How Stress Affects the Immune System

The connection between stress and the immune system often goes unrecognized in conventional medicine. Stress is often thought of as something that occurs emotionally. While this is true, there are many other sources of stress on the body. Uncovering hidden sources of stress and restoring balance is a large part of the work of functional nutrition, especially when it comes to helping our clients solve digestive problems.

Before we dive too deep into the stress and immune system connection, we’re first going to review the basic principles of stress and how it affects the body.

• Acute versus Chronic Stress
• Stress and Inflammation
• Common Causes of Stress
• The Stress and Immune System Connection
  • Dietary Tips to Reduce Stress
  • Lifestyle Tips to Reduce Stress
• References

Acute Stress versus Chronic Stress

Acute Stress

Acute stress is caused by short-term events or injuries that place extra work on the body.  The sympathetic nervous system kicks in releasing stress hormones like cortisol and adrenaline to help your body recover from an immediate stressor.

For example, you are walking through your house at night to get a glass of water and you stub your toe.  Your body will employ mechanisms to heal your injured toe that results in heat and redness to the area. This is an inflammatory response that is a natural part of the body’s healing process.

Chronic Stress

Chronic stress is a result of the body being under stress for a prolonged period of time. The body responds with an extended release of stress hormones.

When the body is under constant stress, the immune system becomes overworked and isn’t able to function at its highest capacity. Normally, the immune system is responsible for things like cleaning up damaged cells and protecting the body against harmful pathogens. However, when the immune system is busy dealing with chronic inflammation, its regular responsibilities begin to suffer.

Another way to think about acute and chronic stress is to picture the work of firefighters:

1. Acute stress: Let’s say firefighters get called to a house that has caught fire and then they work very hard for a short period of time to put that fire out. The firefighters put out the fire and then are able to return to the fire station where they can do maintenance on their equipment, clean their uniforms, rest, and recover.
2. Chronic stress: Now, picture a different scenario as those same firefighters are called to one fire right after another with no time to go back to the fire station. There is no time for recovery because they are constantly fighting fires. Eventually, their equipment starts to break down, their clothes need cleaning and they need rest.

Stress and Inflammation

Anyone experiencing chronic stress will start to experience inflammation as a result of an overworked immune system. Symptoms of inflammation vary from person to person but may include:

• Digestive issues
• Headaches
• Fatigue
• Anxiety
• Depression
• Frequent illness
• Fertility issues
• High blood pressure
• High cholesterol
• Unexplainable rashes
• Acne
• Thyroid disorders
• High blood sugar

Common causes of stress

Stress is usually associated with negative events. But what’s interesting about stress, is that not all stressors are negative, some are positive. Stressors are anything that’s extra work on you/your body.

• Running a marathon
• HIIT training*
• Pregnancy
• Job promotions
• Injury or infection
• Environmental toxicity*
• GI stress due to food sensitivities*
• Bacterial imbalance in the gut*
• Planning a wedding
• Job
• Relational
• Grieving
• Deadlines
• Extra responsibilities
• Financial

*Commonly overlooked or hidden causes of stress

The Stress and Immune System Connection

Chronic stress takes a toll on the immune system. There are several reasons why many of which {of course} are related to nutrition:

• When we are under stress, our body burns through nutrients like vitamin C and B vitamins that are critical for an optimally functioning immune system. Even more interesting…these nutrients can easily become depleted and nutrient deficiencies are another source of stress on the body!
• Stress affects the gut by sterilizing the good gut bacteria. This creates opportunities for potentially bad pathogens to take over in the gut causing dysbiosis. Since 70-80% of the immune system cells live in the gut, this creates an altered immune response. If dysbiosis results, you are set up for an additional source of stress on the body.
• Stress can make us more susceptible to food sensitivities. Food sensitivities are often the result of an overworked immune response. A calm and healthy immune system won’t over-respond to things that are not harmful.
• The stress response sends signals to the gut to either increase pumping which results in loose stools or slow down motility causing bloating and constipation. Both diarrhea and constipation make it difficult to absorb nutrients from our food, again resulting in nutrient deficiencies which further exacerbate the stress response.
• Stress suppresses white blood cell response, these are responsible for fighting pathogens.

Dietary tips to reduce stress

• Reduce the amount of raw vegetables you are consuming, these are more difficult to digest than cooked. If you have a super sensitive tummy, you might even consider cooking your fruits as well.
• Increase your intake of soups and smoothies, these are easier to digest.
• Skip foods with high amounts of anti-nutrients such as phytates and lectins like grains or beans. If you do grains or beans, consider soaked and sprouted versions to reduce the anti-nutrient content.
• Eat fewer refined foods. Refined foods have less of the nutrients that fuel the immune system like vitamin C, zinc, glutamine, and B vitamins. If you fill up on less nutritious refined foods, you are displacing more nutritious foods {like colorful fruits and vegetables} with immune boosting properties.
• Go lower carb. High carbohydrate foods (especially when eaten by themselves) can cause elevated blood sugar. Elevated blood sugar is a stressor on the body that weakens the immune response.
• Eat less sugar. Sugar is a double whammy! It not only raises blood sugar, weakening the immune response, but it also feeds the bad bacteria that can compromise the immune system cells living in your gut.
• Intermittent fasting can be a helpful tool to support the immune system.
  • Fasting induces autophagy, which is basically cleaning up the body on a cellular level.  During autophagy, old cells that are no longer useful, cells that aren’t helpful, and even that are threatening (think pre-cancerous) are removed or recycled.
  • While it sounds great, intermittent fasting is not for everyone. For some, intermittent fasting can actually act as a stressor. For example, if you are underweight, pregnant, or have a history of disordered eating you’re likely not a good candidate of intermittent fasting. Also, recommendations for intermittent fasting are different for men and women.

Lifestyle tips to reduce stress

• Aim for at least 7 hours of high-quality sleep per night. This means that you wake well rested and aren’t tossing and turning all night. Deep sleep is important so energy can be restored, cells, tissues and bones can repair and regenerate – all of which improve immune system function.
• Choose less intense activities for exercise. When we’re under a lot of stress, intense workouts become an added source of stress on the body. So it’s probably not the best time to train for a marathon or start an intense boot camp five days a week!
  • The exercises below are recommended to help reduce stress. Participating in these exercises can reduce stress hormone levels, initiate the relaxation response, reduce inflammation, and support the immune system:
    • Walking outside
    • Pilates
    • Barre
    • Swimming
    • Standing more if you have a sedentary job
    • Weight lifting

• Meditation and affirmation. There is evidence that meditating regularly boosts the immune system and elicits the relaxation response.
  • Consider coming up with affirmations that will calm your mind.  Creating “I am…” affirmations essentially tells your body how you want to feel.  I am at peace. I am calm.  I am relaxed.

• Music therapy has been used for years to reduce the negative impact of stress on the body and has been shown to improve immune system function. Music therapy includes listening to music as well as playing your own.
• Talk Therapy. Reach out to a counselor or therapist to talk through some of your concerns, fears and stressors.
• Schedule time for yourself. There are only 24 hours during the day and often we are filling so many of those hours that there is not enough rest time.
  • Try blocking space on your calendar to make time for yourself. If this seems impossible, you might need to explore delegating some of your tasks to others.  Or maybe you’re saying “yes” to too many things.  In a time when we are told to glorify being busy, we recommend finding space to add in stillness and silence instead of filling your calendar!

References:

1. ^Besedovsky L, Lange T, Haack M. The Sleep-Immune Crosstalk in Health and Disease. Physiol Rev. (2019)
2. ^Prather AA, et al. Behaviorally Assessed Sleep and Susceptibility to the Common Cold. Sleep. (2015)
3. Stress, depression, the immune system, and cancer. Reiche EM, Nunes SO, Morimoto HK. Lancet Oncol. 2004 Oct; 5(10):617-25.
4. Psychological stress and antibody response to immunization: a critical review of the human literature. Cohen S, Miller GE, Rabin BS. Psychosom Med. 2001 Jan-Feb; 63(1):7-18.
5. ^Myles IA. Fast food fever: reviewing the impacts of the Western diet on immunity. Nutr J. (2014)
6. ^Jafar N, Edriss H, Nugent K. The Effect of Short-Term Hyperglycemia on the Innate Immune System. Am J Med Sci. (2016)
7. Mattson MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease processes. Ageing Res Rev. (2016)
8. ^Longo VD, et al. Interventions to Slow Aging in Humans: Are We Ready?. Aging Cell. (2015)
9. Thoma MV, La Marca R, Brönnimann R, Finkel L, Ehlert U, Nater UM. The effect of music on the human stress response. PLoS One. 2013;8(8):e70156. Published 2013 Aug 5. doi:10.1371/journal.pone.0070156
10. Black DS, Slavich GM. Mindfulness meditation and the immune system: a systematic review of randomized controlled trials. Ann N Y Acad Sci. 2016;1373(1):13‐ doi:10.1111/nyas.12998