Some might say that it all starts in the gut. Some people don’t even think there is a correlation between mental health and gut health.
Have you ever had those days when you feel bloated, gasy, constipated and super irritable, uncomfortable, introverted and just want be by yourself? Well, there must be something about the term “the gut is your second brain”.
If you look closer to the structure and appearance of the IT (intestinal tract) it indeed does look like a brain. So how come that they say that the gut is linked to your brain?
The healthy gut hosts trillions of microbes, an ecosystem which can vary from individual to individual. These little critters outnumber the human cells by 10:1.
The microbes in your gut not only help to digest and absorb nutrients but also partner up with the nervous system of your GI tract (ENS) and send out signals to the brain and throughout the body.
Factors that contribute to your gut microbiome include:
Infant feeding method
A variety of ‘good’ over ‘bad’ bacteria is beneficial to health. Whereas the opposite can lead to health issues, like IBS, SIBO, Candidiasis.
Diet is one of the key factors that can substantially affect microbiota composition. You can feed the good guys or the bad guys via the food you ingest. For example, a diet full of sugar (Candida LOVES sugar), processed foods, pesticides, antibiotics, and acidic foods can lead to certain bacterial overgrowth, cause inflammation or gut dysbiosis, and in worst case, auto-immune reactions.
To contrast, a diet full of vibrant, whole, enzymatic and nutrient rich foods can add and nurture the good bacteria that contribute to your immune system and healthy brain function.
More research on the microbiota–gut–brain axis has emerged (7,8,9).
Certain probiotic strains can modulate various aspects of the microbiome‐gut‐brain axis (10). A growing body of evidence indicates that microbiota have a role in the normal regulation of behaviour and brain chemistry that are relevant to mood and anxiety.
Did you know that most of your serotonin is produced in your gut?
Enteric Nervous System
As mentioned earlier the gut has a nervous system, which is called the Enteric Nervous system (ENS). This Nervous System is part of the Autonomic Nervous System (ANS), defined as sympathetic (fight or flight), parasympathetic (rest and digest) and enteric nervous system (gut-brain).
However the ENS works independently from the CNS, meaning that it has the ability to control gastrointestinal behaviour independently of input from brain or spinal cord (1,2,3.) In contrast, it can send signals from the gut to the brain (2,4).
The Vagus Nerve is the main conduit between the CNS and the ENS. It runs from the brain stem down to the abdominal, allowing signals to run freely. Studies have shown that several conditions from the CNS can manifest in the ENS and reversed. For example, Parkinson’s Disease or Alzheimer Disease have enteric consequences or IBS, Candida can effect brain function (fogginess, lack of concentration etc).
The gut is also linked to your immune system. Your gut wall is lined with epithelial cells, a mucosal lining. This lining is very important in protecting the internal milieu from pathogens and hostile microbes, but is also responsible for absorption and waste secretion. Increased permeability, caused by pro-inflammatory components, stress and pathogens can disrupt mucosal lining and therefore decrease regulation and weaken the immune system, in worst case cause an autoimmune reaction (i.e. Celiac Disease, Lactose Intolerance).
The host provides food and shelter for the little critters and in return they support the intestinal immune system by fighting pathogens, harmful bacteria, viruses and fungi.
It’s important to maintain a healthy microbiome by providing prebiotics (high-fibre foods) and probiotics (live beneficial bacteria).
So how can we support the gut and healthy brain function?
How to support a healthy gut
1. Eat healthy fats.
The brain and nervous system are totally dependent on a family of fats.
Non-essential fatty acids (N-EFAs)
Saturated and monounsaturated fats, (SFA and MUFA)
Essential Fatty Acids (EFAs)
Omega 3, EPA and DHA
Omega 6, GLA and AA
The N-EFAs can be made in the body, but the EFAs have to be obtained through diet.
Sources (11) are
2. Avoid toxins
Exposure to toxins, pollution, radiation, heavy metals can cause oxidation and inflammation and impact gut and brain function. Antioxidants like Glutathione, vitamins A, C and E; beta-carotene; bioflavonoids, QoQ10, selenium; and zinc can help to protect us from free radical damage.
3. Stabilize blood sugar
Blood sugar fluctuation can cause irritation, anxiety and depression. The body is constantly balancing blood sugar and slight fluctuations are normal. But when there is an excessive sugar intake the liver and pancreas can’t keep up with Insulin production to down regulate blood sugar and health issues can develop (i.e. diabetes, insulin resistance).
Normal blood sugar levels are sustained through a combination of eating a balanced, low-processed diet, getting regular exercise and managing the body’s most important hormones in other ways (such as getting enough sleep and reducing stress)
4. Stay emotionally healthy.
Psychological problems can change our relationship to our body through the lack of nourishment or misusing mind-altering substances leading to chemical imbalance in the brain. Depression, anxiety and memory problems are also linked to what we eat (12).
Stress is a major contributor to inflammation, gut dysbiosis, endocrine disruption, immune dysregulation.
Practicing meditation can help activate the parasympathetic nervous system (rest and digest) and reduce stress, anxiety and depression.
Spending time in nature can quieting the mind and help calm the nervous system. A general feeling of well-being and higher self-esteem has been reported by individuals in a study from the University of Essex in 2007.
5. Exercise regularly.
Regular Exercise has also been shown to reduce inflammation via several different processes (inflammation, cytokines, toll-like receptors, adipose tissue and via the vagal tone), which can contribute to better health outcomes in people suffering from mood disorders (13).
6. Eat fermented veggies.
Fermented vegetables are loaded with good bacteria (probiotics) that help with your digestive system, strengthen your immune system and contribute to healthy brain function.
Prebiotics are non-digestible parts of foods that go through the small intestine undigested and is fermented when it reaches the large colon, where it feeds the good bacteria.
So its important to bring in new good bacteria but also feed them and keep them healthy.
To summarize this up there are several ways to keep your gut and brain healthy.
But most importantly, we need to bring more awareness into our food choices and body's symptoms. Our body is constantly communicating with us and if we do not pay attention, deny or neglect these symptoms we are set up for disaster. So next time you feel irritable, uncomfortable or experience anxiety make sure you giving your body what it needs.
1. Gershon MD. The Second Brain. Harper Collins; 1998. [Google Scholar]
2. Furness JB, Callaghan BP, Rivera LR, Cho HJ. The enteric nervous system and gastrointestinal innervation: integrated local and central control. Adv Exp Med Biol. 2014;817:39–71. [PubMed] [Google Scholar]
6. Rao M and Gershon MD.The bowel and beyond: the enteric nervous system in neurological disorders. Nat Rev Gastroenterol Hepatol. 2016 Sep; 13(9): 517–528. [PubMed]
7. Rhee, S. H., Pothoulakis, C. & Mayer, E. A. Principles and clinical implications of the brain–gut–enteric microbiota axis. Nature Rev. Gastroenterol. Hepatol. 6, 306–314 (2009). One of the first papers to formalize the concept of a microbiota–gut–brain axis.
8. Cryan, J. F. & O'Mahony, S. M. The microbiome–gut–brain axis: from bowel to behavior. Neurogastroenterol. Motil. 23, 187–192 (2011).
9. Collins, S. M. & Bercik, P. The relationship between intestinal microbiota and the central nervous system in normal gastrointestinal function and disease. Gastroenterology 136, 2003–2014 (2009).
11. Holford P. Optimum Nutrition for the mind. Great Britain, 2007,p. 39
12. Holford P. Optimum Nutrition for the mind. Great Britain, 2007,p. 424-425