When I first started in clinical practice, I was staggered by the number of people, both adults and children, who suffered from gastrointestinal distress. In fact, digestive complaints are amongst the most common reasons for individuals seeking medical help. There are more than 200 over-the-counter remedies for digestive disorders, many of which create additional digestive problems in their place, and that’s not even the worst news. Many medics do not seem to be aware that once we have a compromised digestive system, it can play out over our entire bodies, leading to allergies, arthritis, autoimmune conditions, acne, chronic fatigue, mood disorders, intolerances, autism and more. So having a healthy gut is absolutely central to our entire health, since it is, ultimately, connected to almost everything that happens in our bodies. And so, to help people treat chronic health problems, I almost always start with fixing their gut. First, let me explain a little bit about what happens in there.

Your digestive system is responsible for breaking down and absorbing all the food we eat, and then subsequently delivering nutrients to your body’s cells. Over a lifetime, the average person ingests more than 25 tons of food; however, as well as providing nutrients, this food may also contain damaging bacteria, viruses, and toxins. The gut wall – or mucosal layer – has the unique role of absorbing health-promoting nutrients and molecules, while also providing protection to the body by preventing the entry of toxins or pathogens into the blood stream.

The mouth: Digestion begins in the mouth with the mechanical action of chewing food and the chemical action of saliva. Chewing breaks down food and increases the surface area available for saliva to work on. Saliva is mostly made of water, but also contains the enzymes salivary amylase and ingual lipase, which begin breaking down carbohydrates, proteins, and fats. Many people do not chew their food properly, which creates additional stress on the rest of the digestive system. It is important to master the art of eating mindfully to begin the digestion process correctly.

The Stomach: Chewed food is passed down into the stomach, which acts as a reservoir for food and mixes the food bolus with HCL (hydrochloric acid) and enzymes. The stomach produces HCL to create an acidic environment that favours the initial breakdown of proteins. In addition to this, many microorganisms and pathogens are destroyed by this low PH. Consuming too much or too little acid can cause digestive complications and symptoms, which can be very similar (burping, reflux and bloating), though generally people assume they have too much acid. An amazing statistic that I read recently claims that approximately 44% of adults self-medicate with antacids or other similar medications. These drugs function by decreasing or neutralising the level of stomach acid by blocking the function of the parietal cell that produces it. However, here is the real deal breaker, your body produces stomach acid for a number of good reasons, and requires it to stay healthy. Adequate HCL is necessary to start the digestion process of proteins, activate digestive enzymes, keep bacteria from growing in your small intestine, and help you absorb important nutrients like calcium, magnesium, and vitamin B12. It begs the question, ‘what are the long term consequences of taking a product that significantly inhibits these actions?’

The small intestine, pancreas & gall bladder: Once your food has spent some time in the stomach being liquefied into a substance called chyme, it is methodically squirted into the first part of the small intestine – the duodenum. The very presence of chyme in the duodenum triggers the release of two hormones: cholecystokinin and secretin, which serve the following functions:

1. Sending a message to the brain, telling us that we are full.

2. Telling the stomach to slow down the emptying process.

3. Triggering both the pancreas to release digestive juices to further breakdown food molecules and the gall bladder to release bile for the emulsification of fats.

If the first part of the digestion process in the stomach has not been effective, most commonly because there is insufficient levels of HCL to kick-start this whole process off, then these subsequent triggers do not occur. As a result, the small intestine digestion and its absorptive function become compromised. Digestive enzymes from the pancreas do not flow as readily and the gall bladder may not release bile to emulsify fats. Ultimately, this results in food molecules not being broken down into their smaller components to be absorbed. These remaining larger molecules can start to ferment and/or irritate the lining of the gut wall causing damage and a condition called ‘leaky gut’. In addition, they can lead to an overgrowth of bacteria in the small intestine, which should not ordinarily have such a large population of bacteria. For many more people, low-grade overgrowth of bacteria in the small intestine leads to bloating, gas, abdominal pain and diarrhoea.

The gut wall and ‘a leaky gut’: In a healthy gut lining (mucosa), the epithelial cells that make up the mucosa are tightly packed together like a brick wall, and have contact points called tight junctions. This surface is semi-permeable, thereby allowing properly digested food molecules to pass across into the bloodstream. They also simultaneously act as a barrier, preventing larger damaging molecules like partially digested food, foreign particles, and pathogens, such as infectious bacteria or viruses, from entering. The absorptive surface is formed from finger-like projections called villi, which are coated in cells called enterocytes that complete the final digestive process and absorb the nutrients into the bloodstream.

Both the enterocytes and tight junctions can become damaged by toxins, such as bacterial and fungal by-products, incomplete digested food, food additives, alcohol, over-the counter drugs like NSAIDs, and foreign microbes. When damaged, the tight junctures between the cells expand, creating a ‘gap’, enabling the absorption of these larger and toxic molecules across the gastrointestinal tract mucosa into the bloodstream and general circulation. These now antigenic molecules can provoke immune reactions and cause a heavy burden on the liver to try and detoxify. This contributes to a toxic load of the system and symptoms, and conditions start to occur.

Interestingly, ‘beneficial bacteria’ in the gut act as the housekeepers for the digestive tract. They coat the entire surface of the gut, providing another layer of protection from invaders and toxins by providing a natural barrier, and producing a lot of anti-bacterial, anti-viral and anti-fungal substances. Read more on gut bacteria below.

Gut immunity: Approximately 70 per cent of our total immune system is located within the GI tract. The primary purpose of this gut immune system is to provide a first line of defence – termed ‘innate immunity’. The cells that are embedded here are constantly in contact with foods, microbes, and toxins. As such, they make innumerable immunological decisions every day. As the gut makes its decisions, it then relays information from the innate to the adaptive and systemic immune system. The gut is where health begins, and is also home to a plethora of numerous species of bacteria that form a symbiotic relationship with the host (us!) to establish ‘tolerance’ and immune balance.

The human body is home to trillions of micro organisms that we call microflora or gut flora. The largest colonies of microbes live in our digestive system, where a healthy adult on average carries 1.5-2kg of bacteria in their gut. They play a number of vital roles in the body:

  • Keeping the bad guys out: Having the right levels of ‘beneficial or essential’ bacteria helps to prevent more opportunistic or pathogenic microbes from taking up residence in our gut. Some of the beneficial bacteria also actively produce antibiotic-like substances, anti-fungal and anti-viral substances that dissolve membranes of viruses and bacteria.
  • Modulate and condition the immune system: Approximately 70 per cent of our immune system is located in the gut wall and gut flora has a dynamic influence on this immune system – literally priming it for appropriate action. Our immune system has two different modes of attack based on the invader. One mode is for dealing with organisms like bacteria, viruses and fungi that get inside our cells. The second is for attacking pathogens found outside our cells. A healthy immune system is able to switch back and forth between these two modes, but if one side becomes too dominant, it can result in the immune system running amok and a host of symptoms from allergies to autoimmune responses can be the net effect. Amazingly, the gut flora is vital for helping to maintain this delicate balancing act between the two sides and, as such, aiding immune tolerance

Essential or beneficial flora: These bacteria are referred to as our indigenous friendly bacteria. The main members of this group are: Bifidobacteria (Bifidobacterium bifidum), Lactobacteria (Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus rhamnosus), Propionobacteria, Peptostreptococci and Enterococci.

Opportunistic flora: This is a large group of various microbes: Bacteriods, Peptococci, Staphylococci, Streptococci, Bacilli, Clostridia, Yeasts, Enterobacteria, Fuzobacteria, Eubacteria, catenobacteria and many others. There are around 500 various species of microbes known to science so far, which can be found in the gut. In a healthy person, their numbers are limited and are tightly controlled by the beneficial flora. Each of these microbes is capable of causing various health problems if they get out of control.

Transitional flora: These are various microbes that we swallow every day with food and drink. When the gut is well protected by the beneficial bacteria, this group of microbes pass through our digestive tract without doing any harm, but if the population of the beneficial flora is damaged and not functioning well, this group of microbes can cause disease.

Today, there are many factors that can damage the beneficial gut flora and knock our digestive system off balance.

  • Our low fibre, high sugar, processed food, nutrient poor, high calorie diet that feeds the wrong bacteria and yeast in the gut leading to a damaged ecosystem
  • Overuse of medications that damage the gut or block normal digestive function, such as anti-inflammatories, antibiotics (it takes between 4 to 8 weeks depending on the species of beneficial bacteria to re-establish in the gut after taking antibiotics), acid blocking drugs, and steroids
  • Chronic low-grade infections or gut imbalances with overgrowth of bacteria in the small intestine, yeast overgrowth, parasites, or even more serious gut infections
  • Toxins damage the gut, such as mercury and mould toxins
  • Lack of adequate digestive enzyme function, which can come from acid blocking medication use or zinc deficiency
  • Stress can alter the gut nervous system, causing a leaky gut and changing the normal bacteria in the gut

Fortunately, there are some simple dietary and lifestyle changes we can all make to give our digestive organs a helping hand, reduce stress and restore balance. You can read about these changes in Better Digestion Guide: Healing Your Gut.

My ‘Better Digestion Guide’ takes an in depth look at what goes on in our digestive tracts, how imbalances can occur and gives simple strategies to address these imbalances.

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