Gut health and mental health: microbiome and nutrition
“Just a few years ago, it would have been difficult to imagine that brain disorders actually start in the gut. [...] The chemical compounds secreted by microbiota can affect mood and [...] mood itself can also affect microbiota.”
Erica and Justin Sonnenberg
Microbiology and Immunology Researchers1
The phenomenon of neuro-nutrition is quickly developing and can be backed up by sound, scientific data stipulating that there is indeed a direct gut-brain connection.
Early studies on mice helped identify the link between the gut microbiome and the brain. Several studies focus on transferring gut microbiota (living microorganisms in the gut microbiome) from one mouse to another and then observing any behavioral changes that occur. For example, if you transfer gut microbiota from a more adventurous mouse into one that is more passive, the latter quickly develops more dynamic abilities. The same happened when researchers introduced gut microbiota from a calm mouse into an aggressive mouse and vice versa; the calm mouse became more aggressive and the aggressive mouse became more relaxed2. These findings reinforced the idea that families of gut bacteria have an influence on mental health.
Literature refers to the gut as a “second brain” as it alone contains 200 to 500 million neurons, roughly equivalent to the number of neurons found in a small house pet.3 The brain “communicates” with the gut using neurons found in the autonomic nervous system and by secreting hormones that follow a precise path from the hypothalamus (brain structure) in order to reach the adrenal glands, situated, as their name indicates, above the kidneys. In turn, the gut sends messages to the brain through metabolites and chemical transmitters that use the vagus nerve or the bloodstream to reach their destination. This communication between the brain and the gut can be described as bidirectional.
Gut flora imbalance: impacts on physical and mental health
Any disturbance of gut microbiome that compromises the quantity and variety of bacteria in the digestive tract can have an impact on certain central nervous system disorders.
The simplest and most clinically observed phenomenon of this gut-brain relationship is the impact that stress has on gut motility, or in other words, on digestion speed and bowel movements. During periods of stress, our bodies react in different ways and it is not unusual, for example, to experience bouts of diarrhea. When subjected to this type of attack, bacteria can sense changes to their environment. Extended periods of stress and frequent diarrhea can have an effect on gut microbiome composition over the long term5.
Suffering from unbalanced gut flora has also been associated with a higher perceived level of pain, an increase in depressive behavior and stress, hypersensitive digestion, changes to the immune system and an increase in gut motility related to changes in the endemic barrier7.
It has also been established that the ratio of the most common families of bacteria influences not only digestive health but memory, behavior, stress, depression, and anxiety by regulating neurotransmitter activity; small chemical messengers that ensure good communication between each cell in the brain and each nervous cell elsewhere in the body8,9.
How to improve gut health
Taking care of your gut microbiome is a key factor in achieving optimal physical and mental health. Avoiding disruptions and prioritizing the adoption of healthy lifestyle habits allows the right families of bacteria to grow in a favorable environment. On top of incorporating daily physical exercise, it is proven that incorporating some nutritional changes minimizes depressed thoughts and anxiety triggers, helping to sustain a diversified gut microbiome and allowing the growth of “good” bacteria.
1. Eat fiber: Eat 2–3 portions of thoroughly washed fruit every day, mix in 2 cups of colorful vegetables at lunch and supper, incorporate nuts and grains daily and choose products made with whole grains;
2. Rethink proteins: A few times a week, replace animal proteins with fatty fish (sardines, mackerel, herring, trout, salmon) and vegetable proteins (legumes, edamame beans, tofu, tempeh, nuts, and seeds);
3. Limit saturated fats: As often as possible, replace processed meats with eggs, tuna or salmon mixtures, chicken or shrimp and eat fewer servings of red meat;
4. Integrate fermented foods on a weekly basis: Learn how to cook with miso, tempeh, kimchi, sauerkraut, etc.;
5. Take probiotics10: Choose a well-known and scientifically proven probiotic when your body needs a little extra pick-me-up (back-to-school, cold and flu season, holiday season, year-end, when traveling or when taking antibiotics), in order to strengthen your immune system and maintain the quantity and diversity of “good” bacteria in your digestive tract.
Bio-K+ probiotics are the perfect balance between a fermented product and a 100% probiotic product. The 3 bacterial strains found in Bio-K+ products work synergistically, meaning that they are more effective together than apart. Of human origin, they are genetically much easier for our bodies to recognize. These probiotic bacteria stimulate the growth of other “good” families of bacteria in the digestive tract, allowing gut microbiome to properly perform its functions. Whether you prefer enterosoluble capsules or drinkables, Bio-K+ ensures the quality and efficiency of its bacterial strains and guarantees bacterial concentration upon consumption.
When it comes to neuro-nutrition, the saying “you are what you eat” couldn’t be more accurate. We need good fats, vitamins, specific minerals and complete proteins for neurotransmitters to synthesize. We must do what it takes to maintain the integrity of our gut microbiome, as it alone greatly influences whether or not we are in good physical and mental health11.
Do you have any other questions concerning the health of your gut microbiome or how to build your immune system? Ask them in the comments below!
- Sonnenburg, E. et Sonnenburg, J. (2016). L’étonnant pouvoir du microbiote, Montréal, Éditions Édito, p. 145-146.
- Bercik P et autres, « The intestinal microbiota affects central levels of brain-derived neurotropic factor and behavior in mice », Gastroenterology, 2011, vol. 141, no 2, p. 599-609.
- Schmidt, C. Mental Health: thinking from the gut. Nature. 2015; 518: S12-15.
- Bercik P, Denou E, Collins J, et al. The intestinal microbiota affects central levels of brain-derived neurotropic factor and behavior in mice. Gastroenterology. 2011; 141: 599-609. (Cité dans Lagacé, p. 186)
- Desautels-Marissal, M. (2016). Mille milliards d’amies: comprendre et nourrir son microbiome. Montréal, Éditions Cardinal, p. 50.
- Ici Radio-Canada télé. Microbiote, nouvel organe. Découverte. Saison 28, épisode 3, 27 septembre 2015.
- O’Mahony SM, Marchesi JR, Scully P, et al. Early life stress alters behavior, immunity, and microbiota in rats: implications for irritable bowel syndrome
- Carabotti M. Scirocco A, Maselli MA, et al. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol. 2015; 28: 203-209.
- Rhee SH, Pothoulakis C, Mayer EA. Principles and clinical implications of the brain-gut-enteric microbiota axis. Nat Rev Gastroenterol Hepatol. 2009;6(5):306–14.
- Ann Gen Psychiatry.2017 Feb 20;16:14. doi: 10.1186/s12991-017-0138-2. The effects of probiotics on depressive symptoms in humans: a systematic review, eCollection 2017.
- Collins SM, SuretteM, Bercik The interplay between the intestinal microbiota and the brain. Nat Rev Microbiol. 2012;10(11):735–42. pmid:23000955