Bacteria are controlling your life!

You’ve heard of “you are what you eat” but I’m here to tell you that’s wrong.

Because the truth is, you are what your body absorbs, not what your body consumes.

This is why digestion (and the trillions of bacterial cells and other microbes involved in the process) are so important. So much so that the bacteria in your gut, known collectively as the gut microbiota, are sometimes referred to as a virtual organ for the human body.

As well as digestion, your gut microbiota has a crucial function to play in healthy functioning of your body, such as immune function and disease prevention.

Today, we’ll talk you through not only the benefits of a healthy gut microbiota but also what causes an unhealthy gut microbiota as well as the things you can do to improve your gut health.

The Gut Microbiota

The gut microbiota is a complex interaction of over a thousand different species of bacteria sharing a home in the human intestinal tract. Interestingly, there is a lot more to these bacteria than just living there for the free food that passes through.

While a number of the bacterial species don’t provide many benefits to the host, a lot of them actually do.

For a start, as previously mentioned, they play a very important part in digesting our food. In fact digestion of breastmilk and fibre as well as production of Vitamin B and K wouldn’t be possible without these bacteria.

Additionally, the gut microbiota may surprisingly be involved in regulating the human immune system. Having so many bacterial species live harmlessly in the body allows the immune system to adapt to these bacteria in case they decide to try and cause harm.

There is also research emerging which suggests that the gut microbiota is involved in controlling blood sugar and lipid levels as well as stable mental health.

Okay, so gut bacteria are good for you and are needed to keep you healthy… But can they be bad for you?

Well, when the microbiota is in a state of dysbiosis, your risk of health problems increases.

Dysbiosis and Disease

To understand dysbiosis, we first need to understand that the gut microbiota is a complex community of thousands of bacterial species, each interacting with one another and contributing to the overall function of the microbiota.

So when there is an alteration to this balance when there is either too many of certain organism or too little of others, the whole community becomes imbalanced. This is called dysbiosis and can greatly affect the microbiota since the interaction between organisms becomes impaired.

Dysbiosis usually occurs due to some species of bacteria growing faster than normal, leading to the death of other bacterial species because of competition. The other way dysbiosis occurs is due to some species dying too fast or not being able to replicate at fast enough speeds, which allow other species to grow in its place.

Both situations result in a disproportion in the number of bacteria of each species, compared to a healthy microbiota and are often caused by external factors such as antibiotics.

Although the mechanism isn’t currently fully understood, this imbalance leads to potential damage to the function of the microbiota as well as leading to a variety of other diseases.

The diseases associated with a state of dysbiosis include arthritis, IBD, peptic ulcer disease, diarrhoea, eczema and even colon cancer.

The severity of the diseases linked with dysbiosis emphasises the importance of having a healthy gut microbiota as it shows that they play a much larger part in maintaining your health than just helping you to digest certain foods.

It’s also interesting to note that there is a strong link between the microbiota and weight management. In fact, in an experiment where mice received a faecal matter transplant (where the gut microbiota is transferred to another individual) from either a healthy human or an obese human, the mice that received the transplant from the obese humans gained more weight than the mice that received the transplant from the healthy humans.

This is most likely due to the influence that the microbiota has upon leptin production, which is a hormone which controls hunger levels.

What Causes Dysbiosis?

Now we know that a state of dysbiosis is undesirable and can lead to various diseases, we can look into the causes of dysbiosis, in order to fully understand how to look after the gut microbiota.

As previously explained, dysbiosis is usually caused by external factors which lead to either excess growth or reduced growth of one or multiple species, affecting the balance of the community.

But how is this balance established in the first place?

Generally, the microbiota is established shortly after or during birth and reaches full maturity when the individual is around 3 years old. Therefore the main factors involved in determining the microbiota composition are diet as an infant, exposure to maternal microbes, route of delivery (caesarean vs vaginal delivery) and genetics.

After the balance is established, it usually remains balanced.

So what causes the community to become unbalanced leading to dysbiosis?

Well, there are a few factors which can change the balance, most of which being external factors. For a start, even though diet generally doesn’t change the microbiota too much, long term changes to your diet can definitely affect the composition.

Antibiotics, however, tend to have a much stronger effect upon the microbiome as they are very effective at killing certain bacterial species. This, in turn, allows other bacterial species to dominate the microbiota, reducing overall diversity.

The excess use of antibiotics early on in life should especially be used with caution, since the microbiome is still developing. This is also most likely why the use of antibiotics in children is linked with IBD, asthma, obesity and other diseases.

Another factor which can potentially lead to dysbiosis is stress. Not only this, but stress can further lead to poor gut health as it can alter the intestinal permeability, meaning that materials which shouldn’t enter the bloodstream can enter much easier.

Additionally, stress can lead to inflammation of the gut, and affect the digestive secretions that the gut releases, meaning that digestion becomes compromised.

How to improve your gut health

So far in this article, we’ve established that dysbiosis of the gut bacteria is bad, and therefore one of the most important things we can do to keep our gut healthy is to avoid dysbiosis.

Although, your body will generally attempt to do this anyway, there are a few things you can do to help.

For a start, you should be careful about how you use antibiotics. Sure, if you’ve got a genuine bacterial infection and the doctor has recommended you to take them, then definitely do so. However, you don’t need to be pressuring your doctor to give you antibiotics every time you become ill. Additionally, if you live in a country where antibiotics are available without a prescription, please consult a doctor to see if you actually need to use them.

Next up, is stress management. As previously mentioned, living in a state of stress is awful for your gut health, amongst other negative effects. In our optimising testosterone blog post ( we also discussed some of the ways in which to tackle stress. This was because of the detrimental effects that stress has upon testosterone levels.

Finally, optimising your diet is very important in keeping your gut healthy. This means that you should eat plenty of fibre which the bacteria can feed upon, as well as including non-fibrous fruits and vegetables and trying to eat a wide variety of non-processed food.

You should also be minimising the amount of processed food, sugars and artificial sweeteners that are present in your diet, as they can all negatively affect the microbiome.

Finally, to further boost your gut bacteria, you can include prebiotics and probiotics into your diet.

Prebiotics are indigestible material that your gut bacteria can feed off. These include bananas, onions and garlic. They are therefore great to help you to maintain a healthy gut microbiome.

Then you have probiotics, which are actual live bacteria that are good for your gut and are associated with good gut health. Good sources of probiotics include kimchi, yoghurt and sauerkraut.

You can also buy probiotics in a pill if you feel like you really need to fix up your gut microbiome. The most effective use of probiotics would probably be when your gut is in, or at risk of becoming in, a state of dysbiosis, for example when starting a course of antibiotics.


Your gut bacteria form an extremely complex community which are essential for good health and help with your immune system, blood glucose control, weight management and prevention of disease.

When the number of species in the community changes, the health of your gut changes and you become more prone to diseases such as asthma, IBD, obesity and arthritis.

You can improve your gut health by being careful with antibiotic use, avoiding stress, increasing fibre in your diet, avoiding processed food, sugars and artificial sweeteners as well as supplementing with prebiotics and probiotics as required.

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