Gut Feel: How Your Digestive System Affects Your Immune System

October 2017, Customer Care Team


With winter looming, many of us reach for the Vitamin C supplements and chicken soup to keep colds and flus at bay. While these two classics are certainly an important part of our winter wellness prescription, the real key to fighting the office lurgy actually lies in your gut.

With winter looming, many of us reach for the Vitamin C supplements and chicken soup to keep colds and flus at bay. While these two classics are certainly an important part of our winter wellness prescription, the real key to fighting the office lurgy actually lies in your gut.

Yes, you read that right. Over 70% of our immune system is actually located in our digestive system.

It makes sense when you think about it. Consider everything your hard-working digestive system is exposed to: the carrots grown in your back garden, the meat from a farm, the biscuit out of an open packet, the coffee cup that touches your lips…nothing is totally sterile. We are exposed to literally thousands of bacteria every single day. Without a strong digestive system, we would be sick almost every time we ate!

Your gut is an incredibly important barrier to the outside world.

How our digestive system affects our immunity

Our digestive system contains literally billions of bacteria – in fact up to two kilograms worth! These bacteria do a myriad of things that protect our health, from influencing our mood to determining the size of our waistline[1].

But one of the most important things they do is control our immune response.[2] Our gut bacteria and immune system have a symbiotic or mutually beneficial relationship – the bacteria help our immune system stay strong, and our immune system provides protection for the gut bacteria.[3]

Our gut bacteria seem to fight bugs in a number of ways[4], including:

  • Strengthening the gut wall. The barrier between us and the outside world is a layer of cells that line the gut known as epithelial cells. Maintaining the integrity of these cells is essential to preventing bugs passing through into the bloodstream. Unfortunately the modern lifestyle can make this barrier permeable (leaky), allowing pathogens to pass through and creating a situation known as leaky gut syndrome. Leaky gut syndrome has been linked with a range of health conditions from poor immunity to auto-immune disorders and allergies. Our gut bacteria help to keep this physical barrier strong, preventing leaky gut syndrome. They also provide an important chemical barrier to bugs – the bacteria keep our digestive system relatively acidic, making it an unwelcoming environment for pathogens.
  • Regulating inflammation. Inflammation is an incredibly complex process but it has a huge influence on our health. Researchers are now recognising that many chronic health disorders are actually related (at least in part) to inflammation – from cardiovascular disease to asthma. Keeping inflammation to a minimum is essential to maintaining good health and preventing disease.


The bacteria in our digestive system seem to directly affect the level of inflammation in our bodies. Our digestive systems contain both ‘good’ and ‘bad’ bacteria. Before you get worried, ‘bad’ bacteria are harmless, provided they are kept in check. The balance between the two seems to be important in managing both inflammation and immunity.

Just as our gut bacteria needs to be balanced, so too does our immune system. It must be strong enough to fight bugs but not so strong that it begins to attack our own body system. When the immune systems over-reacts, we can develop auto-immune diseases and allergies. Inflammation is strongly linked with both of these conditions. Maintaining the right balance of bacteria in our gut and preventing inflammation is integral to a balanced immune response. [5]

  • Producing antimicrobial chemicals. The bacteria in our digestive system also help fight bugs by producing strong chemicals. For example, one species produces an antibacterial substance that fights E. coli, Salmonella, and several different types of bacteria that cause respiratory infections).[6]

Tipping the balance

As discussed, the balance between harmful and beneficial bacteria in our digestive systems seems to be important in maintaining a strong immune system.

Unfortunately, the modern lifestyle of stress, processed foods, alcohol, sugar, antibiotics and other medications can upset this precise balance, harming the good bacteria and allowing bad bacteria to proliferate. This unhealthy balance of bacteria impairs immune function, promotes inflammation and affects our digestive system.

So how do we build good gut bacteria?

The good news is we can easily improve the balance of bacteria in our digestive system with quality supplementation, good nutrition and lifestyle techniques.

Sugar, high-fat and processed foods promote the overgrowth of bad bacteria, while fruit and vegetables, legumes and whole grains help friendly bacteria thrive. Managing stress and getting enough sleep also seem to be important.

What about probiotics?


A common recommendation to improve our gut health is to eat foods containing sources of good bacteria such as yoghurt and sauerkraut or take probiotic supplements. While there is certainly no harm in this, the trouble is that the probiotics are often destroyed by our stomach acid before they can reach the small intestine.

A more effective means of boosting your good bacteria and supporting your immune system is consuming prebiotics and soluble fibre. These substances can make it through the harsh acidic environment of our stomach and actually provide food for the good bacteria in our small intestine.

Prebiotics and soluble fibre are special kinds of fibres found in certain fruit and vegetables, rice bran, oat bran, legumes, linseed (flaxseed) seaweed, nuts and seeds. The body doesn’t actually digest these fibres, the bacteria in our gut break them down and ferments them.

Kiwifruit – The digestion and immunity superfood

Nature has given us a veritable superfood for supporting both immunity and helping maintain a healthy balance of gut bacteria. Naturally high in both soluble fibre and prebiotics, and rich in Vitamin C, Kiwifruit is a powerhouse for winter immunity.

Unfortunately, most supermarket kiwifruit is artificially ripened to increase shelf-life - a process which also affects kiwifruit’s potency. In addition, you would need to eat the entire kiwifruit - flesh, seeds and fuzzy skin for optimum digestive benefits.potency. You would also need to eat every part of the kiwifruit fuzzy skin and seeds as well as flesh to receive all the digestive benefits. Xtend-Life’s Kiwi-Klenz provides all the benefits of kiwifruit in a convenient supplement. Many competing supplements only use kiwifruit pulp – not the skin and seeds – meaning you are missing out on many of the powerful benefits. By using every part of the fruit you can be sure you receive all the benefits.

Xtend-Life’s Kiwi-Klenz supports digestive function in four ways:

  • Contains prebiotics to help feed good bacteria
  • Rich in enzymes to help better digest and absorb the food we eat
  • High in soluble fibre to keep things moving
  • Contains phenolics which discourage the growth of bad bacteria.


[1] Sanmiguel, C., Gupta, A. and Mayer, E. Gut microbiome and Obesity: A Plausible Explanation for Obesity. Curr Obes Rep. 2015 Jun (4(2):250-261.

[2] Geuking MB, Köller Y, Rupp S, McCoy KD. The interplay between the gut microbiota and the immune system. Gut Microbes. 2014 May-Jun;5(3):411-8.

[3] Chassaing B, Kumar M, Baker MT, Singh V, Vijay-Kumar M. Mammalian gut immunity. See comment in PubMed Commons belowBiomed J. 2014 Sep-Oct;37(5):246-58. doi: 10.4103/2319-4170.130922.

[4] O'Hara AM, Shanahan F. Gut microbiota: mining for therapeutic potential. Clin Gastroenterol Hepatol. 2007 Mar;5(3):274-84.

[5] Wu HJ, Wu E. The role of gut microbiota in immune homeostasis and autoimmunity. Gut Microbes. 2012 Jan-Feb;3(1):4-14.

[6] The Importance of Gut Bacteria for your Immune System.

Leave a Comment

Topics you might be interested in

Preventing The Flu Naturally

November 2017 by, Customer Care Team

As the days get shorter and the evenings cooler, it is time for the flu to creep around. Following a particularly severe flu season in Australia, experts are predicting a...

Read More

Fighting the winter blues

October 2017 by, Customer Care Team

Seasonal low mood or depression is a recognised medical condition, believed to be due to an imbalance in neurotransmitters, particularly serotonin, melatonin and dopamine. This imbalance can perhaps be linked...

Read More