Over the past ten years there has been a dramatic increase of research into the relationship between our gut microbiome and our mental health. Many interesting facts are emerging from this new area called the gut-brain axis, increasingly linking the health of our gut - IBS symptoms and our mood.
Last year researchers from 5 leading UK universities (1) concluded that patients were considerably more likely to be diagnosed with depression before a diagnosis of an inflammatory gut condition. So, what’s happening in our gut that is affecting our mood.
Trillions of bacteria live in our gastrointestinal tract and play an important role in digestion, immunity, and the production of nutrients. Each of us has a unique pattern of bacteria from the thousands of different species that make up this population. These bacteria are crucial to many aspects of our health and wellbeing as well as to the health of our gut.
Significant stress, continuous inflammation from excessive sugar consumption and the use of antibiotics depletes beneficial bacteria in the gut allowing an opportunity for less favourable species to gain a foothold. It is this combination of events that can lead to alterations in gut hormones and neurotransmitters affecting the way we feel.
Symptoms of low mood, anxiety and depression may not typically be about feeling sad, they can include a loss of interest in previously enjoyed activities, changes in appetite, sleep patterns, an increase in fatigue and difficulty concentrating.
The gut brain microbiome
The gut has often been referred to as our second brain as it literally operates its own local nervous system, reacting to external signals. We feel butterflies when we are nervous and experience tension in our gut when we feel fear, these are all expressions of communication between our brain and our gut. Researchers are learning that this pathway of nerve messages is bi-directional and connected both positively and negatively to our gut bacteria.
Our feelings of happiness come from chemical neurotransmitters called serotonin, norepinephrine, dopamine and GABA, controlling sensations of pleasure, mood and anxiety. When the levels of these hormones reduce, we feel low in mood or depressed.
Most of our serotonin is found in our gut and levels of serotonin are dependent upon both a good diversity of gut bacteria (2) and adequate levels of protein in our diet. Specifically, to produce serotonin, we need to eat foods containing an essential substance called tryptophan, found in foods such as:
Chicken, turkey, nuts, seeds, tofu, eggs, and salmon
Ensuring these foods are regularly in your diet will help to restore levels of the hormone serotonin.
Additionally, probiotic bacteria taken over a four-week period have been shown to have a direct correlation to the increase of the hormone serotonin (3), along with fewer negative thoughts connected with low mood (4). These beneficial bacterial species include:
Bifidobacterium and Lactobacillus
The extent of the diversity in our gut bacteria is directly related to the range of foods we eat that feed these bacteria.
There are certain foods that feed our gut bacteria.
The importance of fibre in our diet
The fibre we eat acts to feed beneficial gut bacteria. Bacteria ferment and convert fibre into short chain fatty acids which are crucial for the maintenance of our intestinal lining. A healthy gut lining ensures an environment that can maintain normal production of serotonin and digestion of other nutrients essential for our mental health. Short chain fatty acids work as a source of energy in the process of gut cell repair.
Groups of foods that contain the fibre that supports the gut microbiome and cellular repair, include:
Inulin: inulin is found in artichokes, garlic, leeks, onions, and asparagus
Fructooligosaccharides (FOS): FOS are found in many fruits and vegetables, including bananas, onions, garlic and asparagus
Resistant starches: are found in rice, beans, green bananas, legumes and potatoes that have been cooked and then cooled
Pectin: good sources of pectin include apples, apricots, carrots, oranges is worth also remembering that fermented foods also help us increase our gut microbiome diversity. Incorporating kimchi, sauerkraut, and kefir regularly into our diet has been shown to have a positive effect on our microbiome.
Stress and our gut brian response
It’s not just our diet that affects our gut microbiota. More recent research is linking very low levels of serotonin in our gut directly to the level of stress or chronic inflammation we experience, which in turn, increases our sensitivity to anxiety (5).
Our body reacts to all stressors in broadly the same way by producing hormones, most notably cortisol, and a cascade of other cells. Stress comes from our perception of fear of what is, or what we believe is happening, or going to happen to us, physically or emotionally. Separately, internal stressors are generally caused by long term chronic inflammation. Both these situations result in the body producing cortisol, and long term circulating cortisol causes oxidative stress known as chronic inflammation (6). Internal stressors come from ongoing conditions of:
Long term disrupted sleep or regular sleep loss
Blood sugar imbalances (see blood sugar blog) and increased insulin
Eating inflammatory foods, particularly added sugar and refined carbohydrates, processed meats, and artificial sugars
Allergies and food intolerances
Knowing that these circumstances contribute to chronic inflammation allows us the means and motivation to take action to address these areas and regain some control in our lives.
Some easy to accommodate helpful tips to lower inflammatory stress, include:
Build in movement during your day
If you’re working from home, take a quick walk in the fresh air in the morning before work and after lunch. Any kind of movement, even from walking short distances will help you refocus, take in more oxygen, and will lower stress levels. Turn off your phone so you can fully detach from thinking about work problems.
Disconnect from your workday
Being able to fully disconnect from work is important in lowering stress. Establish some boundaries where you can end your working day and transition into your own time. It’s worth taking a few minutes of quiet time to detach from your work thoughts and switch your mind to the present.
Healthy food and blood sugar management
Revisit our article on blood sugar management; high insulin levels are associated to increased inflammation and internal stress. Try to eat protein with each meal and reduce your level of processed carbohydrates. Keeping hydrated is helpful as becoming mildly dehydrated can increase internal stress.
Work to improve your sleep
This is the biggest single thing you can do to reduce stress. Plot how much sleep you get and how you feel the following day. If you get less than 8 hours sleep build a new routine that allows you to achieve this minimum amount of uninterrupted sleep. To improve sleep quality, check your room temperature, mattress, and pillows to ensure they still provide adequate support. This is an area of investment that returns dividends on your health.
If there are any areas mentioned in this article you would like to discuss in more detail, please contact Henley Nutrition, 07831 120423, www.henleynutrition.co.uk
1. Blackwell J. et.al, (2020) Depression in individuals who subsequently develop inflammatory bowel disease: a population-based nested case-control study
2. Yano J, M. et.al (2015) Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis
3. Desbonnet, L. et.al. The probiotic Bifidobacteria infantis: An assessment of potential antidepressant properties in the rat
4. Steenbergen, L. et.al. A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood
5. Yong-Ku, K. Jeon, Sang Won, (2018). Neuroinflammation and the Immune-Kynurenine Pathway in Anxiety Disorders
6. O’Donovan, A. et.al. Good stress, bad stress and oxidative stress: insights from anticipatory cortisol reactivity