The concept of “boosting” your immune system has long been a popular one, but what’s the science behind it, and is there anything you can do to give your immune system a helping hand?
The immune system at a glance
The purpose of the immune system is to protect our body against disease. This means not only defending it against invasion by bacteria, viruses, and parasites, but also playing a crucial role in wound healing, fighting off cancer, and maintaining a balanced inflammatory and anti-inflammatory environment - so it correctly recognizes you as you and doesn’t attack itself (a condition known as autoimmunity).
Your immune cells are the white blood cells in your body, also known as leukocytes. There are different types of specialized leukocytes. These can be grossly divided into two broad arms of the immune system- innate and adaptive.
The innate immune system is your body’s nonspecific and first line of defense, while the adaptive immune system takes longer to work and targets specific foreign invaders, has a memory of previous invaders, and is made up of T cells and antibody-producing B cells.
So what are some of the things you can do to ensure these specialized cells are given their best chance to protect your body? Here are a few ways to take control.
Manage your stress
Short term stress, lasting minutes to hours, can actually be beneficial for the immune system, whereas chronic stress, lasting several hours per day for weeks or months, has a harmful effect.1
Chronic stress can mess with the immune system and worsen pro-inflammatory and autoimmune diseases, as well as suppress the immune system. Chronic stress can delay wound healing, impair the body’s response to vaccinations, and increase susceptibility to infections and cancer.1
Long-standing stress has even been shown to prematurely age T cells, making them lose their functionality at least a decade earlier compared to someone with low-stress.2
Top tip
In addition to lifestyle and psychosocial factors - activities such as meditation, yoga, being in nature, exercise/physical activity, music, art, craft, dance, fishing, and painting reduce bad stress and optimize good stress.1
Laugh often
Ever heard that laughter is the best medicine? Well, it might be just what the doctor ordered!
Studies on laughter have shown that it benefits individual organ systems as well as the body as a whole. It causes the brain to release feel-good endorphins, stimulates improved blood circulation, and eases muscle tension.
It also affects your stress response and in the long term releases neuropeptides that help fight stress and illness3. Laughter has even been shown to improve the immune systems of patients on chemotherapy for cancer.4
Exercise regularly (but not too much)
Exercise induces a physiological stress response and increases circulating concentrations of adrenaline, noradrenaline, and cortisol which, when done regularly but not excessively, has a positive effect on the immune system.
Physical activity can modulate cancer-related pathways and improve some biomarkers associated with a better prognosis. Moderate and regular physical activity reduces the risk of cancer occurring, progressing, and cancer-related death.1
On the other hand, intense, prolonged exercise or exercising under extreme environmental conditions may lead to chronic exposure to stress hormones that make people susceptible to the negative health effects of chronic stress.
Exercise-induced pain, exhaustion, or injury have also been shown to induce psychological stress.1
Top tip
There is no defined specific amount of exercise considered too much or too little that applies to every person, more research is needed here. But listening to your body and avoiding activities that are drastic changes from your norm is a good way to go.
Get enough sleep
Sleep and circadian rhythms are strong regulators of the immune process. Prolonged, disrupted sleep and the associated stress response causes both a persistent low-grade inflammation leading to increased risk of various diseases and at the same time an immunodeficiency characterized by increased susceptibility to infections.5
Those who don't get enough quality sleep are more likely to get sick after being exposed to a virus. They also recover more slowly when they do get sick. A good sleep after a vaccination has been shown to improve the formation of antibodies and immunologic memory, meaning, more effective protection against disease in the future.5
In addition, antibodies and the activity of T cells that fight infection are reduced when you don’t get enough sleep.5.6
Top tip
For most adults, 7 to 8 hours of quality sleep every night is considered optimal.
Fuel your microbiome
The genes coding for the trillions of microorganisms living in and on us are known as the microbiome. These microbes play a role not only in digestion but also in keeping our immune system in balance.
Top tip
Certain foods called prebiotics and probiotics, exercise, and avoiding unnecessary antibiotics can favor the growth of beneficial bacteria in your body.
Limit alcohol intake
Alcohol consumption alters both innate and adaptive immunity. In excess, it impairs the way cells of the innate immune system talk to each other and recruit other cells to help fight off infection. Chronic alcohol abuse leads to increased susceptibility to bacterial and viral infections, such as bacterial pneumonia, tuberculosis, and exacerbated disease in chronic viral infections like HIV and Hepatitis C.7
Not only does it decrease the number of certain T cells needed to fight infection, but it can also increase the type of antibodies that play a role in autoimmunity, thus favoring a pro-inflammatory environment that might exacerbate allergy and autoimmune disease. It also suppresses the body’s ability to perform at its best in response to vaccinations. 7
Studies have also shown that those with alcohol use disorder are often deficient in one or more essential nutrients that play an important role in immune balance and infection response. These include Vitamin A, C, D, E, folate, and thiamine (B1).7
Top tip
If you do drink, avoid binge drinking and stick to the government guidelines - no more than fourteen units per week for both men and women, divided across at least three days per week.
Get your vitamin D
Cells of the immune system called antigen-presenting cells, convert vitamin D to its active form, which is highly concentrated in lymphoid tissues where it can modulate the function of T and B cells.
Vitamin D is needed for many different physiologic processes and its deficit can result in problems including the reduced activity of immune system defenses marked by an increased risk of certain cancers, but also disrupted immune system regulation as seen in observational studies linking vitamin D deficit to many different autoimmune diseases.7
Top tip
Natural sources of Vitamin D include the sun, oily fish, red meat, liver, egg yolk, and fortified foods such as milk, but it’s difficult to get enough vitamin D from food sources and sun alone (especially in the darker months!). The NHS recommends everyone to consider taking 10mcg (equivalent to 400 IU) of vitamin D each day.
References
- Dhabhar, FS. Effects of stress on immune function: the good, the bad, and the beautiful. Immunol Res. 2014; 58:193-210.
- Epel E, Blackburn EH, Lin J, Dhabhar FS, Adler NE, Morrow JD, Cawthon RM. Accelerated telomere shortening in response to life stress. PNAS. 2004;101:17312–5.
- Chang C, et al. Psychological, immunological and physiological effects of a Laughing Qigong Program (LQP) on adolescents. Complementary Therapies in Medicine. 2013;21:660.
- Sakai Y, Takayanagi K, Ohno M, Inose R, Fujiwara H. A trial of improvement of immunity in cancer patients by laughter therapy. Jpn Hosp. 2013;(32):53-59.
- Besedovsky L, Lange T, Born J. Sleep and immune function. Pflugers Arch. 2012 Jan;463(1):121-37. doi: 10.1007/s00424-011-1044-0. Epub 2011 Nov 10. PMID: 22071480; PMCID: PMC3256323.
- Dimitrov S, Lange T, Gouttefangeas C, et al. Gαs-coupled receptor signaling and sleep regulate integrin activation of human antigen-specific T cells. J Exp Med. 2019;216(3):517-526.
- Barr T, Helms C, Grant K, Messaoudi I. Opposing effects of alcohol on the immune system. Prog Neuropsychopharmacol Biol Psychiatry. 2016 Feb 4;65:242-51. doi: 10.1016/j.pnpbp.2015.09.001. Epub 2015 Sep 14.
