Gut-Brain Connection in IBS

Lesley Hermann PhotoTHE GUT-BRAIN CONNECTION IN IBS by Lesley Herrmann NC, BCHNTM owner and founder of Awakened Taste Nutrition

It is estimated that about 11 per cent of the population worldwide are affected by irritable bowel syndrome (IBS) (Canavan et al, 2014). In 2005, The Canadian Society of Intestinal Research estimated that up to 22 per cent of the Western population was affected by this condition (Care, 2005). Although more women are diagnosed with IBS than men, it is believed by many practitioners that men experience symptoms of IBS just as often as women, but are less likely to report them to their doctor or seek medical help (Mercola, 2016). IBS is a diagnosis that is given when symptoms of chronic diarrhea, constipation, gas, bloating, and abdominal pain persist after structural abnormalities, infection, metabolic disturbances and other GI disorders are ruled out.

What are doctors doing to support their patients with IBS if physiological triggers are not present? Many practitioners resort to medications to alleviate symptoms, although this approach does not identify or support the root cause. Unfortunately, these medications can induce side- effects that are identical to the symptoms of IBS itself. For example, Lubiprostone, used to treat constipation associated with IBS dominated by constipation, can cause nausea, diarrhea, and abdominal pain (Lacy et al., 2009). 

Do psychological aspects play any role in IBS? Evidence from clinical and experimental studies has also shown that psychological stressors have distinct effects on intestinal sensitivity, secretion (including a reduction in hydrochloric acid), motility, permeability, and a reduced regenerative capacity of the GI mucosa (Qin et. al., 2014) (Konturek PC et al., 2011). It is estimated that 40 to 60 per cent of patients with IBS seeking medical help also experience depression, anxiety, or somatization and that these disturbances affect coping ability and illness- associated behaviors (Hopkins, 2013). Stressors also have a close correlation with mucosal immune function associated with the microbiome (Qin et al., 2014). By increasing permeability of the epithelium and weakening the diversity and integrity of the microbiome, an individual can become more prone to developing food sensitivities and allergies, which then lead to other or more severe symptoms of IBS as well as intestinal inflammation and the onset of other, more serious GI disorders (Konturek PC et al., 2011).

In some cases, patients may see the doctor with symptoms of IBS and depression, but are doctors spending enough time investigating whether these symptoms stem from the same root cause? It is estimated that one in eight patients with IBS is offered an anti-depressant (Grover et al., 2011). Research from Dr. Kelly Brogan (2013) suggests that depression is likely a symptom of inflammation and that serotonin deficiency (historically a theory as to the cause of depression) is likely an effect of this inflammation. Recall that inflammation is triggered by the response of T-cells to environmental antigens. Since our gut lining is the first line of defense against the external environment and home to more than 70 per cent of our immune system, it may be in some cases that the state of our gut is the cause of the depression, rather than the reverse (Brogan, 2013). 

In the book The Second Brain, Dr. Michael Gershon describes the current understanding of nervous disorders of the stomach and intestine and identifies a strong connection between the brain in our head and the “brain” in our gut. He reminds us that when we experience emotional nervous energy, we may feel nausea, stomach or gut pain, and or a loss of appetite (Gershon 1998). Why does this happen? There exists a subconscious communication link between the brain and the gut, which takes place through the autonomic nervous system (ANS) including the hypothalamus, spinal cord, nerve fibers, and nerve receptors (Hopkins, 2013). Research suggests that the brain and the GI tract mature from the same part of the embryo and that this communication link develops during the fetal stage of development (Hopkins, 2013).

From a nutritional perspective, there are a number of nutrients that can support and fortify the brain and the gut.

Melatonin. The neurotransmitter melatonin is an important mediator of the gut-brain axis and has been shown to exhibit protective effects against stress-induced lesions in the GI tract. (Konturek PC, 2011). Melatonin has also been shown to regulate gastrointestinal motility, local anti-inflammatory reactions, and the moderation of visceral sensation, helping to modulate pain (Kewin Tein Ho, et al., 2014). Being a promoter of sleep, melatonin is essential for healing the gut because this is when most gut repair takes place. In the brain, melatonin has a strong neuroprotective effect, especially when oxidative stress and neural inflammation is high (Dun- Xian, 2010). Serotonin is a precursor to melatonin and requires the amino acid tryptophan (5- HTP).

Serotonin. According to Costedio et al. (2007), the neurotransmitter serotonin plays a critical role in the activation of neural reflexes associated with intestinal secretion, motility, and sensation. Although research is somewhat inconclusive about the specific role of serotonin in the gut, their findings suggest that people with IBS show irregularity in serotonin signaling (Costedio et al., 2007). Another study suggested supporting results; individuals with IBS dominated by either constipation or diarrhea showed a decrease in uptake of serotonin into the epithelial cells of the intestines compared to healthy individuals, as suggested by higher circulating blood levels (Mawe et al., 2013). Additionally, lower levels of serotonin in the brain showed a decreased mood in susceptible individuals (Jenkins et al 2016). However, the study concluded that this correlation could not happen in isolation, but rather some other system, such as neurotransmitters or genetics, must also play a role in the interaction between low serotonin and decreased mood. (Jenkins et al., 2016). The serotonin deficiency in this study was induced by a prolonged tryptophan-deficient diet.

Tryptophan (5-HTP). Tryptophan is an essential amino acid used in the synthesis of melatonin and serotonin. If serotonin or melatonin levels are low, 5-HTP is the best nutrient to rebuild stores (Bauman, 2014). Food sources of 5-HTP include beef liver, salmon, chicken, turkey, and collard greens.

Pantothenic Acid (B5). B5 is considered the anti-stress vitamin as is a precursor to cortisol and other adrenal hormones as well as serotonin. Supportive food sources include beef liver, shiitake and other mushrooms, chicken, and turkey.

Omega-3 fatty acids. These essential fats help support brain and adrenal gland function and help soothe the inflamed intestinal lining. Food sources include cod liver oil, grass-fed beef and pasture-raised eggs, and cold water fish like salmon and sardines.

Magnesium. This mineral is important for stress management, as it aids in muscle relaxation. People who suffer from stress are often low in Magnesium (Richardson, 2014). It is an important electrolyte that helps maintain proper mineral balance, important for the production of HCl, and for those with IBS dominated by diarrhea. It helps soften stool and can relieve constipation for IBS dominated by constipation suffers as well (Bauman, 2014).

Protein. The intestinal tract is one of the fastest regenerating tissues in the body; however regeneration of the tissue in the GI tract may be compromised when protein digestion and assimilation is impaired (Wilson, 2010). The intestinal tract may degrade over time in people with IBS if food allergies/sensitivities are not addressed, the diet lacks adequate protein, the body is under continuous stress, and/or the body has mineral imbalances or deficiencies (Bauman, 2014) (Wilson, 2010). Protein provides essential amino acids and peptides needed for hormone, neurotransmitter, and enzyme production (including digestive enzymes) which are all important for soothing an irritable bowel (Bauman, 2014). Protein is important for those experiencing stress as it is soothing and supportive of the nervous system, and animal protein is essential for providing tryptophan (Bauman, 2014).

Daily protein amounts should be between 1.2 and 2 grams per kilogram of body weight per day, depending on stress level (Bauman, 2014); people with severe stress levels should aim for the higher quantity. The best source of protein is found in organic, pasture-raised animals, wild cold water fish such as salmon, sardines, cod, and halibut, and whey protein, for those who can tolerate dairy.


As we can see from the research highlighted here, there is plenty of evidence that shows that the brain and the gut have a very tight link. For some, psychological stress may be the underlying cause of IBS while for others, a weakened or damaged gastrointestinal tract is causing symptoms of depression and anxiety. This broad spectrum of research suggests that it is important to investigate and treat IBS holistically because of the strong gut-brain interactions. In many cases, psychological and physiological factors need to be addressed in an integrative way that includes lifestyle measure to address stress and anxiety and dietary measures to fortify cognitive and intestinal function.


Brogan, K. 2013. Fire in the Mind: The depression-Inflammation Connection. The Carlat Report Psychiatry. Nov 2013. 11(11).

Bauman, E., Friedlander, J. (2014). Therapeutic Nutrition Textbook. Penngrove, CA: Bauman College.

Canavan, C., West, J., Card, T. (2014). The epidemiology of irritable bowel syndrome. Clinical Epidemiology. 2014; 6:71-80

Care, A. (2005). The Costly Toll of IBS. GI Society-Canadian Society of Intestinal Research. First published in Inside Tract newsletter. 2005 September (151).

Costedio, M.M., Hyman, N., Mawe, G.W. (2007). Serotonin and its role in colonic function and in gastrointestinal disorders. US National Library of Medicine, National Institute of Health. 2007 March. 50(3): 376-388.

Dun-Xian, T. (2010). Melatonin and Brain. Current Neuropharmacology. September 2010. 8(3): 161.

Gershon, M. (1998). The Second Brain: a groundbreaking new understanding of nervous disorders of the stomach and intestine. HarperCollins Publishers Inc., New York, NY.

Grover M., Drossman D. A. (2011). Centrally acting therapies for irritable bowel syndrome. Gastroenterol. Clin. North Am. 40, 183–20610.1016/j.gtc.2010.12.003.

Hopkins. (2013). Irritable Bowel Syndrome – Introduction. Available at: Last accessed Jan 16 2018.

Jenkins T., Nguyen J., Polglaze K., Bertrand P. (2016). Influences of Tryptophan and Serotonin on Mood and Congnition with a Possible Role of the Gut-Brain Axis. Nutrients. 2016 Jan 20; 8((1): 56. DOI: 10.3390/nu8010056.

S. Kewin Tein Ho, Reuben, K.M.W, and Khek, Y.H. (2014). Melatonin for the treatment of irritable blowl syndrome. World journal of Gastroenterology. 2004 Mar 14; 20(10): 24.

Konturek PC, Brzozowski T., Konturek SJ. (2011). Stress and the gut: Pathophysiology, clinical consequences, diagnostic approach and treatment options. Journal of Physiology and Pharmacology December 2011; 62(6):591-9.92-2498.

Lacy, B., Weiser, K., and DeLee, R., 2009. The Treatment of Irritable Bowel Syndrome. Therapeutic Advances in Gastroenterology. 2009. July; 2(4):221-238.

Mawe, G., Hoffman, J. 2013. Serotonin Signaling in the Gastrointestinal Tract: Functions, dysfunctions, and therapeutic targets. Nat Rev Gastroenterol Hepatol. 2013 Aug: 10(8): 473-786.

Mercola, D. (2016). How GMO’s Pesticides and Processed Foods Contribute to Common Bowel Disorders. Available at disease-rise.aspx. Last accessed January 1, 2018.

Hong-Yan Qin, Chung-Wah Cheng, Xu-Dong Tang, and Zhoa-Xiang Bian. (2014). Impact of psychological stress on irritable bowel syndrome. World Journal of Gastroenterology. October 21, 2014; 20(39): 14126-14131.

Richardson, A. (2014). Vitamins that deplete under stress. Live Strong. February 10, 2014. Available at: stress/. Last updated Aug 14 2017.

Wilson, L. (2010). Colitis, Enteritis, and Irritable Bowel Syndrome. The Center for Development. December 2010. Available at: Last accessed June 2 2014.

Lesley Herrmann NC, BCHNTM

Lesley is a Board Certified Holistic Nutritional Consultant Certified Wellness Coach. She earned her certifications through Bauman College and US Corporate Wellness, respectively. Prior to her career in nutrition, Lesley worked as an engineer at the National Renewable Energy Laboratory in Golden, Colorado. A year into her engineering career, she was diagnosed with celiac disease, which spurred her to study holistic nutrition. Fascinated by the role of food and emotional wellbeing in long-term health, she soon turned her curiosity into a passion and a mission to help others regain their health through diet and lifestyle practices. Today, she is the owner and founder of Awakened Taste Nutrition, where she empowers individuals to take control of their health by providing the education, guidance, and support needed to achieve personal transformation.

Share this post:

Comments on "Gut-Brain Connection in IBS"

Comments 0-10 of 0

Please login to comment