How You Can Really Boost Your Immune System

As fears of the new coronavirus (Covid-19) spread, alternative medicine was quick to provide false reassurance in the form of misinformation and bogus remedies. A recurring theme in complementary and alternative medicine and a common mantra of those who make questionable health claims has long been “boosting the immune system.” So much so that boosting the immune system (or sometimes “supporting” the immune system) has become a red flag for quackery. It almost always indicates a misunderstanding of what the immune system is and how it works, and it fails to acknowledge that boosting the immune system could be counterproductive and might be exactly the wrong thing to do. They never really explain what it is they are hoping to boost. And they never explain why the immune system would need support or how exactly that support would work. It’s not like the aging breast that sags without support from a bra, and it’s not like a wobbly rose plant or vine that gravity would pull to the ground in a heap without the support of a trellis.

If you are a normal healthy person whose diet provides the essential nutrients, your immune system will be able to perform its functions quite well; and there is nothing you can do that will make it do a better job. As infectious disease specialist Mark Crislip wrote on the Science-Based Medicine blog, “The immune system is not a muscle, not a rocket, not a pump, not a balloon, nor anything else that can be inflated, expanded, or launched into the stratosphere by adding more power.”

You can indeed boost your immune system. I’ll explain later how you can do that, and it has nothing to do with all the vague, nonsensical, ignorant claims out there. But first, some background information is in order.

The immune system is a mind-bogglingly complex web of interconnected biological structures and processes. Working together, those components protect the organism from disease. There are actually two immune systems: innate and adaptive, both of which must distinguish between the body’s own cells and foreign invaders. And there’s also passive immunity, as provided to newborns by the colostrum in mother’s milk and as antibody-rich serum injections. Passive immunity is a way for those who aren’t actively producing their own antibodies to passively benefit from the antibodies of others. 

The innate immune system.

Barriers. The first level of defense is provided by physical barriers such as the skin, augmented by nonspecific chemical barriers. Mucus traps microbes in the respiratory tract and waves of cilia carry them away. Foreign invaders can be removed by coughing and sneezing or through sweat, tears, and urine. Antibacterial chemicals can be found in skin, saliva, tears, breast milk, and the vagina. The stomach kills ingested microbes with gastric acid. Beneficial intestinal bacteria outcompete pathogenic species. Even semen counteracts microbes with defensins and zinc.

Pattern recognition cells include macrophages, dendritic cells, mast cells, histiocytes, Langerhans cells, and Kupffer cells. They have receptors that can distinguish between molecules that belong to the body and those that don’t. They initiate the process of Inflammation, which attracts white blood cells and other phagocytes (cells that ingest and destroy pathogens). The body produces proteins called cytokines that mediate the inflammatory process with TNF, HMGB1, IL-1, and interferons. The complement system is activated to augment the inflammatory response. It consists of over 30 small proteins and protein fragments that work together in a cascade reaction. Another cascade reaction is the lectin pathway. And then there are at least ten toll-like receptors (TLRs) as well as inflammasomes and cytosomes. Not to speak of innate lymphoid cells such as natural killer (NK) cells. 

I’ve already lost count, and this is just the innate system. You can begin to see just how complicated the immune system is, and why a simple intervention is not likely to be effective. But wait, there’s more! Much more.

The adaptive immune system. 

The innate system is common to all organisms, but the adaptive immune system is a later development in evolutionary history, appearing in vertebrates to allow the body to “remember” and respond to specific pathogens that it has encountered before. Vaccination depends on this memory. Antigens are recognized by a special type of white blood cell, lymphocytes. They carry receptor molecules that attach to small fragments of a pathogen (antigens) and process them in association with major histocompatibility molecules that recognize “self.” Lymphocytes are divided into two types: B cells and T cells. T cells are further subdivided into killer T cells, helper T cells, and regulatory T cells. Activated T cells produce chemicals (cytotoxins) that kill foreign cells. Oh, and there are also gamma delta T cells with different receptors.

B cells present antigens and secrete antibodies. Their activation is enhanced by a series of chemicals. There are several types of B cell: plasmablasts, plasma cells, memory B cells, lymphoplasmacytoid cells, B2 cells, B-1 cells, and regulatory B cells. Antibodies are made up of two heavy chains and two light chains, with a variable region specific to an antigen. There are five major types of antibody: IgG, IgA, IgM, IgE, and IgD, with further subdivisions of some types. Millions of antibody molecules can be produced in a very short time.

Are you overwhelmed yet? Confused? As you can see, the immune system is insanely complicated. I’ve already listed the main components that make up the immune system, and there are more that I didn’t mention; my list is not exhaustive. Research may show that an intervention can increase the amounts of one or more of these components, but no research has ever shown that such interventions result in a clinically significant outcome like fewer infections. When a system is so complex, it’s foolhardy to tweak a single thread in the web, assuming you could actually do that. There’s a good chance it will have no significant effects on overall functioning or will have unanticipated effects that do more harm than good.

Immune disorders

The immune response can be deficient or excessive. Immune deficiency can be due to severe malnutrition or to genetic disorders such as severe combined immunodeficiency (SCID), as well as to HIV/AIDS infections or to immunosuppressive drugs. On the other end of the scale, excessive immune responses can result in:

  • Autoimmune disorders that attack the body’s own cells, such as rheumatoid arthritis (RA) and type 1 diabetes.
  • Allergies and hypersensitivity disorders (ranging from the runny nose and sneezing of hay fever to the potentially fatal anaphylactic reactions that can follow bee stings).
  • Inflammatory diseases (celiac disease, inflammatory bowel disease, asthma, transplant rejection and much more).
  • Cancers related to chronic infections and inflammation, such as liver cancers caused by hepatitis B and cervical cancers caused by human papillomavirus (HPV) infections.

Inflammation is both good and bad

When you cough with pneumonia or sneeze with a cold or experience pain with a boil or run a fever, it’s not the microbe itself that causes those symptoms, it’s your body’s own reaction, its efforts to deal with the bug. 

We need inflammation; it initiates the healing process and leads to recovery from diseases and injuries. But it also causes a lot of harm. Inflammation has been linked to atherosclerosis, blood clots, pulmonary embolus, heart attacks, strokes, and a host of other problems. As Mark Crislip pointed out, “if some product is really boosting your immune system, it is really activating your inflammatory response.” And that could be a very bad thing. Boosting your immune system could kill you. 

Fake claims abound

Some of the claims are for practices that they say will boost the immune system; but they will not. They are things like exercise, a good diet, and adequate sleep, which are good general advice for keeping the whole body healthy; but they have nothing specific to offer the immune system. If the immune system is already functioning adequately, they won’t make it work any better. All alternative health practitioners claim that their treatments will improve immune function. Chiropractors claim that adjusting the spine will do the job. Acupuncturists imagine they can accomplish it by sticking needles in nonexistent acupoints to somehow facilitate the flow of your equally nonexistent qi. Homeopaths have much to offer. Their top three “immunotherapy” remedies are allium cepa, gelsemium, and oscillococcinum. Oscillococcinum is a joke. It was the illusion of one man. It never existed in the first place, and even if it did, it would have been diluted out of existence in the preparation of the remedy.

One ad for a natural immunity product says “Prevent flu virus from attacking your system with a stronger immune system.” They are selling sachets for a plant-based natural drink mix with specially curated blends of these ingredients to boost immunity (to supposedly stimulate inflammation): Baobab, Orange, Turmeric, and Cami Camu. And these ingredients to fight inflammation: turmeric and holy basil. So what are they trying to do, promote or suppress inflammation? There’s no evidence that their product can do either.

Dr. Seeds is selling turmeric powder with the claim that it boosts the immune system. Where’s the evidence? A search for turmeric studies on PubMed indicates that the “evidence” is turmeric’s ability to modulate inflammatory signaling pathways[i] in preclinical studies and animal models.[ii] There are no significant studies of outcomes in humans. One review mentions the inflammatory signaling molecules NF-κB, JAKs/STATs, MAPKs, β-catenin, and Notch-1. These are all pathways I didn’t even mention in my explanation of the immune system: more complications and evidence of the incredible complexity of the immune response. There’s no clinical evidence that these components are important for human health.

Another advertised immune booster is colloidal silver “to support you through the cold and flu season.” It not only doesn’t work, it turns your skin permanently blue.[iii]
There are a multitude of products advertised to boost the immune system: oil of oregano, probiotics, echinacea, black elderberry… The list goes on; the evidence is nonexistent.

The term “boosting the immune system” is meaningless to anyone who really understands the immune system. It is only useful to help marketers deceive customers. The principle of “buyer beware” applies.

A reality-based immune booster

There is one way that you can actually boost your immune system. In a word, vaccines. They teach your immune system to recognize and fight off specific diseases. They do not cause generalized inflammation. They simply add more weapons to the adaptive immune system’s arsenal. They train it to produce large numbers of antibodies if you encounter that specific infective organism again. Multiple vaccines don’t overwhelm the body’s immune system; they just exercise it, giving it more opportunities to carry out its normal functions. 

Bottom line: vaccination works. Other ways of “boosting the immune system” don’t.


[i] https://www.ncbi.nlm.nih.gov/pubmed/31140036

[ii] https://link.springer.com/article/10.1007/s10787-019-00607-3

[iii] https://www.wired.com/story/does-colloidal-silver-work/

This article was originally published in Skeptical Inquirer.

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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