“Tell me what you eat, and I will tell you what you are.” — Jean Anthelme Brillat-Savarin
When we think about holistic health, many people simply associate the term with diet, exercise and the odd meditation for good measure. We rarely see nourishment of the mind, body and soul as a unified picture and often we overlook the most obvious details linking the three.
Recently science has taken our understanding of our digestive system to a new level, finding huge connections between our mind and body, our moods and our meals and the extensive benefits of (the right kind of) bacteria in our bodies.
The gut microbiome is a collection of micro-organisms made up of bacteria, archaea, viruses, fungi and unicellular eukaryotes. These all reside in our stomach, small intestine and large intestine, with the greatest diversity occurring in the large intestine. We each have trillions of micro-organisms living in our gut, which are estimated to make up 50% of all the cells in our body and can weigh up to 2kgs in an average adult.
These bacteria feed off the food we consume and are essential in assisting our body to break down compounds into their simplest forms in order for the nutrients in our food to be absorbed. They are also responsible for producing and synthesizing many of our hormones as well as continually developing our immune systems. Yet these bacteria can be quite sensitive to our diet, our environment and any other imbalances within our body.
The Gut-Brain Axis
We all know our mood is affected when we don’t feel our best. Often a headache or stomachache can make us feel grumpy, irritable and lethargic. So it’s easy to imagine how imbalances within our gut can trigger and affect our mood on a much larger scale.
Developing research has found a significant connection between our brain and our gut, through the gut-brain axis. This axis or pathway facilitates communication between our microbiome and our brain via our immune system, the vagus nerve (connecting our brain to the rest of our body), bacteria interaction and production of neurotransmitters or hormones within our gut.
Serotonin and dopamine are examples of hormones produced in the gut, which send signals to the brain inducing feelings of happiness, reward and motivation. The bacterial strains Candida, Streptococcus, Escherichia and Enterococcus produce the majority of serotonin within our gastrointestinal tract and dopamine is produced by Bacillus bacteria also within the gut.
As a result, when gut function is compromised, the production of such feel-good hormones is also affected, with dysfunction in signalling and transmission linked to symptoms of anxiety, depression and low motivation.
Research has found that stress can also alter our microbiome in many ways, with stress responses in the body triggering changes in gut movement, enzymes and gastric juices. With such altered conditions within the gut, bacteria cannot adhere, function or replicate as usual.
As a result, bacteria pass through our gastrointestinal system and out of our body. So we lose the benefits of healthy gut bacteria and the associated production of feel-good hormones, nutritional extraction and any built-up immunity.
It’s a little like the chicken and the egg scenario- stress causes us to lose our good bacteria which in turn affects our ability to produce feel-good hormones resulting in more stress, triggering the loss of more bacteria and perpetuating the cycle.
Pre & Probiotics
So how can we improve our gut bacteria, break this negative cycle and benefit from a diverse and healthy gut microbiome?
In 1930 Japanese microbiologist Dr Minoru Shirota isolated the Lactobacillus casei strain Shirota and identified its function in improving the digestive system, leading to the development of the probiotic fermented drink Yakult in 1935.
Probiotic products such as Yakult contain live bacteria which, when consumed continue to live and grow in our gut, assisting the colonization and diversification of our gut bacteria as well as reducing the growth of any harmful bacteria within our gut. Probiotics can also be found in other fermented dairy foods such as yoghurt and kefir as well as fermented vegetables; kimchi and sauerkraut and fermented soy including miso, tempeh and natto. Or nowadays you can simply take a probiotic supplement.
Our gut also benefits from prebiotics, or non-digestible carbohydrate molecules from our food, which again feed and nourish our gut microbiome. Prebiotic foods also bulk out bad bacteria and assist with calcium metabolization, glycemic response and bowel transit time. Many plant-based whole foods can be considered prebiotic, with many vegetables high in complex carbohydrates, starches and fibre ranking highly on the prebiotic scale.
Good Mood Food
When choosing foods to improve gut health and promote good bacteria within our bodies there are a few simple rules to follow. By simply focusing on a diverse range of plant-based foods of the highest quality, in their most holistic form (the less processed the better), we can easily pack our diet full of nutritional diversity, high in both pre and probiotic properties.
In also identifying, reducing and/or avoiding any personal food triggers we can reduce digestive discomfort and continue to curate a healthy microbiome. Common food triggers are dairy, wheat and sugar, yet it is important to remember that each of these food groups plays an essential role in our diet and eliminating any food groups should be done with professional guidance and supervision.
If you are interested in better understanding your gut health, try keeping a food and symptom diary for a week and look for any patterns or connections between foods and digestive symptoms occurring shortly after consumption.
Overall modern science has begun (and is continuing) to discover the intrinsic connection between mind and body, with the health of our gut impacting not only our ability to absorb and process nutrients but also our production of feel-good hormones, affecting our mood, stress levels and mental health.