Although you can’t “boost” your immune system to perform at superhuman levels, there are many factors that contribute both positively and negatively to a healthy functioning immune system.

By now most of us know how to try to avoid picking up viruses and other pathogens (big word for any organism that can cause disease) by sanitising, washing hands regularly with soap and hot water, keeping a safe distance from infected people etc. but do we know enough about how to prepare our immune systems to do their jobs if we do become infected?

Firstly, we are surrounded by pathogens all the time. Fighting them off and generally protecting you from harm is what your immune system exists for and, all being well, it does a pretty miraculous job. When the immune system fails, however, it can have a variety of adverse consequences, including reduced ability to fight infections.

The immune system, as with all body systems, does not act in isolation, but as part of a highly integrated system of cellular responses which can be both positively and negatively affected by your diet, lifestyle, environment and mental state.

Although the inner workings of the immune and other interconnected systems are complex, there are some very simple measures that we all can take to make sure our immune systems can work as effectively as possible:

1. Sleep

Prioritising sleep is one of the most important things you can do in order to stay healthy. Lack of sleep negatively affects your immune system. Research shows that people who don’t get enough sleep (less than 6 hours) are more likely to get sick after being exposed to a virus and show slow recovery.

Have a set “bed time” and stick to it as much as possible. Consistency is key to regulating your body clock which will help you to fall and stay asleep. Devote the last 30 – 60 minutes before bed to winding down away from bright lights and electronic devices. Take a bath, read a book, meditate, journal or whatever it is that makes you feel calm and relaxed.

Wake around the same time every day and try to be exposed to light (natural if possible) for 30 minutes after waking.

2. Proper nutrition

Healthy immune cells need proper nourishment in order to do their job. Scientists have long recognised that malnourished people are more vulnerable to infections. About 80% of the immune system starts in the gut, so when it’s healthy, we are more healthy.

There’s no one magic vitamin or herb you can pop to prevent infections but there are a number of nutrients that support immune function. Low levels of specific nutrients, namely vitamins A, B6, B9, C, D and E, and vital minerals like copper, iron, selenium and zinc can lead to a less responsive immune system.

The best way to provide your body (and therefore immune system) with all of the nutrients it needs is to eat a variety of fresh, colourful fruit and vegetables, good quality protein from organic sources, and healthy fats such as olive oil, nuts, seeds and fatty fish. Limit processed, high sugar, high fat, fried and charred foods as much as possible.

3. Minimise alcohol  

Having a few glasses may seem like a good way to cope with the current lock down, however, scientists have long observed a negative association between alcohol consumption and the body’s ability to defend against infection due to weakened defences and increased inflammation.

One of the most significant ways in which alcohol impacts the immune system is by weakening the structure and integrity of the gut allowing pathogens to “leak” into your circulation. It also alters the numbers of microbiota (community of good and bad microbes that live in your intestinal tract) that aid in normal gut function and absorption of vital nutrients.

It’s okay to have an occasional drink but avoid drinking everyday, give your system a break!

4. Cut caffeine 

Caffeine can also negatively impact the immune system in an indirect way. Drinking caffeine blocks the absorption of specific nutrients like vitamin B6, calcium, iron, magnesium and zinc, some of which are needed for proper immune function.

Caffeine also triggers the release of cortisol, a stress hormone, and can increase stress and anxiety and disrupt sleep. See points 1. and 8. for why this is bad and how it impacts your immune system. A perfect example of the interconnectedness of our body systems with each other and our lifestyles.

5. Go outdoors

Aside from the benefits of getting some fresh air and exercise outdoors, exposing your skin to direct sunlight for around 20 minutes per day (without getting burnt) is essential for boosting your vitamin D levels. Vitamin D is essential for proper immune function, healthy bones and mood boosting. The body can’t make vitamin D and very few foods contain it so the best (and most fun) way of keeping levels up is to spend time outdoors in possible. Supplements are also available for those who for one reason or another can’t get sufficient exposure to sunlight.

6. Exercise

Exercise has the capacity to protect and even enhance the immune system. Excessive exercise (at levels of endurance athletes) has a negative effect on the immune system but more modest exercise such as brisk walking, swimming, cycling, yoga, Pilates, Tai Chi and such, can enhance the immune system.

A weekly program of 20-30 minutes for 5 days of the week is ideal training for the immune response. Exercise also has the added benefit of being a mood enhancer.

Exercise (besides gentle walking) is not advised if you are sick.

7. Don’t smoke!

If you smoke, do everything you can to quit. Smoking is the single most avoidable negative influence on immune health. Along with exposure to harmful chemicals, smoking is associated with increased incidence of brain, lung, heart and infectious diseases and increased inflammation.

The chemicals in cigarette smoke cause damage to the body and use up vital anti-oxidant nutrients such as vitamins A, C, E, selenium and zinc – the exact same nutrients needed by your immune system to function properly.

One of the two main things known about the COVID-19 is that it enters human cells via the ACE2 receptor which is more active in smokers. This is thought to be one of the reasons that men seem to be more affected since in Iran, China, Italy and South Korea, female smoking rates are much lower than males.

The second factor is that in the later stages of the disease the lungs are affected. Smokers have a higher likelihood of being vulnerable to respiratory viruses.

8. Stress

Although it is difficult to entirely avoid stress in this day and age, being out of harmony with our inner selves has consequences for the immune system. The outbreak of the coronavirus has many people feeling stressed. Scientific study over the past 20 – 25 years has clearly demonstrated that the central nervous system (think stress), the endocrine (think hormones) and the immune system interact in complex ways.

In a nutshell, stress (which can be short-term like taking an exam, or chronic like divorce, mood disorders, bereavement, negative mindset etc.) negatively affects the immune system and increases risk of infections and slows down recovery.

There are many ways to deal with stress depending on the cause. Some techniques for stress management include counselling, exercise (particularly outdoors or mind-body practises, taking up a hobby, meditation, mindfulness and regular massage.

References: 

  1. Brake, SJ et al (2020) Journal of Clinical Medicine: Smoking Upregulates Angiotensin-Converting Enzyme-2 Receptor: A potential adhesion site for novel coronavirus SARS-CoV-2 (Covid-19)
  2. Calabrese, LH, R.J. Frasenmyer Chair of Clinical Immunology at Cleveland Clinic (2017): Maintaining a Healthy Immune System: What you can do to help
  3. Harvard Medical School (2014): How to Boost Your Immune System
  4. Preston, AM (1991) Prog Food Nutri Sci: Cigarette smoking – nutritional implications
  5. Qui, F et al (2017) Oncotarget: Impacts of cigarette smoking on immune responsiveness: Up and down or upside down?
  6. Sarkar et al (2015) Alcohol Res: Alcohol and the Immune System
  7. Wolde, T (2014) Effects of caffein on health and nutrition: A Review
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