There is emerging evidence to suggest what is found in our guts can significantly influence our health.

Our digestive system, or gut as we like to call it, starts at our mouth, and works its way through our stomach and intestines until it reaches the end game, our anus! It enables food and drink that we eat to be transformed into smaller parts and transported to where it is needed most and where it can protect, warm, energise and nourish our bodily systems. Most of the work goes on in the background when we are least aware, perhaps asleep, at work or out with friends.

It is the microbes that live in our gut that are doing all the hard work for us. Gut microbes live all through our digestive system, including our skin but the biggest concentration is found in a pocket in the large intestine, called the caecum. It is this area that is known as the gut microbiome. It is an ecosystem of an estimated 100 trillion microbes, of which the majority are bacteria, but also includes yeasts, fungi and viruses. It is a highly complex symbiotic relationship which we do not yet fully understand, but what is becoming clear is that we can influence our microbiome by the way we choose to live our lives, the food we choose to eat and the environment in which we live. In short our lifestyle plays a massive role in the health of our gut and its ability to protect us.

A healthy gut microbiome consists of a massive number of microbes but perhaps equally important is the diversity of the microbes. The larger the number and variety of microbiota within our gut the better able they will be at maintaining health and protecting our bodily systems from disease. The significance of the gut microbiome in preserving life is considered so significant that reclassifying of the gut as an organ in its own right has been called for.

The Microbiota play an integral role in a wide range of body pocesses – digesting food, producing vitamins and essential amino acids, influencing fat and glucose metabolism, neutralising drugs and carcinogens, and building our immune system to help resist infections and reduce the risk of developing a number of chronic diseases. It is now thought that the microbiota even effect our behaviour and cognitive functions such as learning, memory and decision-making.

Peter Deaman 2016 Live Well Live Long

What does the microbiome do for us?

1 It aids the digestion of food

2 It regulates our immune system. A poor immune system has been linked to conditions such as, acne, eczema, allergies, depression, type I diabetes, arthritis, as well as viruses such as Covid.

3 It reduces our risk of getting neurodegenerative diseases. There are suggested links to diseases such as Parkinson’s and Alzheimer’s.

4 It influences the likelihood of developing long term disease. A poor gut microbiome is being mentioned as a risk factor for chronic fatigue syndrome.

5 It is thought to play an important role in the production od neurotransmitters such as seretonin, which is known as our ‘happy hormone’. It could offer protection from stress and anxiety, and depression.

A unique gut microbiome

We all have a unique gut microbiome. Whilst humans share 99% of their DNA, the human gut microbiome is much more varied. Tim Spector et al (2020) of the Zoe app, used by many during Covid, described how unrelated individuals shared 30% of their gut microbiota, whilst twins shared only slightly more at 34%. It appears increasingly that the genes we inherit have less effect on our microbiota than our lifestyle and thus our wellbeing.

What effects the quality of our gut bacteria?

This is influenced by a wide range of factors, including the type of delivery we were exposed to at birth, the method of feeding when we were infants, what medications we ingested (especially antibiotics) and the diet we chose/choose to eat. Perhaps the biggest influence on our gut bacteria that we have the power to change, is what we put in our mouths. A diet low in fibre, fruit and vegetables will not provide a gut environment that is conducive to a large and diverse population of microbes.

Stress can change the number and diversity of our gut bacteria which then can affect how our immune system works. This could explain why certain conditions, such as eczema, flare up when we are stressed.

Our environment has an impact on our gut health. It appears not being super clean is a benefit. Third world agricultural populations have a far stronger microbiota than the western world. Playing in mud is now seen as positive for the health of our gut diversity. The number of social contacts we have also seems to influence the diversity of our gut microbiome, probably due to the way we interact with people.

How can the gut microbiome be improved?

1 Start by increasing the amount of fibre, fruit and vegetables you have in your diet. It encourages ‘good’ bacteria to multiply by fermenting the fibre, which the bacteria will then feed off. High fibre foods include; beans, pulses, (such as chickpeas and lentils) wholemeal bread and whole grain foods, brown or whole rice, nuts and seeds, oats and jacket potatoes, as long as you eat the skin!

2 Include prebiotics and probiotics in your diet. Dietary probiotics include plant fibres, the non-digestible carbohydrates found in the skins, leaves, pith and seeds of fruit and vegetables. These ferment in our guts on their way through, feeding the bacteria. It has been described as adding humus rich bacterium to our gut environment. Dietary probiotics contain micro-organisms that are thought to benefit and support the microbiota of the digestive tract. Probiotics include, live yoghurt, Kefir (fermented milk drink), cheese made from unpasteurised milk, unpasteurised sauerkraut, brine fermented vegetables, unpasteurised miso (fermented soy bean), unpasteurised soy sauce, Kombucha (a fermented drink made from tea) and kimchi (Korean fermented cabbage). Research has shown that children who were given probiotics through the winter months, for 6 months, were less likely to miss school, had fewer fevers, fewer runny noses and fewer antibiotics.

3 Eat Fermented foods such as live yoghurts, sauerkraut, kimchi, seaweeds are considered beneficial for the gut as the contribute ‘good’ bacteria to the gut.

4 Aim for natural vaginal birth that allows the infant to come into contact with the mothers amniotic fluid and faecal matter, is considered to play a vital role in the development of the child’s immune system, potentially preventing diseases such as, coeliac disease, gastroenteritis, allergies and type I diabetes. More of theses diseases are found in children born by caesarean section.

5 Breast feed infants when possible. There is evidence to show that the microbiota from this milk is directly seeded into the infants gut, providing him/her with a multitude of health benefits including a protection against diarrhoea, morbidity and mortality, and less risk long term from diabetes, obesity, allergies and autoimmune diseases, compared to formula fed babies.

6 Reduce your stress levels whenever you can. Stress may cause the digestive process to slow and be disrupted. This can lead to poor digestion of food, leading to the growth of unwanted bacteria. It is also thought that the gut-brain axis influences mood.

7 Limit alcohol intake. This is not what you may want to hear but alcohol can change the proportion of ‘good’ bacteria to ‘bad’ in the gut.

8 Stay physically active. Exercise is thought to boost the levels of gut microbes producing a substance called butyrate. This has many benefits including increasing the hormones that make you feel full after eating, to encouraging gut motility (movement). It supports the immune system and reduces inflammation. Butyrate is found in butter, fibre and prebiotics.

9 Reduce your sugar intake. A diet high in processed sugar can promote inflammation and reduce the number of ‘good’ bacteria.

10 Eat a rainbow diet of fruit and vegetables each day. Try to count 5 different colours on your plate at meal times. Colourful fruit and vegetables supply polyphenols which benefit gut health, as they stimulate the reproduction of a huge number of probiotic gut microbiota.

11 Limit the amount of antibiotics prescribed where possible. Taken appropriately antibiotics can be life saving by killing off the bacteria that is harming you. However, they also kill of other bacteria, including those that are considered to be ‘good’. If you need a course od antibiotics make sure you complete the course, then supplement your diet with probiotics and fermented foods for a few weeks to repopulate your gut.

In summary

Our symbiotic relationship with our gut microbiota has evolved over the millennia. The microbiome is a highly complex ecosystem within our gut, and only now are we starting to appreciate how wide reaching its effects on our wellbeing are. The lifestyle we live in the UK has led us to eat more processed food, use more antibiotics, and keep our towns, our homes and ourselves as clean as possible. The way we live now is changing our microbiota, perhaps forever. It is recognised that a healthy gut microbiome is beneficial in improving and maintaining many areas of our health, such as increasing our immune system, reducing autoimmunity, reducing neurodegenerative diseases, and lowering the risk of stress and depression. Changing our diet to improve our microbiome is perhaps the single most significant thing we can do to improve our health. The role of the gut microbiome in maintaining human life on earth is only now starting to emerge.