We are what we eat right? Well yes, but more accurately, we are what we eat, drink, digest, absorb, think and believe.

Here is the third instalment in this series.

So, once we have cleaned up our food and beverage intake, we are all set, right? Well, while it’s a massive step in the right direction, it’s not quite the full story.  A good diet is only as good as our digestive system. You may be eating some of the most wholesome foods and sipping on water from the purest of mountain springs, however if your digestive system is not functioning properly, your body may only be getting a fraction of the nutrients you put into it. Not only that, a poor functioning gut may also be having knock-on effects to your immune system, nervous system and much more.

Our digestive system is (in my opinion) one of the most fascinating parts of the human body and really is the “epicentre” of good health. Not only does it convert our food into molecules for our body to either use or store (an amazing process itself); but it also communicates with our brain in what is known as the “gut-brain connection or brain-gut axis”, and can therefore influence and impact our learning, memory and mood. This communication is bi-directional, and our brain can also influence our gut, it’s motility, secretions, permeability, and our all-important gut microbiome.  A.M.A.Z.I.N.G. right? But a little more about that later.

Digestion begins before we even put that first bite into our mouths. The smell, look, or even thought of food releases saliva and other digestive enzymes, priming us to eat. How many times have you smelt something cooking (sautéing onions always gets me), and started salivating, or heard your stomach rumble when you see a delicious plate of food? Our digestive system is switching on before we even begin eating.

The digestion process really kicks off however in our mouth, where chewing increases the release of saliva which (along with the chewing process itself), helps break down our food before we swallow it. Our food then travels down our oesophagus, into our stomach (where it is further broken down by digestive enzymes); and then onto the small intestine, the main site of nutrient digestion and absorption (1).

The small intestine is one impressive structure. It is approximately three metres long and, if spread out, it’s surface area would cover a tennis court! (1). To help absorb as many nutrients as possible, it has several impressive features such as millions of microvilli (tiny hairy finger-like projections rich in cells which capture and digest the nutrients passing through the intestine). It also contains numerous immune cells and enzymes that act as a defence system against bacterial infections and foreign substances that we may ingest with our food (1).

The pancreas, gallbladder and liver assist the small intestine by providing digestive enzymes and bile (which help to further break down the food), as well as a rich blood supply to help carry the absorbed nutrients to the rest of our body (1). Our nervous system and certain hormones also play a role, influencing the release of enzymes and substances required for nutrient digestion and absorption, and also help regulate our gut’s motility (1).  It’s an impressive and intricate process!

And then there is the large intestine (or bowel). By the time material reaches here, most nutrients have been absorbed, and the large intestine primarily absorbs water and some electrolytes, readying the material for defecation (1). However, the bowel is far from being just a tube for waste production. It is in fact where some key functions occur, not the least of which is the magic of the gut microbiota.

While the topic of the microbiome really deserves its own separate blog, it is important to mention here. Our microbiome refers to the collective populations of trillions of microbes that we all have in our bodies (2). While they reside almost everywhere from our skin, to our mouth, nose, and genitals; the majority are found in our gut, and are particularly prevalent in our colon (2). The types of microbes that make up our microbiota are varied and will differ from person to person, as they are influenced by numerous factors, including our birth, how we were feed as an infant (breast-fed vs formula), our environment, antibiotic use, and of course, our diet (2,3).

Gut microbes perform important roles in our body; helping ward off pathogens, regulating our immune system, and maintaining our gut mucosal lining (which acts as an important barrier between our gut and our bloodstream) (2,3). They also help us produce Vitamin K and some B vitamins AND produce energy, by fermenting the complex carbohydrates we eat (especially fibre), to produce short-chain fatty acids, which our body then uses as fuel (4).

If that wasn’t enough, there is a growing body of research showing that our gut microbes also have the ability to communicate with our brain, and may influence our sleep, stress response, anxiety levels, mood, learning ability, and tolerance to pain and may be implicated in various conditions from IBS to depression and even Parkinson’s disease (3). Fascinating right?! While it is still not completely clear how the microbes achieve this, it is thought to be via their interaction with our nervous system and immune system (3).

With such a large number of interactions and complex processes involved, it’s easy to appreciate why our digestion may not always be as optimal as we might like. Illness, infection, injury, disease, medications, alcohol, drugs, stress, hormone imbalances, over-eating, and poor dietary practices can all impact on any of the aspects of our digestive system; and can result in inflammation, malabsorption, sluggish digestion, increased gut permeability and inappropriate immune responses – leaving us feeling tired, unwell and may eventually lead to disease.

So, how can we keep our digestive system happy and healthy? Well starting from the top there are a few simple things many of us can do:

Prime your digestive system before you start to eat: As the smell, look and even thought of food can switch our digestive system on, make sure you include lots of colour, delicious smelling food or just foods that appeal to you, into your meals. Bitter foods such as rocket, radish or beet leaves, and even citrus can also help stimulate our digestion, so you may like to start your meal with a little of these or add them to your meal to aid your digestion (5).

Avoid eating when stressed or upset – with our gut and brain so intrinsically linked, it’s important to remember that your digestive system is not primed for eating when your brain is in “flight or fight” mode. Our blood supply is literally pushed to our heart, brain and extremities, readying us to fight or flee that tiger, bear, or boss (???). Before eating, try to calm your mind and body into the “rest and digest” mode, so your heart and adrenalin aren’t pumping a mile a minute – your digestive system will thank you for it!  A few deep calming breaths in and out before eating may just do the trick.

Eat slowly and mindfully –  we all know someone that almost inhales their food, or maybe you’ve been guilty yourself (I know I have sometimes!). Eating quickly or on the run, has almost become the norm in the busy-ness of life, with “on the go” meals and “quick bites” a reflection of our seeming need to eat fast. Another problem is multi-tasking while we are eating, whether it’s eating lunch at our desk while getting that report written, eating in the car as we rush between appointments, or just eating in front of the TV or laptop as we sit down to dinner. Whatever the case, we are not often not actually being mindful and consciously thinking about what we are eating let alone how we are eating. Take time out to eat your meals, away from distractions. Savour and enjoy each mouthful of food, rather than mindlessly eating. You will find that you not only relax more and aware of the beautiful flavours and textures of your food but will be more conscious of how full you feel and avoid indigestion and overeating.

Chew Chew Chew – Chewing your food properly is one of the easiest ways in which you can help your digestion. By breaking your food into the smallest fragments, it means the rest of your digestive system doesn’t have to work overtime to break the food down for absorption, and you are helping your body to try get as many nutrients from the food as possible.

Reduce your portion sizes –  Be mindful of how much you are eating at each meal. Not only does overeating add extra calories to our waistlines, it also puts extra stress on our digestion, stretching our stomach and making our digestive system work overtime to break down the amount of food eaten. If you tend to fill your plate to the brim, try using a small plate for your meals, and leave the seconds for lunch the next day – perfect!

Eat more fibre – fibre is your digestive system’s best friend (remember that along with other complex carbohydrates, it provides the fuel from which our large intestine makes energy). It also acts as a broom for our large intestine (sweeping up all the waste as it passes through), helps to soften and provide bulk to our stools, and makes us feel full (6).  Most plant-based foods such as fruit and veges, as well as nuts, seeds, wholegrains and legumes are great sources of fibre (which is mostly found in the skin or outer layers hence why it’s important to keep the peel on and unrefined – just as Mother Nature intended).

Include prebiotic and probiotic foods into your diet – prebiotics are non-digestible plant-based material that our gut microbiome feeds on…they act like fertiliser for the good bacteria in our gut (7).  Numerous vegetables and fruits contain prebiotic compounds, including onions, garlic, asparagus, artichokes, leeks and bananas – how easy are these to include in your diet! Probiotics are living organisms including bacteria and yeasts that are beneficial to our body in large amounts(7). They can be found in fermented foods such as natural yoghurt, miso, kefir, kombucha, sauerkraut and some cheeses. While food-based pre-and probiotics are great for preventative health, if you are looking to address a particular condition you may be best supplementing to ensure you are getting a therapeutic dose and that you are taking the right strain of probiotic to address your particular condition or ailment. Come see me if you feel like this is you!

References

1. Gropper S, Smith J, Groff J 2009, Advanced Nutrition and Human Metabolism 5th edn, Wadsworth, Canada
2. Jandhyala S et al 2015, “Role of the normal gut microbiota”, World Journal of Gastroenterology, 21(29), pp. 8787-8803
3. Mayer E, Tillisch, K, Gupta A 2015. “Gut/brain axis and the microbiota”, The Journal of Clinical Investigation, 125(3): 926–938
4. Besten G et al 2013, “The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism”, Journal of Lipid Research, vol. 54(9), pp.2325 – 2340
5. Pitchford, P. 2002 Healing with Whole Foods 3^rd edn, North Atlantic Books, California
6. Rodriguez R. et al 2006, “Dietary fibre from vegetable products as source of functional ingredients”, Trends in Food Science and Technology, vol 17. pp. 3-15
7. Tomasik P & Tomasik P 2013, “Prebiotics and Probiotics”, Cereal Chemistry, vol 80, pp.113-117