Gut Instincts: Bacteria, Brains And Bodies

Gut Instincts: Bacteria, Brains And Bodies
We are often astounded by the beauty of the world around us, appreciated through the mediums of travel, fashion and art in our every day lives. However some of the most inspiring, fascinating and wondrous things lie unseen within us.


The way our gut works is a booming area of research at the moment, its role previously confined to simply being a bacterial infested waste pipe, could not be further from the truth. Bacteria are one of the most resilient organisms on the planet and our guts are infested with them. Therefore it should be no surprise to learn that they influence our mood, weight and immunity through changes in gene expression, the proteins they excrete into our bodies and the signals they send to our brains. You can’t live without them so it’s time to learn how to live with them.


Gut Active: Fitness and Exercise

Way back in the day when Philosophers were considered the scientists of the modern age, it was believed that we thought with our guts. In some ways, they were not far off and our gut is now known as our second brain, the two communicate very closely through some 100 million neuronal connections. There is more to a healthy bowel than just plenty of ‘good’ bacteria and fewer ‘bad’ bugs – it is all about diversity, something that physical exercise may promote, along with diet. Staying fit also helps with stress and low mood, which are linked to common conditions like irritable bowel syndrome. Stress is an immensely widespread, modern day problem for bacterial undergrowth, overgrowth and lack of diversity. Therefore it is equally important to find some time to relax. Intensive overtraining is not beneficial or necessary and improving your health can include less strenuous options like yoga, pilates or simply walking.


Weight It Out: Fat, Food and Mood

Talking about health is not always synonymous with weight loss. It has been theorised from identical twin studies conducted by endocrinologist Professor Tim Spector, that from the moment of our birth, the way our gut will colonise could strongly be associated with our inherited genes, and not just the environment around us or the foods we fuel ourselves with. This is not to say that the latter does not have any effect at all. It is interesting to note that not only is it common for identical twins to share the same total weight but they also tend to have exactly the same areas of weight distribution.

Everyone’s ‘natural’ body shape is different, just as our heights and skeletal structures vary. I’ll never forget the lecture my endocrinology Professor gave us on ‘hypothalamic set weight’. The theory being that we are all pre-programmed to have a certain weight as our comfortable baseline, one that requires little effort on our conscious behalf to maintain and is tightly regulated by our genes, hormones and the hypothalamus in our brains. With consistent regimes and exercises it is possible to change ones weight, yet for those with a higher set baseline they will forever feel starved and find it much harder to maintain a lower BMI. As nature’s luck would have it, it was also found to be physically possible to shift this hypothalamic baseline up to a higher value, but not down to a lower one.

This constant struggle with weight has led to a wide range of strict diet fads that are meant to become lifetime routine: no carbs, the alkaline diet (our blood is not alkaline, in order for us to stay alive it is an unconsciously controlled, neutral PH 7.35), 5:2 or intermittent fasting to name a few. Did you know that the endorphins released through exercise or from eating delicious food, are also produced by our gut bacteria during times of starvation? Which is why some people can get a brief high from periods of intermittent fasting.

Although it has been noted that a change in diet and lifestyle affects gut flora, studies have also found that different colonies can affect the very food you crave eating in the first place. One of the most interesting studies into bacteria and weight was conducted in obese mice, which had large amounts of a bacteria known as Firmicutes. Lean mice were rich in a type called Bacteroidetes which had anti-inflammatory effects. When faeces from the lean mice were transplanted into the obese mice, they became slim, and vice versa! That doesn’t mean that faecal transplants from Victoria’s Secret models are going to be on sale any time soon, however it clearly demonstrates the complexity of obesity and the role of lowering your firmicutes, in becoming more firm and cute… As a brief summary it is believed that some simple ways to lower these bad bacteria are to reduce sugar, stress and antibiotics (when completely unnecessary, such as if you have a cold). You should eat more fibrous foods such as beans, as well as relaxing and sleeping well.

As a side note many fitness fanatics are quick to adopt very high protein diets, which themselves come with an array of problems from constipation to kidney stones, an increasingly common marker of prosperity. The main culprit is animal protein from red meat, as opposed to vegetable and pulse protein. The WHO made global headlines when it announced last year, that high levels of processed red meats were a clear cancer risk. However very high levels of anything are usually a problem, one of the main issues with diet today is the high sugar levels and lack of variety, leading to lower diversity in our gut colonies. Scientists are also working on ways to tailor diets to individuals by testing their specific flora and using blood tests to measure distinct insulin responses to certain foods. I envisage this becoming hugely popular as technologies develop in future, but for now most of what we have are just rather simple and often ineffective, bacterial supplements.


Bottle It Up: Probiotics and Prebiotics

Probiotics are meant to contain enough live bacteria to in theory, replenish our guts. Prebiotics on the other hand are meant to contain ingredients that feed good bacteria and encourage them to replicate (cellulose / fermented food and oligosaccharides for example). Personally I think the way I’d like to try and keep my gut healthy is not through commercial pills and potions but by eating more unprocessed, wholesome and fibrous foods (i.e. natural prebiotics). I am half Korean and although my mothers generation didn’t grow up with much cultured dairy like yoghurt, the Korean diet consists of a lot of fermented foods – Kimchi cabbage, miso soup and pickles, all believed to be great fertilisers of the GI tract.


Take-Home Doggy Bag

This is such an immensely large and complex field that I couldn’t possibly do it justice within the confines of one article. As with most expanding areas of science, information and advice is ever changing and developing so not every nugget of knowledge can be taken as bible. What is for certain however, is just how diverse and different we (and our gut flora) are from one another. Therefore it is more about building on these basic principles to find out what works best for you in terms of adherence, enjoyment and tailoring a happier, healthier lifestyle to your unique makeup.



This article was written for and published by Health Bloggers Magazine, Issue III : available to download from GumRoad



  1. October 2016 / 11:56 pm

    I truly loved reading this. It was so informative. I read a similar article on Self Magazine’s website a couple of weeks ago but you went much deeper. I am a firm believer in the fact that our gut houses much of our emotion, especially anxiety.

    Thanks so much for posting!

  2. Angel
    October 2019 / 8:01 am


    Thank you for the informative article. I am hoping this will help me improve my gut, I know there are times that we’re not fully aware but some foods can be toxic to our gut. With this in mind we need to take foods that could help us to improve our metabolism and digestion, I hope this probiotics will yield good result on my gut. Here’s another article that I think maybe helpful as well