Colds and flu

Updated 05 October 2017

Your gut is the cornerstone of your immune system

A recent study has found that our modern lifestyle, diet and overuse of antibiotics are causing an increasing disruption of the gut microbes that are the basis of our immune system.

What is going on in your intestines or gut is an essential part of your health. In fact, your gut and your immune system are very closely linked, and 70 to 80 percent of your immune tissue is situated in your digestive tract.

Dealing with pathogens

Because our intestines are inside our bodies, most people don’t realise that it forms a protective barrier between our bloodstream and the external world. What’s inside your gut is actually “outside” your body.  

The gut has to deal with the pathogens in everything you ingest and therefore needs to have an effective immune system in place to ward off attacks and prevent illness.

Read: The poisons and heavy metals in our food

The gastrointestinal immune cells are known as “Peyer’s patches” and protect the mucous membranes of the small intestines against infection by releasing white blood cells (T-cells and B-cells).

Boosting the action of the immune cells are certain strains of gut flora that prevent pathogens from being absorbed. This is why it is so important to have colonies of “good” bacteria in the gut. In fact, without the right balance of gut flora your body cannot maintain good health.

Breastfeeding is very important because it colonises the gut of the newborn baby with good bacteria from the mother which is associated with a decreased risk of allergies and other problems of the immune system.  

Reducing colds and flu 

Apart from serious disorders like autoimmune diseases a strong immune system reduces the number of colds and flu and other antigenic conditions that plague the human race.  

When the integrity of the gut is compromised, it can lead to a “leaky gut”, which means that the body is no longer protected against “invaders” like undigested food, gluten and bacteria which have passed through the “holes” in the gut lining.

Read: Gluten sensitivity

A leaky gut gives rise to food intolerances which can eventually lead to autoimmune conditions and other problems.

A few examples of problems caused by a leaky gut are:

  • Crohn’s disease
  • Multiple sclerosis
  • Eczema
  • Arthritis
  • Migraine headaches
  • Psoriasis
  • Depression

The importance of the link between diet, gut bacteria and immunity cannot be underestimated. More and more people are realising that eating the wrong kinds of food can have a negative effect on the bacteria in your gut and make you more susceptible to a range of diseases.

Steps to improve immunity

Research has revealed that a diet rich in whole, unprocessed foods will encourage the growth of good bacteria in the gut, helping to establish a strong immune system. 

Read: Stress bad for good bacteria

There are other specific steps that can improve gut-related immunity:

  • Eating probiotic foods containing Acidophilus, L. casei and L. rhamnosus
  • Increasing fibre intake
  • Increasing Omega-3 fatty acids and decreasing the levels of Omega-6 in the diet
  • Moderate amounts of exercise
  • Enough sleep
  • Lowering stress levels

A study undertaken by Oregon State University has come to the conclusion that the role of gut microbes in the immune system “may hold the key to dealing with one of the more significant health problems facing people in the world today”.  

Disruption in 'crosstalk'

Author of a new report in Clinical Reviews in Allergy and Immunology, Dr Natalia Shulzhenko, emphasises that our intestines contain more immune cells the entire rest of our bodies and that the human gut plays a “huge role in immune function”. According to Shulzenko an emerging theory of disease is that a disruption in the “crosstalk” between the microbes in the human gut and other cells involved in the immune system and metabolic processes.

She adds that things like modern lifestyle, diet and overuse of antibiotics are causing an increasing disruption of the gut microbes that stimulate the immune system and that the chronic inflammation linked to most of the diseases that kill people in the developed world today may begin with dysfunctional gut microbiota.

Read more:

Pre- and probiotics boost immunity

I want to boost my immunity

Common household chemicals bad for kids' immunity


Oregon State University: Gut microbes closely linked to range of health issues (2013).

Science Daily: Gut microbes closely linked to proper immune function, other health issues (2013).

Food Matters: Your Gur And Immune System Connection (2014).

PaleoLeap: The importance of Gut Flora for your Immune System.


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Dr Heidi van Deventer completed her MBChB (Bachelor of Medicine and Bachelor of Surgery) degree in 2004 at the University of Stellenbosch.
She has additional training in ACLS (Advanced Cardiac Life Support) and PALS (Paediatric Advanced Life Support) as well as biostatistics and epidemiology.

Dr Van Deventer is currently working as a researcher at the Desmond Tutu Tuberculosis Centre at the University of Stellenbosch.

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