The Gut. Explained.

Did you grow up with your mother saying “you are what you eat”? I did, and now I tell her “You are what you digest and absorb”. This is fundamental to the premise that our digestive system is where good health begins, because it’s responsible for transporting the nutrients in the food we eat to the cells of our body.

Digestive health (also referred to as gut health) is now an area of significant interest in the field of integrative health. If you look to the ancient Indian medical system of Ayurveda digestive health was considered fundamental then too. Over time we lost our way.

Could you describe the basic function of the gut?

I actually find that for most, they can't. In its simplest form, the digestive system is one long tube running between the mouth and anus. Food travels from one end of the tube to the other and in that process the digestive system has three key functions to play: provide a barrier of defence from the outside world, effectively break down the food being consumed and ensure maximum absorption & retention of the nutrients (micro and macro) in that food.  When either of these processes fail, the effects of sub-optimal digestive health occur.

Barrier of Defence

The defensive action of the digestive system is carried out in a few ways. Firstly, the incredibly acidic nature of the stomach (the most acidic part of the body) is this way so that pathogens and parasites, potentially lingering in the food we consume, have little chance of surviving and travelling further.


When the pH of the stomach is affected, perhaps due to stress, medications and/or food intolerance, it can increase risk of parasitic infection as well as conditions such gastroesohageal reflux disease (GERD), inefficient breakdown and nutrient deficiency. Particularly B12, iron and iodine levels can be affected.


The physical barrier provided by the lining of the gastrointestinal tract (GIT) protects against pathogens, bacteria and undigested foods making their way from the outside (the gut) to the inside (the blood stream). When this physical barrier is compromised in a process known as ‘increased intestinal permeability’ so too is optimal health. Increased intestinal permeability (also often referred to as leaky gut) can set off a cascade of inflammation which if left unmanaged will manifest in food reactivity, poor immune function, autoimmune conditions, skin conditions (acne, psoriasis and dermatitis), weight gain and/or nutrient deficiency.

Effective breakdown of food

Breakdown of food occurs before even eating as the thought, sight and smell of food triggers the release of oral and gastric secretions crucial to the digestive process. Chewing food is another component of digestion often overlooked. Food travels the oesophagus from the mouth to the stomach, so the more chewing to have been done means more surface area for gastric secretions (hydrochloric acid and enzymes) to do their work. However, by far the greatest amount of digestion takes place in the small intestine.


The ineffective breakdown of food either at the level of the stomach or small intestine will manifest in bloating, reflux, loose bowel motions, constipation (or flipping between the two), gas, bloating and/or discomfort. Stress, poor eating behaviours, food intolerances and bacterial imbalance in the small intestine will all affect the effective breakdown of food.

Maximum absorption and retention of nutrients

Afterall, we strive to consume a nutrient dense diet so body cells may receive the tools they require. If nutrient absorption is affected due to poor breakdown/digestion or increased intestinal permeability, it won’t matter how many superfoods or supplements are being consumed, you ‘can’t outrun poor absorption’.


When nutrient absorption is affected it manifests in stagnant weight, poor nutrient status, low energy levels, poor recovery from exercise, low mood, insomnia, skin conditions, poor memory, brain fog and/or compromised immunity. A tell-tale sign of compromised absorption is poor nutrient status despite supplementation.

Although the digestive system continues to function under a range of less than ideal circumstances, for ultimate digestion and therefore health it’s crucial to be conscious of what affects the three key areas of function. They include stress, poor diet, medications (particularly proton pump inhibitors), hormone replacements (including the oral contraceptive pill), antibiotic use, food intolerance, irritable bowel disease, autoimmune conditions and lastly (but certainly not least) the health of the gut microbiome.

What about the gut microbiome?

It’s now widely appreciated that the gut microbiome is home to more bacterial cells than cells of the body. Most bacteria are symbiotic, which means we live in harmony with them and in return they support us. Bacteria in the gut assist in digestion (especially lactose), regulating bowel motions & peristalsis, immune function, mucosal health (barrier integrity) and the manufacturing of certain nutrients. The gut microbiome is even considered to play a role in regulating blood pressure, hormone balance and a healthy metabolism.

Where to From Here?

For anyone walking into my clinic looking for assistance with fat loss, immune function, optimising a plant based diet, sports performance, hormone balance and/or skin issues, digestion is always, always discussed.


For those of you relating to some of the signs and symptoms of sub-optimal digestive health, hopefully this helps in providing you with direction. If you need assistance from here, I would love to support you. Book in for a 15-minute Complimentary Consultation so we can meet before you get started.

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