Written by Benjamin Semmens, Registered Nutritionist (BHSc)

Your immune system is a complex network of cells, organs and proteins that help your body fight off foreign invaders such as bacteria, viruses and parasites that cause infection.

Your immune system is incredibly clever as it remembers and recognises every germ (bacteria or virus) that it has fought in the past to be able to swiftly act on and destroy these nasty buggers if they enter the body again.

There is a common misconception that you need to go on radical diets, buy a bunch of supplements and bio-hack in every way possible to keep your immune system healthy.

However, there are simple diet and lifestyle changes that you can make to improve your immune response to help fight off these foreign invaders!

In this blog you’ll learn some simple tips to keep your immune system healthy and how to easily implement these changes into your busy life!

1. Get a good night’s rest 

When it comes to keeping your immune system healthy there is no better place to start than by getting a good night’s rest.

Studies have indicated that sleep deprivation can affect the maintenance of our immune cells, while also increasing inflammatory chemicals that are a risk factor for chronic conditions such as heart disease, asthma and certain cancers (1).

Getting adequate sleep can help to naturally strengthen your immune system. This also helps to explain why you need more rest when you are sick to help your body recover (2).

Furthermore, a 2015 study of 164 healthy adults found that those who slept fewer than 6 hours each night were at a greater risk or catching a cold than those who slept 6 or more hours a night (3).

Adults are recommended to get 7 – 9 hours of sleep each , teenagers around 8-10 hours, with younger children and infants needing up to 14 hours! (4)

A simple way to improve your sleep hygiene is by avoiding screen time at least an hour before bed. The reason why is that blue light is emitted from electronic devices such as your phone, TV or computer that disrupts your body’s natural sleep-wake cycle known as your circadian rhythm (5).

Other sleep hygiene tips include sleeping in a dark room, waking up and going to bed at the same time each night, regular exercise, and limiting caffeine in the afternoon.

2. Stress Management

Managing stress and anxiety is a step you can take to support your immune heath as chronic stress wreaks havoc on your immune system. 

When you’re stressed your body releases a stress hormone called cortisol that is part of your flight or fight response that helps us deal with dangerous situations.  

Cortisol has an anti-inflammatory effect short-term that can help us to deal with stressors. However, chronic stress can lead to excessive cortisol production that blocks your immune system’s ability to effectively fight infection.

That’s why you might have noticed you get sick after a long stressful period when your nervous system starts to calm down (eg. after exams, or when you go on holiday!)

Studies have demonstrated that chronic stress promotes inflammation and an imbalance in immune cell function (6, 7).

Stress management is also important for reducing cortisol that keeps us in heightened state that makes it harder to get a good night’s rest! (8)

Some simple tips to manage stress and anxiety are mindfulness techniques that include meditation, breath-work, yoga, exercise, journaling. If you feel that you need further support psychological help with a counsellor or therapist may be beneficial too.

3. Eat more plants!

There are a plethora of nutrients that are essential to support a healthy immune system that include vitamin A, C, E, D, zinc, selenium, iron, fibre, omega 3 fatty acids and protein (be sure to read last week’s blog 11 Nutrients you need to Boost your Immune System! to learn more) 

One of the easiest ways to get these nutrients is by consuming a plant-based diet. A plant-based diet is typically rich in fruits, vegetables, nut, seeds, and legumes that are full of the nutrients needed to support your immune system.

Plant-based diets are also rich in antioxidants that help to reduce inflammation by fighting free radicals in the body.

Free radicals are unstable atoms that can damage cells causing inflammation (aka oxidative stress) that is associated with chronic health conditions such as heart disease, Alzheimer’s disease and certain cancers (9).

4. Cut back on sugar

Studies have shown that excessive sugar in the diet can suppress your immune system.

Added sugars have been found to raise blood sugar and increase the production of inflammatory chemicals that negatively effect your immune function (10).

Furthermore, high blood sugar levels have shown to alter our immune response by reducing our gut barrier function leading to an imbalance in of gut bacteria (dysbiosis) that increases your risk of infection (11, 12).

Avoid refined sugars as much as possible that are found in soda, sugary snacks, processed foods, baked goods and alcohol.

5. Maintain a healthy gut 

Another simple way to support immune system by maintaining a heathy gut!

A healthy gut microbiome (gut bacteria) can also strengthen your immune system by helping to keep harmful germs from entering your body through the digestive tract. This is important as approximately 70% of your immune system is found in the gut! (13)

You can support a healthy gut by eating more fibre. Fibre is the indigestible parts of plant foods, such as vegetables, fruits, grains, beans, seeds and legumes.

Fibre is important as it helps to keep our digestive system healthy by feeding our gut bacteria (gut microbiome). When you eat fibre our gut bacteria produce short chain fatty acids (SCFA) that exert an anti-inflammatory effect that supports the immune system (14, 15).   

Aim to eat 30-40g of fibre/day to keep your gut and immune system healthy. You can help to do this by adding hemp seeds to your diet that contain approximately 7g of fibre per 100g (16).

6. Exercise moderately

Regular exercise has many benefits such as improving heart health, weight management, reduces your risk of diabetes and some cancers, stronger bones and muscles, boosts your mood and can help to keep the immune system healthy (17). 

Moderate exercise has shown to improve immune defence activity and has an anti-inflammatory effect in the body through multiple mechanisms. Regular exercise also improves immune regulation, delaying the onset of age-related dysfunction (18).

In fact, a 2019 scientific review in the Journal of Sport and Health Science found that exercise can improve immune responses, lower the risk of illness, and reduce inflammation.

Some examples of moderate exercise include brisk walking, bicycling, jogging, swimming, cleaning the house or even mowing the lawn! Most adults should aim for minimum 2.5 – 5 hours of moderate intensity exercise a week. 

7. Quit Smoking

Cigarette smoke contains more than 7,000 chemicals that can affect your health.

Smoking also affects your immune systems ability to fight off infection and disease by compromising the balance of the immune system and increases the risk of autoimmune disorders.

Furthermore, smoking can worsen conditions such as viral and bacterial infections (eg. pneumonia & influenza), rheumatoid arthritis, Crohn’s disease and cancers (19). 

There are lots of benefits to quitting smoking, that not only include improving your health and immune function but saving money too! To learn more about how to make a quit plan click here.

8. Go easy on the booze

While moderate amounts of alcohol consumption may have a protective effect on health, large amounts of drinking can suppress the function of the immune system and increase your risk of a number of infectious diseases (20, 21).

In a couple of studies, moderate alcohol consumption has been associated with either no risk or a decreased risk for upper respiratory infections, while excessive alcohol intake increased the risk of respiratory infections and acute illnesses (22, 23).

These protective effects of moderate drinking on the immune system may be due to the antioxidants and polyphenols present in beer or wine (24, 25, 26).

It’s important to stress that although moderate consumption of beer and wine may provide some benefit to the immune system in healthy adults in some studies, excessive alcohol consumption is still not recommended given the serious health risks associated with exceeding more than 2 drinks a day (27).

To reduce the risk of harm from alcohol-related disease or injury, healthy men and women should drink no more than 10 standard drinks a week and no more than 4 standard drinks on any one day according to Australian drinking guidelines.

The less you drink, the lower your risk of harm from alcohol.

9. Supplements worth mentioning 

Some supplements have shown to strengthen your immune system that include:

• Vitamin C - Vitamin C is an antioxidant that supports immune function. One review of over 11,000 people who took 1 – 2g of vitamin C a day had a reduced duration of the cold by 8% in adults and 14% in children. However, vitamin C did not prevent the cold (28).
  
  
• Vitamin D - Vitamin D helps regulate the immune system, and a deficiency may increase your risk of getting sick. However, if you have adequate vitamin D, supplementing may not provide any benefit (29).
  
  
• Zinc – Zinc is required for the healthy development and function of immune cells. A 2017 review of 575 people with the common cold found that supplementing with more than 75 mg of zinc per day reduced cold duration by 33% (30).
  
  
• Garlic - Garlic contains an active ingredient called Allicin that may support the immune system. One 12-week study in 146 people reported that supplementing with garlic reduced the incidence of the common cold by about 30%. More research is still needed though (31).
  
  
• Turmeric - curcumin is the active ingredient in turmeric that is both an antioxidant and anti-inflammatory compound that reduces inflammatory chemicals that can support the immune system (32). 
  
  
• Omega 3 fatty acids - Omega 3 fatty acids found in hemp seed oil, algae, and fatty fish (eg. sardines, salmon, mackerel) help to fight inflammation and may be beneficial to the immune system (33, 34). 

In most cases you don’t need to supplement and it’s ideal to get these nutrients from foods as much as possible!

10. Get outdoors!

When you spend time outdoors your body produces vitamin D via UVB exposure from the sun.

Vitamin D has an important role in modulating the cells of the immune system. While vitamin D deficiency is linked to poor immune function and autoimmune conditions (35). 

Furthermore, a study by science direct found that spending time outdoors can help to boost your mood and reduce stress. Positive mood improved within 10 min of natural environment exposure that can reduce stress and take the load off your immune system (36).

To learn everything you need about getting enough vitamin D click here!

11. Weight maintenance

Being overweight or obese is characterised by inflammation that is associated with the increased risk of chronic health conditions such heart disease, diabetes, and cancer.

Being overweight also impairs the function of the immune system by decreasing immune cell numbers and reducing your immune response (37).

You can help to reduce your weight through regular exercise and by eating less food by eating smaller portions and making sure you have enough protein that induces satiety (feeling full) and increases your metabolism. 

To learn more about how to increase your metabolism and support weight loss click here 

Take-home message

Now you know that you don’t need to make any radical changes in your life to support a healthy immune system.

Instead, you can do simple things like getting more rest, managing stress, eating a well-balanced diet, exercising regularly, and getting outdoors that can all help to boost your immune system!

Take your time and implement one step at a time, otherwise you may become overwhelmed! If you need further support best to speak to your healthcare professional.

*While eating a healthy diet and living a healthy lifestyle can support a strong immune system it will not make you immune to the COVID-19 virus.

If you have any questions or need support with your health, feel free to email our head nutritionist Ben at ben@13seeds.com.au 

Disclaimer: 

This article does not constitute as medical advice and does not take into consideration your personal circumstances. Please see your medical professional before implementing the above.

References: 

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256323/
2. https://www.ncbi.nlm.nih.gov/pubmed/30920354
3. https://pubmed.ncbi.nlm.nih.gov/26118561/
4. https://www.cdc.gov/features/sleep/index.html
5. https://www.ncbi.nlm.nih.gov/pubmed/31504080
6. https://pubmed.ncbi.nlm.nih.gov/24798553/
7. https://www.ncbi.nlm.nih.gov/pubmed/22474371
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9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614697/
10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352291/
11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024874/
12. https://www.nature.com/articles/s41467-019-09964-7
13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2515351
14. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-3010.2008.00705.x
15. https://onlinelibrary.wiley.com/doi/full/10.1111/apt.13248
16. https://nutritiondata.self.com/facts/custom/1352377/1
17. https://www.betterhealth.vic.gov.au/health/healthyliving/physical-activity-its-important
18. https://www.sciencedirect.com/science/article/pii/S2095254618301005#
19. https://www.cdc.gov/tobacco/data_statistics/sgr/50th-anniversary/pdfs/fs_smoking_overall_health_508.pdf
20. https://pubmed.ncbi.nlm.nih.gov/7576156/
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33. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3191260/
34. https://pubmed.ncbi.nlm.nih.gov/7490601/
35. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
36. https://www.sciencedirect.com/science/article/pii/S0160412019325929
37. https://pubmed.ncbi.nlm.nih.gov/22429824/