Your Microbiome…much more than just some friendly bacteria

Your Microbiome…much more than just some friendly bacteria


The microbiome is big news in the health world. The study of those friendly bacteria in our gut has made enormous advancements and has changed the way we understand our immune system and our health.

What is the microbiome?

Our microbiome is the collective name for the bugs that live in our gut and all the genetic material that belongs to them. Our bodies contain 100 trillion of them, weighing over 4 pounds in our guts alone. The quantity, diversity and specific species of microbes is dependent on a number of factors. The first 2 to 3 years of life are very important in the establishment of your microbiome. Starting with birth, our gut starts to be cultivated with microbes from our mother’s birth canal, followed by those present in breast milk.  Growing up on a farm, having a pet, and playing in nature as much as possible, are all positively associated with having an abundant and varied microbiome.

Conversely, your early childhood years can be responsible for negative changes to your gut flora. Caesarean sections, formula feeding and recurrent antibiotics are not gut-friendly. Repeated doses of antibiotics in childhood are associated with an increased risk of type 2 diabetes and obesity. There are clearly many situations where caesareans and antibiotics are life-saving or unavoidable and how we were born or how we give birth to our own children is often out of our control – we can only do our best. It certainly has changed my professional decision making with regards to prescribing antibiotics, adding to the existing concern about over-use and resistance.  Some experts recommend (and I believe it is common medical advice in other countries) that if a young child does need antibiotics, then a course of probiotics at the same time, along with some fermented foods like yoghurt or kefir would be a good idea.

But why is all of this important?  What does our microbiome do?

The full extent of the marvel of this newly discovered organ is probably beyond the scope of this article, but it is important to start thinking about looking after your gut and making decisions based on maintaining it’s health.  We have learnt that it forms 70% of our immune system, that it produces many hormones and neurotransmitters that are important in managing our mood, that is has an important role in regulating the inflammation in our bodies and hence impacts our risk of chronic diseases and that changes in the numbers and type of microbes can have positive and negative effects on our weight.

How to better my microbiome?

Fortunately, there are a lot of simple and practical things that we can do to improve and support our microbiome and help to support our immune system, reduce our risk of chronic diseases and help to regulate our mood.  You may immediately think of probiotics, those live bacteria in the form of drinks or capsules that you hope may set up a new life in your gut.  Unfortunately, many never it make it as far as the large intestine and so are rendered useless.  There is a lot of hype around probiotics and unfortunately little science behind most of them.  They can be a good idea however when using antibiotics, you just need to choose wisely.

The food approach…

It is much better to have a ‘food first’ approach. Start with limiting the amount of processed and sugary foods, then aim to eat at least 5 different vegetables, ideally of 5 different colours every day. I heard the other day that we have increased our broccoli consumption by 940% in the past 25 years. Now we all know that we should eat our greens but are you aware of the amazing properties that broccoli has? Broccoli is one of a group of foods known as pre-biotics that provide the fibre that our gut bugs thrive on. Others include onions, garlic, bananas, leeks, cauliflower and Jerusalem artichokes. The gut bugs feed on this fibre in the large intestine and produce various by-products including short-chain fatty acids, or SCFAs. These SCFAs, of which butyrate is one of the most studied, are anti-inflammatory. This means they can help to reduce inflammation which can lead to heart disease, Alzheimers and arthritis. Cruciferous vegetables like broccoli also have an role in your immune system in the small intestine. So we are wise to have increased our broccoli intake so much!

It is encouraging to know that when you start to eat differently, your microbiome will start to change within 2 to 3 days. Incorporating 5 different vegetables into your diet every day will accelerate the process of optimising it. The different colours found in these foods contain different compounds known as phytonutrients. We are only just starting to understand the amazing benefits of these substances but do know that they help heart health, fight cancer cells and reduce inflammation and brain ageing. Polyphenols, a particular type of phytonutrient have powerful antioxidant effects, which means they help to mop up the damage caused by everyday natural body processes, keeping your body in harmony. These can be found in berries, green tea and flax seeds, but also in red wine, good quality chocolate and coffee – so feeding your microbiome can also feed your soul!

Whilst manufactured probiotic products may not be worth it, adding fermented products to your diet is a good natural option – especially if homemade!  Foods such as yoghurt, kefir, kombucha, kimchi and sauerkraut come ready made with lots of ‘good bacteria’ already present and so are a healthy addition to any diet.

The exercise approach…

It isn’t just food that can affect our microbiome. There is evidence that exercise can increase microbial diversity. There is also evidence that our gut microbes have their own circadian rhythm and that allowing a good period of fasting every day between dinner and breakfast of at least 12 hours can increase the number of specific species associated with better weight control and insulin sensitivity. Prioritising sleep is hugely beneficial to lots of areas of health and gut health is no exception.

I anticipate that in the future, the research coming out in this area will be fascinating, with possible practical implementations to use microbes in the treatment and prevention of disease, maybe with personalised probiotic supplements. Faecal transplants are already used successfully in the treatment of resistant cases of a bowel infection called Clostridium difficile…who knows what use it may have in the future! I think for now, the message is to look after your gut through adopting healthy lifestyle habits. Eat the rainbow, limit processed and sugary foods, spend time in nature or doing the gardening, prioritise sleep and exercise, and allow a good period of time each night for your gut to rest. Now, pass the broccoli!

Dr Claire Carroll
Private GP, Fulham