Microbiome and the mind
An exploration of how your body health impacts your brain.
How much do you know about your microbiome? Chances are not too much! Yet, it impacts so much of your mental and physical health. In the following article, local Ian, will explore the microbiome and it’s affect on your health and how you can hack your system for a good gut, and as a result, a better mind!
Definitions and background
Microbiome: the community of microorganisms associated with animals and plants, we all have our own microbiome.
Microorganism: any organism that is too small to be seen with the naked eye, generally these are bacteria.
Bacteria: simple single cell organisms, typically around 2/1000 of a mm in size.
Bacteria were the first life to evolve on earth, plants, animals and humans appeared much later.
Animals evolved from and in the presence of bacteria and it is believed that there has always been a strong association between them.
Bacteria can have beneficial and detrimental effects on animals. Today we are talking about the beneficial effects of bacteria specifically in our digestive system (the gut). This is called the gut microbiome.
Bacteria are mainly concentrated in our large intestine, the colon. There is a smaller concentration in the small intestine.
How does our gut microbiome affect us?
The gut microbiome can be beneficial to animals, including humans, in many ways:
🦠 Can help provide nutrients
🦠 Protect from harmful microorganisms
🦠 Influences beneficial hormone function to help with growth, repair and immunity.
The evidence for these beneficial effects comes from studies on laboratory mice: it is possible to raise mice totally free of bacteria so that they have no microbiome in their digestive system. It is found that these mice suffer from poor health, they cannot digest food properly and they have a weak immune system.
If these mice are given bacteria from other mice their health improves within 2 weeks.
Everyone’s gut microbiome composition is unique to them. There are over a thousand microorganisms that colonise the gut and we acquire our specific mixture from upbringing, genetic makeup, diet, lifestyle and social contacts.
Your gut microbiome can be in a healthy state (homeostasis) or in an unhealthy state (dysbiosis). Medical researchers are studying ways to convert a dysbiotic microbiome to a homeostatic one.
However, it is a very complex field to study and scientists are still a long way from full understanding. Unfortunately, there are lots of bogus claims being made online and on social media promoting pills that can improve your microbiome which have very little evidence for beneficial effects. Also beware of test kits claiming to analyse your microbiome and then claiming to give you answers to how to improve it.
However, these are the facts that scientists are sure about:
🧠 If you have a diet rich in plant fibre this favours a healthy gut microbiome with high diversity (a large number of different bacteria species) – diversity is good.
🧠 This is linked to lower risk of heart disease and type 2 diabetes (good ‘metabolic health’).
🧠 It also favours a healthy immune system.
🧠 If you have a diet rich in sugars and fats such as in ultra-processed foods and ‘junk food’ then your gut biodiversity is low, and you are at greater risk of heart disease, diabetes and obesity.
🧠 A change of diet will very quickly lead to a change of gut microbiome, around 5 days.
What is the role of the gut microbiome in nutrition?
Plant fibre is difficult to digest. However, a number of the bacteria in the gut are shown to be able to degrade plant fibre by fermenting it. The products of this fermentation are found to:
🫘 Provide extra calories from plant material
🫘 Promote gut function and gut wall health
🫘 Promote good functioning of other organs
🫘 Reduce inflammation
🫘 Increase sensitivity to insulin (which protects against developing type 2 diabetes)
Also the microbiome organisms are capable of signalling shortages of specific nutrients to the brain which will result in you starting to crave any foods that are rich in that nutrient (note this tendency in pregnant women).
The gut microbiome and the brain 🤯
There is an important connection between the gut and the brain known as the gut-brain axis. Signals go back and forth between them along a nerve known as the ‘vagus nerve’.
So if you are feeling stressed or anxious you will often feel unsettled in the stomach and your digestion can be negatively affected, whilst if you are feeling relaxed and you have a nice meal then you can experience positive thoughts. Also if you have indigestion your mood can drop.
Scientists have yet to fully understand what the microorganisms in the gut are doing but it does seem clear that they can have a strong effect on our mood.
Initially it was proposed that serotonin (the feel-good hormone) was produced in the gut and this went to the brain to improve mood but now it seems that the serotonin made in the gut goes to other parts of the body and not to the brain. The brain makes its own serotonin.
It is now thought that the microorganisms are capable of positively affecting the vagus nerve and also reducing gut inflammation via interaction with the immune system. It seems that if the microbiome is in a healthy state it communicates this to the brain and promotes feelings of well-being.
How do we improve our gut microbiome health?
A key indicator of a healthy microbiome is the number of different species present, also known as diversity. In the unhealthy state the diversity is low. It has been shown that the modern western diet reduces microbial diversity – food that is low in fibre and rich in fats, sugar and meat is not good for you. Additionally it is thought that the use of emulsifier chemicals in many ultra processed foods is harmful to gut bacteria function. We need to be eating more fibre rich foods such as leafy greens and grains (nuts and seeds).
Top Tips!
💙 Eat less ultra-processed foods – ready meals, breakfast cereals, crisps, cakes, biscuits, sausages, burgers and even many supermarket breads. You can recognise ultra-processed food from the types of additives used – emulsifiers, colourings and preservatives are often in the ingredient list. Look for the words ‘modified’, ‘refined’ and ‘artificial’ and be suspicious of any product with a long list of ingredients.
💙 Aim to eat as many different plants a week as you can – ideally 30 different types.
This includes fruits, vegetables, nuts, seeds, herbs, spices and coffee and tea. Beetroot is supposed to be especially good as are berries. This group is known as prebiotics. Potatoes, rice and pasta don’t count.
💙 Aim to eat some fermented foods – live yogurt, kefir, sauerkraut, cheeses (especially blue cheeses). Also kombucha (fermented tea) and kimchi (Korean spicy sauerkraut) are good. They all contain beneficial bacteria and are known as probiotics.
💙 Try to have a 14 hour period of not eating where possible. For example finish evening meal at 6pm and then don’t eat anything else until breakfast at 8am. Gut bacteria apparently benefits from this hungry period.
So in conclusion, your gut microbiome is important to you. Have a think about what you are eating – have a look at the ingredients lists on the labels. Eat more healthy fibrous food and you could soon find an improvement in your mood and wellbeing!
Written by Ian.
