The communication between the gut and the brain forms an intimate connection that defines each individual as themselves. The gut produces signals and hormones that are highly active in the brain and help us choose which decisions to make. These signals and hormones can promote anxiety, happiness, sadness, depression, and many other feelings that help us to navigate the world. The gut helps to provide feedback to the brain via signals/hormones to help the brain make decisions that will benefit our gut microbiota. And the brain chooses whether the body should comply with these signals or choose an alternative path.
The brain also produces signals and hormones that are highly active in the gut and help the gut digest foods during optimal times throughout the day. For example, the brain can promote a relaxed state in the gut (the parasympathetic rest and digest response), or a stressed state in the gut (the sympathetic fight, flight, or freeze response). Overall, these two different responses allow the gut to digest foods when we are in a calm and relaxed state or hold off on digestion when we need to use energy for other activities that take precedence over digestion at any given time.
Have you ever heard someone say?...
“Trust your gut”
“I have a gut feeling”
“My gut is telling me…”
What they are probably referring to is how the organisms in the gut microbiome are producing hormones, like dopamine, that give you the sensation of a feeling. These sensations are created for a reason. These sensations are created to help provide us with feedback and guide us to make the best decision at any given moment. But what happens if you have irregular occurrences in the gut, like dysbiosis, food poisoning, constipation, etc. Then are the signals from your gut giving you feedback to avoid harm out of fear, more than to promote wellness out of prospect?
When the gut is not functioning regularly to promote wellness, this can affect your feelings and how you act. For example, Bifidobacterium spp. are a type of bacteria in the gut that reduces anxiety. These organisms produce signals that let the brain know everything is okay, “it is a good time to rest and digest”. Conversely, the organism Campylobacter jejuni are organisms that promote anxiety. These organisms produce signals that let the brain know that it is time to act, “it is time to either take flight, freeze, or fight!” These two organisms are examples of how the gut and organisms in the gut can affect behavior. Now think about the fact that there are anywhere from hundreds to thousands of different species of organisms that live in the gut microbiome alone!
The Supervisor in Charge, The Brain
If the gut is the second brain, then what does the first brain do?
Signals gut motility/promotes healthy digestion
Begins the digestive process in the gut
Stimulates hunger and fullness cues
Relays feedback to stimulate sympathetic/parasympathetic states in the gut
All of the processes above are basically saying that the brain is the control center of the gut. The brain is like the supervisor at a job. The brain tells the gut what to do and then the gut takes that information, processes it, and does it. For example, you walk in the kitchen, smell fresh baked bread, see the golden crust, and your brain says, “that looks good, lets signal the gut that it is time to eat.” Or you are on the move and stressed out. Your brain will signal your gut, “no time to eat now, better wait until later when we have time to relax and enjoy our food.” Both examples display how the brain signals the gut to promote either the sympathetic fight, flight, or freeze response or the parasympathetic rest and digest response.
The Gut Brain Axis
Now you know a little about how the brain interacts with the gut, and how the gut interacts with the brain. But what hasn’t been discussed is how the ecosystem of the gut-brain axis works. In this ecosystem the brain is dependent on the gut and the gut is dependent on the brain. This means that when the brain is healthy and functioning optimally, the gut can also remain healthy and function optimally, and vice versa. But if either the brain or the gut becomes compromised, then the whole ecosystem becomes compromised. For example, someone with a neurological disease like Parkinson’s, Autism, Multiple Sclerosis, or Alzheimer’s almost always has digestive issues in the gut. This is because the signals that the brain is sending to the gut are not providing the best information for the gut to remain healthy and function optimally.
Likewise, we can see neurological issues occur more frequently when there are issues in the gut like Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD), Small Intestinal Bacterial Overgrowth (SIBO), or a general dysbiosis. Some of the issues we commonly see are brain fog, migraines/headaches, mental fatigue, and an increased risk for neurological diseases. This is because if IBS, IBD, SIBO, or dysbiosis is present in the gut, then the gut may only be functioning at only 80%, 50%, or. Even 25% or lower . This means that the gut is not creating the optimal levels of signaling molecules/neurotransmitters needed in the brain. Also, if the gut is out of balance, then some of the organisms in the gut that affect our behavior, like Bifidobacterium spp., Campylobacter jejuni, Lactobacillus rhamnnosus, may be out of balance. So, the brain ‘supervisor’ may be providing all of the signals needed to get the job done, but the gut does not have all of the necessary organisms/materials needed to complete the job.
But Wait, there is Good News!
Well, I’ve got some good news, and I’ve got some bad news. The bad news is that an impaired brain negatively affects the gut, and an impaired gut negatively affects the brain. The good news is that there are steps you can take to address imbalances and promote health in both the gut and the brain. For instance, probiotic therapy has been used for many neurological conditions including depression, anxiety, Autism, Alzheimer’s, and many others. There is even a specific term for these types of probiotics. The term ‘psychobiotics’ is a term used to refer to probiotics that have a positive effect on nervous system function. But probiotics are not only used for serious neurological conditions, they are also used to help improve mental clarity, mood, memory, thinking, reactivity, and emotional wellness.
More Good News!
Changes to the diet that promote the growth of beneficial organisms in the gut help to promote both brain and gut health. Some of the organisms mentioned above, like Bifidobacterium spp., Lactobacillus rhamnnosus and Campylobacter jejuni can be modified with changes in the diet. For example, including foods that are high in prebiotic fiber can help the beneficial organisms, like Bifidobacterium spp. and Lactobacillus rhamnnosus grow. Not only do prebiotics help beneficial organisms grow, they also reduce the growth of organisms that can cause health and behavioral issues, like Campylobacter jejuni. Some foods high in prebiotics include root vegetables, dandelion greens, garlic, asparagus, bananas, and many other fruits and vegetables.
“But What if Prebiotic Foods Don’t Help Me?”
For some individuals, including more foods high in prebiotic fiber may be enough for them to harvest a healthy gut brain connection, but for others it just might not be enough. The amazing ecosystem that includes the gut brain connection can be difficult to navigate sometimes. Because the gut and the brain are in close communication with each other, they work as a team and thus if one member of the team does not do their job it is hard for the other member of the team to do theirs. The good news is that prebiotic fiber is only one potential treatment for obtaining optimal gut and brain health. There are many other treatments that can be beneficial and have been proven to be beneficial in evidence based research.
Therapies & Treatments for Gut Brain Health
Some treatments for brain, gut and mental health include
Cognitive behavioral therapy (CBT)- this treatment has been shown to be effective and strongly recommended for treating IBS. CBT works by changing maladaptive thoughts in a therapeutic manner.
Hypnosis- has been shown to be effective and strongly recommended for treating IBS. Hypnosis is a great therapy for the gut and the brain because it offers symptomatic, physiological and psychological benefits.
Eye movement desensitization reprocessing (EMDR)- this type of therapy can help reduce IBS associated with anxiety, depression, trauma, PTSD, and panic disorders. “EMDR therapy, rather than focusing on changing the emotions, thoughts, or behaviors resulting from the distressing issue, allows the brain to resume its natural healing process.”
Treatments for gut and brain health
Prebiotics- these beneficial fibers have been shown to balance out the gut microbiome by promoting the growth of healthy gut organisms and decreasing the growth of organisms not beneficial for health. These fibers promote gut and brain health as the healthy organisms promoted produce neurotransmitters for brain health and short chain fatty acids for gut health.
Psychobiotics- These are probiotics that have a positive effect on nervous system function. Psychobiotics have been shown to improve brain health because they promote the production of neurotransmitters and mood regulating hormones in the gut.
Anthocyanins- are blue, red, or purple pigments found in plant foods. Foods like blueberries, eggplants, beats, cherries, and many other dark pigmented plant foods. Foods containing anthocyanins have been proven improve cognition in the brain and prevent neurodegenerative diseases like Alzheimer’s and Parkinson’s Disease.
Omega 3 Fatty Acids- are fat substances found in foods like algae, chia seeds, fish, flax seeds, avocados, and many other foods. Omega 3 fatty acids help promote gut and brain health by reducing inflammation in both the gut and the brain. In addition, omega 3 fatty acids help to keep the brain healthy because it helps the brain maintain its structural integrity.
Anxiety, Depression, Parkinson’s, Autism, Multiple Sclerosis, Alzheimer’s, brain fog, migraines/headaches, mental fatigue, most mental and neurological issues, Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD), Small Intestinal Bacterial Overgrowth (SIBO), dysbiosis, Reflux/GERD, constipation, most digestive issues are all dependent on both a healthy gut & a healthy brain
What do I do Now?
There are a lot of effective tools that can help heal the gut and the brain and restore the connection that controls most of the body. As we discover more about the connection between the gut and the brain, we discover more and more beneficial treatments for those that are suffering. In fact, there are so many useful tools that trying to figure out which ones work for you can lead to treatment anxiety and an overwhelming feeling. It can be difficult to choose from all of the helpful diet changes, supplements, and therapies that can benefit your individualized health…
So, what are some ways that you can act today?
Treatments- Incorporate some of the treatments above to see if any are helpful for your individualized health journey.
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Bajaj, Jasmohan S., et al. “Posttraumatic Stress Disorder Is Associated with Altered Gut Microbiota That Modulates Cognitive Performance in Veterans withCirrhosis.” American Journal of Physiology-Gastrointestinal and Liver Physiology, vol. 317, no. 5, 2019, doi:10.1152/ajpgi.00194.2019.
Carissimi, Claudia, et al. “Functional Analysis of Gut Microbiota and Immunoinflammation in Children with Autism Spectrum Disorders.” Digestive and Liver Disease, vol. 51, no. 10, 2019, pp. 1366–1374.,doi:10.1016/j.dld.2019.06.006.
Grochowska, Marta, et al. “Gut Microbiota in Neurological Disorders.” Archivum Immunologiae Et Therapiae Experimentalis, vol. 67, no. 6, 2019, pp. 375–383., doi:10.1007/s00005-019-00561-6.
Hemmings, Sian M.J., et al. “The Microbiome IN Posttraumatic Stress Disorder and Trauma-Exposed Controls: An Exploratory Study.” Psychosomatic Medicine, vol. 79, no. 8, 2017, pp. 936–946., doi:10.1097/psy.0000000000000512.
Karl, J. Philip, et al. “Effects of Psychological, Environmental and Physical Stressors on the Gut Microbiota.” Frontiers in Microbiology, vol. 9, 2018, doi:10.3389/fmicb.2018.02013.
Malan-Muller, Stefanie, et al. “The Gut Microbiome and Mental Health: Implications for Anxiety- and Trauma-Related Disorders.” OMICS: A Journal of Integrative Biology, vol. 22, no. 2, 2018, pp. 90–107., doi:10.1089/omi.2017.0077.
Palsson, Olafur S., and William E. Whitehead. “Psychological Treatments in Functional Gastrointestinal Disorders: A Primer for the Gastroenterologist.” Clinical Gastroenterology and Hepatology, vol. 11, no. 3, 2013, pp. 208–216., doi:10.1016/j.cgh.2012.10.031.
Rice, Matthew W., et al. “Gut Microbiota as a Therapeutic Target to Ameliorate The Biochemical, Neuroanatomical, and Behavioral Effects of Traumatic Brain Injuries.” Frontiers in Neurology, vol. 10, 2019, doi:10.3389/fneur.2019.00875.
Winter, Aimee N., and Paula C. Bickford. “Anthocyanins and Their METABOLITES as Therapeutic Agents for Neurodegenerative Disease.” Antioxidants, vol. 8, no. 9, 2019, p. 333., doi:10.3390/antiox8090333.
Wu, Justin CY. “Psychological Co-Morbidity in Functional Gastrointestinal Disorders: Epidemiology, Mechanisms and Management.” Journal of Neurogastroenterology and Motility, vol. 18, no. 1, 2012, pp. 13–18., doi:10.5056/jnm.2012.18.1.13.
Zhang, Zhicheng, et al. “The Neuroprotective Effect of Tea Polyphenols on the Regulation of Intestinal Flora.” Molecules, vol. 26, no. 12, 2021, p. 3692., doi:10.3390/molecules26123692.