Gut Health and the Modern Way of Living

Think of all those well-known phrases with gut at the core – 'a gut reaction', 'gut decision', 'spill your guts'. Gut is a well-used word and yet do we ever stop to think about what we are really referring to? The technical definition, if you choose to look it up on one of the world's most well-known search engines is 'the alimentary canal, especially between the pylorus and the anus, or some portion of it.' Even that definition seems rather ambiguous – further proof that this book needed to be written in the first place. What is our gut? What do we mean when we talk about 'good gut health'? Where do probiotics fit into all of this?

Ask most people what 'probiotics' are and they might refer to the 'tummy-friendly bacteria' in the small yogurt drinks they've seen advertised. Some might talk about natural yogurt providing good bacteria and others might refer to probiotic supplements that can be taken when you have an upset stomach – this idea of course being based on a commonly held belief that there's a 'pill for an ill'. In fact, if your health-related news antennae are particularly active, then you may have picked up on the fact that some nutritional experts are referring to probiotics as the 'health foods of the year'. As a whole range of ready-made probiotic foods hit the market from kefir to kombucha and recipe books on the subject of fermented foods gain popularity, it really is time to discover what probiotics actually are.

Perhaps one reason for such confusion is that we are skewed towards thinking of ill health as something that can be fixed by medication rather than focussing on prevention of illness. The prevention of ill health is behind many of the food preparation practices from more traditional cultures, which tend to produce naturally probiotic-rich foods. Names like Lactobacillus acidophilus, Lactobacillus brevis or Lactobacillus casei might not have be familiar to the people making kefir on a regular basis in the past they just knew it did them good. More traditional cultures where probiotic-rich (fermented) foods are commonplace view these foods not only as necessary but also as preventative.

According to the World Health Organisation 'health is a state of complete physical, mental and social wellbeing, and not merely the absence of disease or infirmity.' But our more modern food processing techniques don't really lend themselves to this ethos.

Our lifestyles today include the consumption of large amounts of sugar-loaded, additive-filled, overly-processed foods, and high levels of the wrong kinds of fats such as trans fats (found in cheap baked goods) and oxidised fats created by heating or frying food in vegetable oils. Yet it wasn't so long ago that we were enjoying slow-cooked stews and casseroles, and eating nose-to-tail – having the whole animal including the liver, tongue, kidney and heart, drinking live yogurt which hadn't had the 'good bacteria' added in because the natural methods of production had put it there in the first place, and consuming sourdough bread that took five days to develop even the 'starter' that was used in place of modern, fast-acting yeast.

When you think that much of what we consume today, such as breakfast cereals, fizzy drinks, low-fat spread, artificial sweeteners, excess alcohol, and even infant formula was unknown to our bodies just a hundred years ago it makes sense that the introduction of these new compounds might explain the increase in food intolerance and allergies. Our gut simply can't cope.

Add to that the ubiquitous prescription of antibiotics, the long-term use of birth control pills, and the use of over the counter pain relievers and possibly other medication, the gut (or 'microbiome' as we should refer to it) is left damaged and that exposes us to more infections and makes us vulnerable to other health issues too.

It doesn't stop with food and medication either. Our gut bacteria vary depending on age, gender, geography, hygiene, stress, birthing method (C-section or vaginal delivery) and our first foods (breast milk or formula). They can all determine what bacteria colonise our gut.

An imbalance of gut bacteria has been related to a wide variety of ailments that may seem entirely unrelated to the gut. As we will see over the course of this book, it can lead to mental health problems, autism, high cholesterol, achy joints and many autoimmune conditions to name a few.

This concept of gut imbalance has been so widely studied by scientists that it has its own name. It is called 'dysbiosis', a word first coined by scientist Dr Eli Metchnikoff in the early 1920s. It is derived from two words 'symbiosis' meaning living together in mutual harmony and 'dis' which means not. Yet we cannot talk about the health issues related to dysbiosis without referring briefly to the connection between an imbalance of gut bacteria and a condition called Leaky Gut Syndrome.

Leaky Gut Syndrome

This is a condition which is not always recognised by mainstream medical professionals. However, the evidence of its existence and its link to a number of illnesses is mounting rapidly. Leaky gut occurs when the gut becomes overloaded by stress, toxins, drugs, pathogenic bacteria and poor food choices. When this combines with a low number of beneficial gut bugs and a lack of diversity then gaps can form between the cells lining the gut, called epithelial cells.

A leaky gut is not a loyal gut. It might shut the gates to beneficial nutrients while welcoming dangerous bacteria inside. Gaps in the periphery of the gut also let in viruses which might otherwise be dealt with by the gut bacteria. Now that these bacteria and viruses can access the body via the bloodstream they pose a far bigger threat to health. This movement across the lining of the gut into the bloodstream is called 'bacterial translocation' or BT for short.

What gut bacteria do for you?

We are discovering so much more about the role of gut health in our overall health thanks to scientists now focusing specifically on this area. We've realised that our gut bacteria are instrumental for some seriously life-sustaining functions. Some of the most important functions identified so far relate to:

• Immune system function

• Controlling inflammation

• Improving the rate of detoxification

• Improving mood by playing a role in the production of our 'happy hormone' serotonin

• Making vitamins, including B vitamins like folate, biotin and B12 as well as vitamin K2

• Preventing the development or worsening of leaky gut

• Improving nutrient absorption, especially of iron, zinc and magnesium

You are what you eat

Each human has a very individual health profile and balance of bacteria. However we are all very much the product of our environment, and specifically our dietary choices, when it comes to bacterial balance. You may have heard of the phrase, 'You are what you eat'. This adage seems more apt now than ever. Study after study has revealed a clear link between dietary choices and gut bacteria. Our food choices have a profound effect on the diversity of our gut microbes – and more diversity means a healthier microbiome.

One 2015 study showed that Americans who ate diets formed predominantly of processed fast foods had significantly limited bacterial diversity in their guts when compared to South Africans whose diets were higher in fibre. The fascinating part of this particular study was that within two weeks of switching diets the situation started to improve for those who normally ate a fast food diet and were now eating more like the South African participants. Equally the markers for good gut health were lower in the South African participants who had switched to the American diet after the same two week period. The speed of positive change related to dietary changes is exciting as far as disease prevention is concerned and even as far as achieving optimal health. The speed of microbiome health recovery seems extraordinary but it is another reminder of just how adaptive and responsive the human body can be to positive health interventions.

What we cannot fail to identify is that the modern Western diet is very far away from the real food diet of our ancestors. When I say ancestors I am not talking about those members of our families who lived millions of years ago. I am instead referring to those who may simply have lived a hundred years ago. If they were to walk into a modern supermarket or a fast food restaurant of today would they even recognise what we are eating as food? Even if they did, they may question where it has come from and what we have done to it. As a society, we are very far removed from the source of our food. Most of us have no idea where our meat is farmed or our vegetables picked. Furthermore we have no idea about the processing that goes on before a particular food in its packaging makes it onto the shelves of our favoured supermarket.

A case in point is cured meat. Curing would have been a very familiar process to our ancestors a century ago. They would probably have cured meat, fish and vegetables themselves. However as demand increased for cured meats and sausages so the process moved out of the home and into the factories. The use of nitrates in this environment became commonplace but was unregulated until scientists realised that the nitrosamines, that form when nitrites are present in high concentrations and the product is cooked at high temperatures, could be cancerous. In fact, according to World Cancer Research Fund analysis those who eat the most processed meats have around a 17% higher risk of developing bowel cancer than those who eat the least processed meats. To give you an idea of the potential impact of nitrosamines on health of a population, since the European Union stipulated that cured products should contain no more than100mg of nitrate salts per 1kg of meat, the rates of stomach cancer in Europe have fallen considerably. Our modern tastes are beyond our knowledge of what's healthy and actually what's doing us harm.

You are a product of your environment

It appears that where we live in the world and what we may be exposed to in our environment can play a part in the gut bacteria we play host to. For example in a New Scientist article regarding the possibility that gut health and Parkinson's disease may be closer linked than we initially thought, it was noted that farmers exposed to certain pesticides, and people who get their drinking water from wells – which might be contaminated with pesticides – are more likely to get Parkinson's. It was concluded that these chemicals can also damage nerves in the gut so the relationship between gut health and the development of Parkinson's may be initially triggered by environmental toxins. Many studies have shown that where populations have lived in a largely unchanged culture and environment for some time their gut bacteria appears to be both stable and healthy. However when industrial foods grown using chemicals, processed in factories and created for mass consumption came along and when medications such as pain relievers and antibiotics entered the frame changed and the gut bacteria of the population changes too.

Mood and gut health

Serotonin is well known as a neurotransmitter. However, what is less well known is that an estimated ninety per cent of the body's serotonin is produced in the digestive tract. Taking this into consideration, when you think of people who have poor digestion they often have low mood problems too. It is hardly a surprise. In fact, probiotics have been shown to improve anxiety in animal-based studies. Further human studies have revealed that probiotics can have a direct effect on brain chemistry, impacting feelings of anxiety or depression. A 2013 study even showed a relationship between prebiotic supplements and anxiety in so far as the prebiotics appeared to alter the way that people processed emotional information. The relationship between probiotics and prebiotics is discussed later on in this book but it seems that both can have a positive effect on mind symptoms.

How our understanding of gut bacteria and disease is advancing

Our understanding of what other diseases may be linked to gut health is advancing at a pace. The possible relationship between Parkinson's and the gut was first discovered about ten years before the New Scientist article. This was when autopsies revealed the very substance associated with Parkinson's - clumps of synuclein that were normally found within the brain, were discovered in the nerves of the gut. Of course, it would be hard to find out if these clumps of fibres travel from the gut to the brain in human beings but tests have been carried out on mice that show this to be the case. The mice in one particular study became less agile, something that happens to humans with Parkinson's disease. Scientists made a further correlation between Parkinson's sufferers and gut problems in the period leading up to diagnosis. People diagnosed with Parkinson's often report digestive issues, most commonly constipation, in the ten years leading up to the first tremors. Our knowledge relating to probiotics shows that they may be able to positively influence the gut bacteria of potential Parkinson's sufferers and could change the outcomes of this illness.

Another disease that has recently been linked to changes in the microbiome is type 1 diabetes. In a 2016 study, researchers followed children who were genetically predisposed to the condition. They found that onset for those who developed the disease was preceded by a drop in microbial diversity. Scientist Alexandra Paun, in her 2016 paper, goes as far as to suggest that the association between changes in gut microbiota and both diabetes type 1 and type 2 is so strong that microbe-derived medication could potentially be used for prevention and/or treatment of both conditions in the future. Furthermore, a group of researchers from the US Argonne National Laboratory discovered that gut bacteria (in particular bacterial enzymes) could affect the process of breaking down sugars into glucose. This discovery could have implications for the treatment of diabetes.

'Much of the medicine prescribed today focuses on human, rather than bacterial, cells. We target human enzymes with drugs, but we don't often target bacterial enzymes. If someone has diabetes, doctors prescribe drugs to control their production of glucose. We might want to consider whether bacterial enzymes that produce glucose should also be targeted.' Andzej Joachimiak, Argonne National Laboratory

In summary, our modern lifestyles and dietary choices are having a major impact on our overall health. The places we choose to live, the jobs we do, the stress we put our bodies under, the foods we eat all play a part in the development of our gut bacteria over time and this can in turn affect our future health in ways we probably never thought possible. We must open our minds to the possibility that 'poor gut health' doesn't mean a bit of tummy ache or the odd bout of diarrhoea or constipation. Nor does it mean a little indigestion or acid reflux when we have consumed too many spicy meals or alcohol. Gut problems really do extend way beyond the gut. As we go through this book, we shall go on a journey to understand exactly how important the bacteria in our gut really are to our overall health and wellbeing. We will look at what happens when we have too few 'good' and too many 'bad' bacteria present and how we might be able to use our knowledge to address imbalances that may be the cause of major disease. To do this properly, we shall have to rely on the hard evidence available, the science behind the myths, and not our "gut feeling".

A Journey through the Digestive System

In order to appreciate the role of probiotics and prebiotics in gut health, it is important to understand how the digestive system works. It might help to think of the upper gut as an almost sterile, digesting, carnivorous organ (like a dog's or a cat's), evolved to deal with meat and fat, whilst the lower gut (large bowel or colon) is full of bacteria and is a fermenting, vegetarian gut (like a horse or cow's), evolved to digest vegetables and fibre.

Your digestive system is essentially a tube that runs from your mouth to your anus. The tube runs through various different 'departments' and each has a role to play for optimal digestion to take place. If everything runs smoothly and the departments work effectively together then things go well. If not, then digestion will not be effective and ill health may well result.

The mouth

Digestion begins in the mouth. This is where the food first starts to get broken down. The processes involved in this first stage are grinding and chewing of the food by our teeth and enzymatic breakdown (our saliva contains enzymes that start to break the food down into smaller molecules so that our body can absorb the nutrients in the food efficiently). Saliva is sometimes produced even when we start to think about tasty food, but certainly when we smell it, see it and start to cook it. In fact, both cooking and eating slowly (or 'mindfully') can aid overall digestion. Yet, many of us don't cook and we certainly don't tend to eat slowly or mindfully either. Modern lunches tend to be a rushed affair. Often the same food will be eaten day in day out, in large gulps as we respond to urgent emails or check out social media updates. Breakfast is often on the run as few people have time to sit down and eat before they leave the house. And evening meals are frequently eaten in front of the television or as we're glued to devices. None of these eating environments are really suited to optimal digestion because, put simply, your body is focused on things other than digesting food.