati rice as it has the lowest level of arsenic.
• Avoid eating fish high in mercury such as mackerel, tuna and swordfish.
Burkley also recommends laughter as the best medicine to boost our immune system.14
A 2001 study found that humor and mirthful laughter resulted in an increase in natural killer cell and immunoglobulin antibodies activity for up to 12 hours.15
Burkley also highlights the strong link between mood and immunity and states that people who regularly felt positive emotions were less likely to catch a cold than those who rarely felt positive emotions. She recommends singing our way to better health. I find this one interesting as singing was one activity that during the COVID-19 lockdowns was discouraged and even banned as it increased the risk on COVID-19 infection.16
Burkley also references a study that found that just listening to music did not have any impact on immunity.16
On the other hand, while Harvard Health decides to use an attention-grabbing heading – How to boost your immune system, they quickly explain while the idea of boosting your immune system sounds very enticing, the ability to do so is elusive. The article points out that the immune system is a complex system that requires balance and harmony and that there is still much researchers do not know about the intricacies and interconnectedness of the immune response.17
They state the need for more research that explores the effects of diet, exercise, age and psychological stress on the immune response.17
The article then promoted the usual good-health guidelines that will keep your immune system working properly such as not smoking, eating lots of fruit and vegetables, getting adequate sleep, drinking alcohol in moderation and minimizing stress. However it also adds one that many of the other websites did not list, and that is keeping up to date with your vaccines.17
The same article then also challenges the notion of ‘boosting’ the immune system and that it makes little sense scientifically. How do we know which part of the immune system to boost? There are so many cells that make up the immune system, which cells do we boost?17
An article in the Washington Post tells us to forget about ‘magic pills’ to boost the immune system and to instead focus on sleep, exercise, diet and reducing stress.18
The article cites Rene Leon, a clinical immunologist at Texas Regional Allergy and Asthma Center who states that while nutrition is definitely important to stay healthy and have a healthy immune system, there are no single foods that can bolster immunity. It should be more about eating a well-balanced diet with emphasis on whole foods rather than processed ones.18
It was also suggested that the best way to boost your immune system against COVID-19 is with one of the vaccines that are now available.18
Harvard health also promotes healthy lifestyle as a means to strengthen your immune system. The term they use is more restrained, when they state ‘following general good-health guidelines is the single best step you can take towards naturally keeping your immune system working properly’.17
They list - not smoking, exercising regularly, maintaining healthy body weight, drinking alcohol in moderation, obtaining adequate sleep, minimizing stress and keeping up with recommended vaccines as such strategies.17
The Harvard Health blog also acknowledges that as we age, our immune response is reduced which may lead to increased risk of infections and cancer. A reduced immune response has also been demonstrated by older people’s response to vaccines. However, while influenza vaccines have been shown to be less effective for people over the age of 65 compared to healthy children, vaccines have reduced the rates of sickness and death in older people when compared with no vaccination.17
Are vaccines immune boosters?
Jon Wardle, Professor of Public Health at Southern Cross University, reminds those of us who follow a natural health philosophy that vaccinations have more in common with natural health approaches than differences.19
A 2016 review by Wardle et al. 2016 found that there is no default position on immunization by CM practitioners or parents who use complementary medicine. The study suggested that opposition to vaccination was often more aligned to an individual’s personal beliefs than a default philosophical position related to natural medicine.20
Wardle reminds us that people often overlook that the adaptive immune response caused by vaccination is natural;
Vaccinations prepare the body’s immune system in the same way as natural exposure to infection does. It just does it in a safer, controlled way with a much larger dose.19
He argues that vaccines, once properly tested and assessed for safety and efficacy are a preventative strategy that supports and develops the body’s own healing systems to fight disease. Vaccinations also provide the opportunity to avoid aggressive treatment and management of infection and associated symptoms later on.19
1. Haddad PS et al. Natural health products, modulation of immune function and prevention of chronic diseases. eCAM 2005;2(4):513-520. doi: 10.1093/ecam/neh125
2. Jantan I et al. Plant-derived immunomodulators: an insight on their preclinical evaluation and clinical trials. Frontiers in Plant Science. 2015;6:655. doi: 10.3389/fpls.2015.00655
3. Di Sotto A et al. Plant-derived nutraceuticals and immune system modulation: an evidence-based overview. Vaccines. 2020;8:468. doi: 10.3390/vaccines8030468
4. Ortuno-Sahagun D et al. Natural immunomodulators 2018. Journal of Immunology Research. Journal of Immunology Research. 2019.
5. Wagner DN et al. “Immune boosting” in the time of COVID: selling immunity on Instagram. Allergy, Asthma & Clinical Immunology. 2020;16:76. doi: 10.1186/s13223-020-00474-6
6. Caulfield T. Pseudoscience and COVID-19 – we’ve had enough already. Downloaded on 25 April 2022 from https://www.nature.com/articles/d41586-020-01266-z
7. Schwarcz J. Boost your knowledge about boosting your immune system. Downloaded on 1 Feb 2022 from https://www.mcgill.ca/oss/article/critical-thinking-health-general-science/boost-your-knowledge-about-boosting-your-immune-system
8. Cedars-Sinai Staff, Can you really boost your immune system? Downloaded on 1 Feb 2022 from https://www.cedar-sinai.org/blog/boosting-your-immune-system.html
9. Macedo AC et al. Boosting the immune system, from science to myth: analysis the infosphere with google. Frontiers in Medicine. 2019;6:165. doi: 10.3389/fmed.2019.00165
10. Miller K. 8 science-backed ways to boost your immune system, according to experts. Downloaded on 1 Feb 2022 from https://www.prevention.com/health/a31386522/how-to-boost-immune-system/
11. How to boost your immune system. Downloaded on 1 Feb 2022 from https://www.circlehealthgroup.co.uk/health-matters/health-and-wellbeing/boost-your-immune-system
12. Hursthouse N. Boost your immune system to fight infection. Downloaded on 1 Feb 2022 from https://www.heartfoundation.org.nz/about-us/news/blogs/boost-your-immune-system-tofight-infection
13. 6 immune system busters & boosters. Downloaded on 1 Feb 2022 from https://www.webmed.com/cold-and-flu/cold-guide/10-immune-system-busters-boosters#1
14. Burkley M. 5 habits that strengthen your immune system against covid-19. Posted May 26 2020. Downloaded on 17 Feb 2020 from https://www.psychologytoday.com/sg/blog/the-social-thinker/202005/5-habits-strengthen-your-immune-system-against-covid-19
15. Berk LS et al. Modulation of neuroimmune parameters during the eustress of humour-associated mirthful laughter. Alternative Therapies in Health and Science. 2001;7(2):62-72.
16. Burkley M. 5 more immune-boosting habits to help fight off covid-19. Posted June 1, 2020. Downloaded on 17 Feb 2020 from https://www.psychologytoday.com/us/blog/the-social-thinker/202006/5-more-immune-boosting- habits-help-you-fight-covid-19
17. How to boost your immune system. Downloaded on 1 Feb 2022 from https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system
18. Aschwanden C. To boost immunity, forget ‘magic pills.’ Focus on sleep, exercise, diet and cutting stress. Downloaded on 1 Feb 2022 from https://www.washingtonpost.com/health/boosting-your-immune-system/2021/01/29/256fd52c-3fc4-11eb-8db8-395dedaaa036_story.html
19. Jon Wardle. Follow a natural health philosophy? Vaccination may have more in common with it than you think. downloaded on 18 April 2022 from https://www.scu.edu.au/engage/news/latest-news/2021/follow-a-natural-health-philosophy-vaccination-may-have-more-in-common-with-it-than-you-think.php
20. Wardle J. Complementary medicine and childhood immunization: a critical review. Vaccine. 2016;34(38):4484-4500. doi: 10.1016/j.vaccine.2016.07.026