If you had told me at the start of my university degree that one day I would be not only genuinely interested in, but also blogging about gut health I would have said you are crazy! But the truth is, our gut is absolutely glorious and it is essential that we take great care of it.
My fascination with the gut is quite recent and I myself am still learning about the important role it plays in not only digestion but also other systems in the body. Let me share with you a bit about how the gut works and how the gut microbiome aids not only weight loss but overall physical and mental health.
How The Gut Works
The main role of the gut is to turn food into fuel and eliminate unwanted toxins from the body. This role is not independent to the rest of the body; they are in constant communication with other organs, particularly the brain (this is known as the gut-brain axis, a communication system that links the cognitive centres of the brain with the peripheral functions of the intestines. But more about this later!).
Although digestion technically starts in the brain and mouth, the organs we commonly think of when we consider the gut are the small intestine and colon (large intestine).
The small intestine is a muscular tube almost seven metres long. It converts the semi-solid food matter from the stomach into liquid form, to make it possible for nutrients to be absorbed into the bloodstream. The small intestine has three segments. In the first, the duodenum, food breakdown continues with the help of enzymes squirted from the pancreas, liver and gall bladder, and by contracting muscles that move it through, in a process known as peristalsis. In the other two sections, the jejunum and ileum, nutrient absorption from the now-liquid food into the bloodstream takes place via tiny projections called villi and microvilli that line the intestine. The length of the small intestine allows time for nutrients passing through to be absorbed.
(Excerpt from The Mystery Gut by Professor Kerryn Phelps, 2017)
Large Intestine (Colon)
The colon is part of the digestive tract required to process the waste from a liquid state into a more compact product that's more easily excreted. This is mostly achieved by transit time (it takes on average 36 hours for waste to make it through almost two metres of colon), water absorption and re-absorption, and gut bacterial activity. This is also where foreign bacteria are dealt with, vitamins are synthesised and waste particles are sorted for recycling or excretion.
(Excerpt from The Mystery Gut by Professor Kerryn Phelps, 2017)
What about the Gut Microbiome? Why is it so important?
Did you know our gut is ALIVE?! It is not simply the individual organs small intestine and colon, but rather home to trillions (yes TRILLIONS) of microorganisms which live in the gastrointestinal tract. This is referred to the Gut Microbiome (gut flora) and they actually play a very important role in the body!
Now normally when we hear the word bacteria we think of disease and illness, however there is a range of beneficial bacteria that are essential for the body to maintain good health. These aren't only found in the gut, they also inhabit our skin, mouth and urogenital tract, but the greatest number and diversity are found in the gut. In fact, there are between 500-1500 species of microorganisms in each individual, ranging from commensal (neutrally existing), symbiotic (mutually beneficial), and pathogenic (harmful to the body). How amazing is that!
As each individual microbiome is developed both during and after birth, the flora inside a newborn baby's gut is influenced by it's mother and other people who are in close contact, geographical location and environmental conditions.
Did you know: Your own gut flora is so unique to you as an individual that it has been compared to your fingerprint!
These guys are far from passive, they have a range of roles and jobs to do in the body due to their genetic contribution (and by this I'm referring to the fact that they have an amazing collection of genes, which is far greater to the number humans have).
These diverse functions include:
⦁ The break down of food components such as sugars, starches and fibre in order for their nutrients to be absorbed.
⦁ Fermentation of dietary fibre to produce short-chain fatty acids (SCFA) which are in turn beneficial for energy metabolism. SCFA's also aid the absorption of minerals such as calcium, magnesium, zinc and iron.
⦁ Production of vitamins B and K, which the body then absorbs, as well as amino acids.
⦁ Maintaining the strength of the mucosal lining which acts as a protective barrier to the gastrointestinal tract, keeping out unwanted bacteria and toxins, and providing immunity. a healthy gut microbiome is needed in order for a strong immune system to develop, as the microorganisms in our gut help maintain the delicate balance required.
⦁ Production of hormones and neurotransmitters, which are chemicals that send specific signals to the brain. in fact, the gut produces around 50% of the dopamine (calming hormone) in the body and over 70% of serotonin (mood hormone) in the body.
With such a wide range of jobs to do, no wonder it is important to keep our insides healthy and these little guys happy!
How to create a healthy gut microbiome
There are a number of simple ways to positively influence our flora composition, these include:
⦁ Eating well: a healthy diet is one of the easiest ways to take care of our gut flora! Aim for whole foods that are rich in fibre and are low in processed sugar, including fermented food and pro- and pre-biotics. Avoid foods that are also high in trans fats, food additives and colourings, preservatives, and dietary advanced glycation end-products (dAGE's). dAGE's are known to increase oxidative stress and inflammation in our cells, this is where prebiotics come in handy as they stimulate the growth of beneficial bacteria, thus protecting against dAGE's! No wonder health professionals constantly preach about the goodness of vegetables!
⦁ Reducing exposure to toxins: this includes not smoking and limiting excessive alcohol intake. Also be aware of unnecessary pharmaceuticals and antibiotic intake (anti = against, biota = living organisms) as this can upset the balance of beneficial bacteria in the gut.
⦁ Reducing stress: easier said than done I know! High levels of the stress hormone cortisol can increase bad bacteria and decrease the beneficial bacteria in the gut. Practice mindfulness and meditation whenever possible, or try yoga, adult colouring books (these are still in, right?) or having some down time.
⦁ Getting plenty of good-quality sleep and avoiding jet lag where possible: keep to your natural circadian rhythm (get up and go to sleep with the sun) to reduce the stress hormone cortisol.
Other strategies include getting regular exercise and physical activity, getting in touch with nature by spending time in a forest or on a farm, and being cautious of excessive hygiene (throw away the antibacterial wipes!).
I hope you have found this introduction to the gut helpful! Please have a look through the resources below for more information.
Kerryn Phelps, 2017, The Mystery Gut, Pan Macmillan Australia, Sydney
Kate Callaghan, 2016, Holistic Nutrition, Finch Publishing, Warriewood
Astrup, A, Brahe, L and Larsen L, 2013, 'Is butyrate the link between diet, intestinal microbiota, and obesity-related metabolic diseases?', PubMed, vol 14, no. 2, pp. 950-959.
Blaut Et Al, 2010, 'Gut Health: predictive biomarkers for preventative medicine and development of functional foods', British Journal of Nutrition, vol 103, pp. 1539-1544.