How Does Stress Affect the Immune System?

Functional medicine

In this article, Dr Matt Le Roux untangles the complicated web of stress and immune system and takes a deeper look at stress related illness. Can stress kill? Is it that bad? We’re often made aware of the dangers of stress but why is stress is bad for us and what does it really do to our bodies?

To understand the affects of stress and the immune system we must first understand our immune system.

What is the immune system?

Our immune systems are a complicated web of cells, tissues and organs that keep our bodies safe against viruses, bacteria, parasites, and more. They fight off diseases and infection to keep us healthy and can even build up immunity to ward off the return of unwanted illness. We become particularly susceptible to getting sick when our immune systems are compromised, or weak. This can be caused by a disease that attacks our immune system or commonly, by stress. Stress and the immune system are not friends. This is why you will often hear the term ‘stress related illness’ (Newman,T, 2018).

How does the immune system work?

Simply put, the immune system mounts a complex attack on foreign tissue. This foreign tissue includes any tissue that is not recognised as native to our body, in other words, tissue that is not ‘self’. It also includes our own dead or faulty cells. These cells are attacked and removed by the immune system to protect us against viruses, parasites, bacteria, stress related illness and more (Newman,T, 2018).

But how do stress and the immune system link together?

Stress and the immune system

When we are stressed, our bodies can produce the stress hormone, cortisol. The increase of cortisol has been linked to the decrease of lymphocytes. Lymphocytes (a type of white blood cell) are a critical part of our immune system that produce antibodies, destroy compromised cells and alert the other cells in our bodies that an immune response is required to action against an invader.

The negative effects of cortisol include suppressed immune system, serotonin decrease and decreased sensitivity to pain.

Stress related illness

A study has shown how long-term stress plays havoc with the immune system, raising the odds of catching a cold. Scientists in the U.S. questioned 176 men and women about difficult experiences they had been through in the past 12 months. Drops of the common cold virus were then dripped into their nose and scientists checked if they caught the germ. Those who had been under stress were twice as likely to develop a cold.

Stress and the immune system have a suggested direct relationship and a lower immune system makes us more susceptible to stress related illness (Reed; date unknown).

What foods can reduce cortisol?

Omega-3-rich Foods

⦁ Mackerel
⦁ Salmon
⦁ Sardines

B Vitamin-rich Foods

⦁ Leafy greens such as spinach, collard greens, turnip greens, and romaine lettuce
⦁ Liver and other organ meats
⦁ Pasture-raised beef.

Vitamin C-rich Foods

⦁ Citrus fruits like oranges, lemons, and grapefruit
⦁ Broccoli
⦁ Cauliflower

Probiotics and Prebiotics

⦁ Sauerkraut
⦁ Kimchi
⦁ Kefir
⦁ Seaweed

Magnesium-rich Foods

⦁ Dried apricots
⦁ Dark chocolate
⦁ Avocados

Olive Oils

For a more complete list of what foods can reduce cortisol, read this article of foods that reduce cortisol.

What are the symptoms of a weak immune system?

Stress and the immune system can create disastrous affects on our bodies such as stress related illness. The main symptom that a person with a lower immune system will experience is a disposition to infection. The infections may be more common than in other individuals and more difficult to treat or eradicate than in other individuals.

Infections that people with a weak immune system often get include:

⦁ Pneumonia
⦁ Meningitis
⦁ Bronchitis
⦁ Skin infections

These infections may recur with a high frequency. To find out if you have a weak immune system, you can visit your doctor and request a blood test for antibodies. The test will show whether your antibodies are in the normal range, and therefore whether or not your immune system has been weakened. A lower immune system cannot automatically be assigned to a stress and the immune system problem nor can a illness automatically be assigned to a stress related illness. Your doctor will help you address this (Fletcher; 2020).

I have a weak immune system, now what?

Whether stress and the immune system are to blame or whether you have a stress related illness may be unseen, however, there are some steps you can take to help you stay healthy with a lower immune system (Fletcher; 2020).

Be mindful of your mood

If you live a particularly high stress lifestyle this should be your go-to. Practise calming exercises like yoga or meditation. Plan your days in advance to ensure smooth sailing through out the day. Spend at least a small amount of time outdoors every day and be sure to surround yourself with supportive loved ones. Stress and the immune system are vital to your health when dealing with a lowered immune system (Fletcher; 2020).

Here’s an interesting thing to think about: If have a look at the primal physiology of humans, we’re built to experience stress when, for example, a sabre tooth tiger jumps out at us, or our lives are in danger. The modern stressors are much more frequent than those of our ancestors. From work stress to the car that jumps out in front of you in traffic. We’re experiencing stress at a much higher rate than ever before and it is negatively effecting our immune systems. It is therefore important that we take measures to manage and reduce stress. (Greenfield; date unknown)

⦁ Getting enough light
Not only does sunlight aid in establishing your circadian rhythm, which in turn helps you sleep better, but it also produces the happy hormone – serotonin. Serotonin is known to decrease stress levels and help us relax. Less stress means a healthier immune system. (Greenfield; date unknown)

⦁ Practise Yoga or meditation
Yoga and meditation are excellent methods for reducing stress. How often do you really spend stress-free? Yoga and meditation offer you an opportunity to focus all your energy on being present in the moment and a break away from stress. (Greenfield; date unknown)

Get enough sleep

Lack of sleep and the immune system has similar affects on our body as do stress and the immune system. Not enough sleep can disrupt the production of leukocytes (white blood cells) and leave us struggling to maintain a healthy and strong immune system. This has a compound affect when you consider that people who are stressed often have difficulty sleeping (Fletcher; 2020).

Eat a healthy diet

Stress and the immune system, or stress related illness, may also be addressed with a healthy diet. For people with a weak immune system, doctors generally recommend a diet that is rich in vegetables and fruit, which will provide plenty of nutrients.

“If a person is very immunocompromised, for example, because they are undergoing cancer treatment, a doctor may recommend that they take extra steps to avoid foodborne illnesses” (Fletcher; 2020).

These may include:

⦁ Washing all fruits and vegetables before peeling them
⦁ Avoiding undercooked meats, fish, and eggs
⦁ Refrigerating food promptly
⦁ Choosing pasteurized juices and dairy products over unpasteurized products

Exercise regularly

Another appropriate response to stress and the immune system, or stress related illness is regular exercise. Exercise will strengthen the body, the immune system and release endorphins – which reduce stress levels.
A word of caution to those with a highly compromised immune system: do not push yourself too hard as this can further weaken your immune system (Fletcher; 2020).

People with a weak immune system may wish to avoid exercising:

⦁ At too high an intensity
⦁ Too frequently
⦁ For extended periods without stopping to rest

However, regular, low intensity exercise is likely to be beneficial.

Consider taking supplements

Vitamin supplements can assist in your battle against stress and the immune system, or stress related illness. Some vitamins and minerals affect the immune system. For example, a person who has a vitamin C deficiency can have weakened immunity.

Other vitamins and minerals that can affect immune function include:

⦁ Vitamin A
⦁ Vitamin D
⦁ Vitamin E
⦁ Iron
⦁ Folic acid
⦁ Zinc

While vitamin supplements may be beneficial in boosting your immune system, they are not likely to cure or prevent disease. It is best to get nutrients from food where possible, but if this proves challenging, supplements may help with immunity (Fletcher; 2020).

Dr Matt Le Roux works with a variety of concerns, ranging from acute, chronic pain and complex injuries to nutritional, lifestyle, and performance enhancements. He is specialised in Sports Chiropractic and therefore can help you address concerns you may have surrounding stress and the immune system or stress related illness. To get in touch, visit

⦁ Newman, T; 2018. How the immune system works.
⦁ Reed, G; date unknown. Stress and the immune system.
⦁ Fletcher; 2020. How to stay healthy with a weak immune system.
⦁ Greenfield; date unknown. Why We’re All Chronically Stressed (And How You Can Combat Stress With Food And Supplementation).
⦁ Greenfield; date unknown. The 7 Best Stress-Fighting Weapons That Will Make Your Mind-Body Connection 100% Bulletproof.

Dr. Matt le Roux is a man of many talents: chiropractor, sports scientist and functional medicine practitioner. His science-based approach motivates him to explore the synergy between health and performance that changes the way you move, live, train, think, and eat.

Dr Matt le Roux

Chiropractor, Functional medicine practitioner

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