"I have a knot in my stomach"
It's not just a figure of speech. We all know that feeling, that uneasy feeling in your stomach that comes with anxiety or nervousness. And we hope that it remains just a feeling and that the urge to quickly go to the toilet doesn't suddenly arise. Accelerated intestinal transit and increased stool frequency are relatively common in tense situations (e.g. abdominal pain and diarrhea before an exam or other important appointment).
Gut & Brain
Our gut (or our gut microbiome) is closely linked to the brain via the microbiota-gut-brain axis. It is therefore no wonder that mental stress is often accompanied by digestive disorders. The gut and brain communicate through the gut microbiome, as well as through the enteric, autonomic and central nervous systems and influence each other. Among other things, neurotransmitters (e.g. GABA), short-chain fatty acids, tryptophan metabolites of the gut microbiome and hormones play a crucial role.
Anxiety leads to a greater sensitivity to pain in the intestines due to the release of stress hormones. Intestinal activity increases, inflammatory processes in the gut increase, and the composition of the gut microbiome changes. Dysbiosis, in turn, has a negative impact on the functioning of the gut-brain axis and affects our mood and emotions.
A vicious circle arises: Anxiety creates gut problems and gut problems create anxiety.
Conversely, a well-balanced gut microbiome supports our mental health (1, 2, 3).
So it makes sense to take care of both equally!
Fear & Anxiety
Fear and anxiety are part of our lives and are both emotional reactions that, in very simple terms, differ in their triggers and intensity:
FEAR is a natural response to a real or perceived immediate threat in which there is no time for thought. These are situations in which increased vigilance is required in order to take protective measures or mobilize our forces. Fear is usually temporary and tied to specific triggers. It is a survival mechanism (fight-or-flight or freeze response) that we use to save our lives now. Only then do we process what happened and learn which situations we should avoid in the future.
ANXIETY, on the other hand, is a more general feeling of unease, worry, or concern about the future.
It often occurs at an inopportune moment, is disproportionate to the actual threat, and can last for a long period of time even when there is no immediate danger. Symptoms can include tension, restlessness, difficulty concentrating, irritability, muscle pain and sleep disorders.
A healthy level of fear and anxiety is subjective and varies greatly from person to person. In general, they serve as protective mechanisms that help individuals respond to threats and overcome challenging situations. When anxiety becomes excessive, persistent, or interferes with daily functioning, it may indicate an anxiety disorder or another mental health problem. Pathological fear not only puts a strain on health, it paralyzes the ability to act and subsequently also affects the social and economic structure of the person affected.
With an incidence of 3-25%, anxiety disorders are among the most common psychiatric illnesses worldwide. In addition, over 1/3 of all people experience anxiety symptoms during their lifetime (4, 5, 6, 7).
There are various anxiety disorders (e.g. generalized anxiety disorder, panic attacks, social anxiety disorder, phobias, post-traumatic stress disorder) each with different symptoms (e.g. nausea, vomiting/diarrhea, shortness of breath, dizziness, sweating, racing heart, chest tightness, etc.). What they all have in common is the feeling of helplessness, the feeling of losing control over fear. Both genetic and environmental factors (e.g. stress, traumatic experiences) are cited as risk factors for the development of anxiety disorders. But physical characteristics, such as problems with the thyroid or heart disease, as well as substance abuse can also be involved in the development of anxiety disorders.
Anxiety disorders are treated with psychotherapy, behavioral therapy and/or medication (8).
And the gut microbiome? Can it also contribute to this?
People with anxiety disorders have been shown to have altered gut microbiomes compared to people without anxiety disorders (1, 2, 8).
The question is, which came first?
Has fear thrown the gut microbiome out of balance or has an unbalanced gut microbiome led to increased anxiety?
The majority of the studies carried out rely on animal models. For example, a study on mice clearly found a connection between social anxiety and the gut microbiome.
The mice studied either received gut bacteria and other microorganisms from people with social anxiety disorders or from healthy people. Mice that received transplants from people with social anxiety disorder showed less social interaction on subsequent days, which is typical of social anxiety. They also had lower levels of oxytocin. These results, and those of other studies, suggest that dysbiosis has a causal relationship with the development of anxiety (2, 3, 9).
The data available in humans is still limited, but there is clear evidence that the gut microbiome also affects the central nervous system in humans, influences our behavior and therefore also plays an important role in mental illnesses such as anxiety disorders or depression.
Since the above-mentioned treatment approaches for anxiety disorders (psychotherapy and medication) are not always successful, there is great interest in other options. The gut microbiome and its influence on mental health and therefore also anxiety is being studied more and more. Individual probiotic strains and synbiotics have already been shown to improve symptoms. “Psychobiotics” are increasingly being talked about. Including the gut microbiome in therapy seems to be a promising strategy. A review that considered 21 studies showed that treating anxiety symptoms by regulating the gut microbiome was positive in more than 50% of the included studies (1, 2, 3, 7, 8, 10).
Practical tip: Sport (or just a brisk walk) in nature
On the one hand, this brings exercise into everyday life, and on the other hand, physical activity and fresh air have a positive effect on the quality of sleep. Consciously take time for yourself, concentrate on nature with its sounds, smells, weather conditions, etc., pay attention to your own breathing and try to become calmer and relax inside while moving.
Exercise, restful sleep, relaxation exercises and more mindfulness have a positive effect on the gut-brain axis from both sides (gut - brain & brain - gut) (2).
Anxiety doesn't manifest itself from one day to the next ...
... it develops. And, while manifest anxiety disorders clearly require medical care, there are a few things we can do prophylactically to get there. Changes and upheavals are part of our lives. They shake our stability, can unsettle and create anxiety. There are a lot of things we don't have control over and we can't influence. But it is up to us to train ourselves in everyday life to cope better with uncertainty so that we can be better prepared when we have to deal with anxiety ... (6).
We can dare, for example,
• to regularly leave our comfort zone and try something completely new, completely spontaneously, not knowing what is coming …
• consume news only once a day for a limited time.
• to allow social contacts to take place more in real life again, instead of mainly online.
• learn breathing techniques that help us calm down and think more clearly in anxious moments.
• paying attention to our gut feeling and proactively doing something to make our gut “feel good”.
A balanced gut microbiome would be the first step ;-)
Would you like to know more about your gut microbiome and how you can support it? Then get in touch!
References
(1) Karolina Krupa-Kotara et al. (2023): The Role of Microbiota Pattern in Anxiety and Stress Disorders – A Review of the State of Knowledge, in: Psych 5(3):602-618.
(2) Stefano Bibbò et al. (2022): Gut microbiota in anxiety and depression: Pathogenesis and therapeutics, in: Frontiers in Gastroenterology 1:1019578.
(3) Ruo-Gu Xiong et al. (2023): The Role of Gut Microbiota in Anxiety, Depression, and Other Mental Disorders as Well as the Protective Effects of Dietary Components, in: Nutrients 15:3258.
(4) National Institute of Mental Health https://www.nimh.nih.gov/health/topics/anxiety-disorders
(5) Lucie Daniel-Watanabe, Paul C. Fletcher (2022): Are Fear and Anxiety Truly Distinct?, in: Biological Psychatry Global Open Science 2(4):341-349.
(6) Judson Brewer (2021): Unwinding Anxiety: New Science Shows How to Break the Cylces of Worry and Fear to Heal your Mind, Avery.
(7) Beibei Yang et al. (2019): Effects of regulating intestinal microbiota on anxiety symptoms: A systematic review, in: General Psychiatry 32:e100056.
(8) Zaiquan Dong et al. (2021): Gut Microbiome: A Potential Indicator for Differential Diagnosis of Major Depressive Disorder and General Anxiety Disorder, in: Frontiers in Psychiatry 12:651536.
(9) Nathaniel L. Ritz et al. (2023): Social anxiety disorder-associated gut microbiota increases social fear, in: PNAS 121(1)e2308706120.
(10) Katerina V.-A. Johnson (2019): Gut microbiome composition and diversity are related to human personality traits, in: Human Microbiome Journal 15 https://doi.org/10.1016/j.humic.2019.100069.
