A Functional Nutritionist's Take on Irritable Bowel Syndrome
Irritable Bowel Syndrome: A Functional Nutrition Approach By Nathan Slinkard, MS, RD, LD, CLT
The number one condition I help with is irritable bowel syndrome. It’s a chronic, functional bowel disorder that doesn’t just go away with medication even though that is the primary way it is treated. This condition affects 1 in 8 Americans and is responsible for 1 in 5 visits to a Primary Care Provider.
There is no specific test for IBS but at least two of the following must occur once a week for 3 months: pain and discomfort related to defecation, a change in the frequency of defecation, or a change in stool consistency. There are three main types: diarrhea-predominant (IBS-D), constipation-predominant (IBS-C), and a mixture of the two (IBS-M).
A variety of medications may be used to cover up symptoms in the short term such as antidepressants, prokinetics, antibiotics, pain medications, and laxatives. However, these carry side effect risks and can make matters worse in the long run. If nutrition and lifestyle are addressed, there is a greater likelihood of symptom relief. This is why, in addition to a physician, you should work with a registered dietitian who specializes in IBS.
What Causes IBS?
Every case is different, but the most commonly proposed etiologies for IBS include foodborne illness, “visceral hyperalgesia, intestinal permeability, immune activation, altered gastrointestinal motility, autoimmunity, and alteration of the gut microbiome” (1).
Often, people undergo extensive testing to rule out Intestinal Bowel Disease (Crohn’s and Ulcerative Colitis), ulcers, food allergies, and Celiac Disease before they are given an IBS diagnosis.
What Do I Eat in a Flare-Up?
Proper nutrition during an IBS flare-up may look significantly different than a typical day. If someone is losing fluids through frequent diarrhea or vomiting, they should focus on hydrating with water and electrolytes. For severe constipation, your doctor may recommend a liquid or soft diet. It is important to chew food thoroughly, avoid high-fat foods and alcohol, and get plenty of rest.
What About Gut Bacteria?
Probiotics have become a popular approach in the treatment of IBS. I have personally seen them cause symptoms as often as they relieve them, however. This is often due to unaddressed underlying issues such as unhealthy food intake, stress, and gastrointestinal inflammation.
Bacterial overgrowth in the small and/or large intestines is common in IBS (2). Probiotics may or may not help, depending on the strain, when small intestinal bacterial overgrowth or intestinal methanogen overgrowth is already rampant. Antimicrobial herbal protocols or gut-specific antibiotics are the main ways to address bacterial overgrowth. However, addressing the underlying cause of bacterial overgrowth (such as altered gut motility) is essential due to the high rates of relapse.
Factors that increase the risk of bacterial overgrowth include antibiotics, proton pump inhibitors (like omeprazole and pantoprazole), abdominal surgeries, and foodborne illness.
What About Food Intolerances?
One of the most common IBS diets is the low FODMAP diet. This is a way to address a potential issue with food intolerance. Research suggests about 1 in 2 people with IBS may achieve significant relief with this approach (3). However, it is important to work with a registered dietitian to ensure the diet is balanced and nutritionally adequate. FODMAPs stand for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols which are carbohydrates that may not be fully digested and contribute to IBS symptoms and gas. Some common FODMAPs are lactose (think ice cream, milk, and yogurt), sugar alcohols (found in some sugar-free foods and drinks), and many fruits and vegetables (like beans, onion, apples, and watermelon).
Foods high in FODMAPs are restricted for 4-6 weeks and then reintroduced back one category at a time. The downsides of this diet are 1) it can be challenging to follow 2) it can negatively harm good gut bacteria and 3) it does not address inflammation.
What About Inflammation?
Research suggests at least 1 in 2 people with IBS have a food sensitivity (4). A food sensitivity is a delayed immune system reaction to a food antigen causing systemic, low-grade inflammation. This inflammation can contribute to a variety of symptoms including diarrhea, constipation, pain, bloating, rashes, fatigue, brain fog, migraines, joint pain, headaches, and more.
If one or more of these symptoms is present, it is helpful to assess for food sensitivities (sometimes referred to as non-IgE-mediated food allergies). Testing for food sensitivities via IgG is controversial. The American Academy of Allergy Asthma and Immunology reports that IgG has “never been scientifically proven to be able to accomplish what it reports to do,” and that “the presence of IgG is likely a normal response of the immune system to exposure to food.” IgG is also not involved in Type 4 Hypersensitivity which is the most common food sensitivity pathway involved in IBS, migraine, and fibromyalgia.
A test that is over 90% accurate, on the other hand, is the Mediator Release Test (MRT) which clearly demonstrates scientific methodology. Chemical mediators (histamine, prostaglandins, cytokine, etc.) are released by white blood cells which cause inflammation. This
blood tests analyze individualized inflammatory responses to 176 foods by measuring chemical mediator release.
Research on MRT-based elimination diets demonstrated a 67.8% reduction in global symptoms of IBS and significantly improved quality of life, pain, vitality, and emotional well-being (5 and 6).
What About Stress?
Visceral hypersensitivity is common in IBS and refers to a heightened experience of pain related to overly sensitive nerve endings in the gut. To reduce this hypersensitivity, mindfulness-based approaches such as deep breathing may help improve symptoms. One nervous system approach was just as effective as the Low FODMAP diet in reducing IBS symptoms and produced greater improvements in mental health (7).
Conclusion
A personalized, holistic approach to IBS that considers both short-term and long-term health is essential. Many factors may contribute to symptoms including poor diet, high stress, bacterial overgrowth, food intolerances, and inflammation. Although IBS is common and many people suffer unnecessarily, there are plenty of high-quality approaches based on solid scientific evidence. One of the best ways to manage your IBS is to work with a functional medicine physician and a dietitian.
Nathan Slinkard, MS, RD, LD, CLT Registered Dietitian and IBS Expert
References
Takakura W, Pimentel M. Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome - An Update. Front Psychiatry. 2020 Jul 10;11:664. doi: 10.3389/fpsyt.2020.00664. PMID: 32754068; PMCID: PMC7366247.
Wielgosz-Grochowska JP, Domanski N, Drywień ME. Efficacy of an Irritable Bowel Syndrome Diet in the Treatment of Small Intestinal Bacterial Overgrowth: A Narrative Review. Nutrients. 2022 Aug 17;14(16):3382. doi: 10.3390/nu14163382. PMID: 36014888; PMCID: PMC9412469.
Black CJ, Staudacher HM, Ford AC. Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2022 Jun;71(6):1117- 1126. doi: 10.1136/gutjnl-2021-325214. Epub 2021 Aug 10. PMID: 34376515.
Fritscher-Ravens A, Pflaum T, Mösinger M, Ruchay Z, Röcken C, Milla PJ, Das M, Böttner M, Wedel T, Schuppan D. Many Patients With Irritable Bowel Syndrome Have Atypical Food Allergies Not Associated With Immunoglobulin E. Gastroenterology. 2019 Jul;157(1):109-118.e5. doi: 10.1053/j.gastro.2019.03.046. Epub 2019 May 15. PMID: 31100380.
Patenaude J & Bright D. Clinical improvement of IBS, migraine, fibromyalgia, and arthritis using elimination diets based on mediator release blood testing. Journal of the American Dietetic Association, Volume 109, Issue 9, Supplement, 2009, Page A32, ISSN 0002-8223, https://doi.org/10.1016/j.jada.2009.06.092.
Zarini GG, McLean MA, Delgado SI. Is Personalized Dietary Therapy Effective for Individuals with Irritable Bowel Syndrome? American Journal of Lifestyle Medicine. July 2022. doi:1177/15598276221112309.
Peters SL, Yao CK, Philpott H, Yelland GW, Muir JG, Gibson PR. Randomized clinical trial: the efficacy of gut-directed hypnotherapy is similar to that of the low FODMAP diet for the treatment of irritable bowel syndrome. Aliment Pharmacol Ther. 2016 Sep;44(5):447-59. doi: 10.1111/apt.13706. Epub 2016 Jul 11. PMID: 27397586.
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