Integrating Low FODMAP Strategies Into Your Practice to Treat Irritable Bowel Syndrome
by Michelle LaPlante
After being championed by researchers for the last few years as an alternative treatment for irritable bowel syndrome (IBS), low FODMAP diets have now begun to enter many physicians’ clinical practice. Gastroenterologist and physician nutrition specialist Maitreyi Raman, MD, MSc, FRCPC, Medical Director of Nutrition Services at University of Calgary, Canada, often treats patients with gastrointestinal (GI) issues who present with either dietary, nutrition, or malnutrition concerns. Dr. Raman spoke with Consultant360 about what clinicians need to know when prescribing the low FODMAP diet for their patients.
How has IBS been traditionally managed?
There has been a heavy emphasis on increasing fiber in patients’ diets to manage their IBS, but this approach has been only moderately to poorly effective. We would tell our patients, and for the most part it is true, that they were not consuming enough fiber (most North Americans consume less than 50% of their recommended fiber intake 1,2). Thus, our first-line management strategy would be soluble fiber, of which psyllium fiber is a classic example, and patients would be advised to increase their fiber and fluid intake and to exercise in moderation. There are few medications that have been successful in treating IBS.
What are some of the challenges associated with traditional approaches?
The strategies that we would use to manage IBS depended upon which type of IBS you had. There are 3 types: one type has constipation as its major symptom; a second type has diarrhea as its predominant symptom; and the third type is a mixed pattern IBS. This third type would have cramping, bloating, and gas associated with either constipation or diarrhea.
If a patient presented with the first type, the one with just constipation as the predominant symptom, the treatment emphasis would be on laxatives and fiber. We would recommend that the patient start with optimizing their fiber, and if that did not work, then we would focus on laxatives as a treatment plan. Laxatives could range from very effective ones such as polyethylene glycol 3350, which would be prescribed for something like a colonoscopy, to gentler laxatives. More recently, newer medications to manage constipation are now available. Examples of these medications include prucalopride and linaclitide. These newer agents have been very effective in helping a patient who has constipation as a primary symptom. However, these medications are expensive, and in the absence of adequate insurance coverage, financially prohibitive for many to use on a regular basis.
But if a patient had diarrhea-predominant IBS, then we would focus on anti-diarrheal medications such as loperamide, which would be somewhat effective, but were unsatisfactory to patients. Patients would often become constipated when taking loperamide, and achieving regularity was often challenging.
Medications such as amitriptyline have also traditionally been used to treat IBS. This drug is an antidepressant (a tricyclic agent), but we have found that very low doses of this medication and similar drugs are helpful in modulating some of the pain sensations that these patients are at risk for experiencing. If you look collectively at antidepressants, laxatives, and antidiarrheals, the success rate of all of these medications is probably about 50%.3
Additionally, many patients have features of all 3 types of IBS, which is what we call a mixed pattern. This means that patient symptoms include diarrhea, constipation, and pain, and there are very few pharmacologic strategies to successfully manage these symptoms.
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When did you start hearing about the low FODMAP diet as a viable treatment for IBS?
I first heard about the low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet from a physician standpoint around 2009, and over the past 7 years there has been a huge explosion of support in the medical literature for the efficacy of the low FODMAP diet for IBS. 4,5
When the concept of a low FODMAP diet was first introduced, the studies were all small and not the most methodologically robust. However, over the past couple of years, we have begun to see very positive results that support the low FODMAP diet as a way to manage IBS symptoms. The diet is gaining in popularity with multiple groups of health professionals. Researchers have tested the hypothesis in various patient groups with wide success in primarily managing bloating, cramping, and diarrhea. I would say that the low FODMAP diet today is now among the top two, if not the top 3, behavioral and lifestyle changes that we as physicians recommend to patients with IBS to manage their disease.
What exactly is the low FODMAP diet, and what is its connection to the gut microbiome?
The premise of the low FODMAP diet is that you restrict, or you eliminate, foods that have a high potential to be fermented in the gut. (Table 1) These types of foods cause fluid shifts in the intestine, which can result in bloating and gas. They can also change the types of bacteria in the intestine, which we collectively refer to as the gut microbiome. Higher FODMAP foods can result in diarrhea, as well as pain, so the theory is that these symptoms can be minimized by restricting foods that cause fermentation.
Table 1. Examples of high FODMAP foods and products to reduce or avoid.
- Fruits such as apples, apricots, blackberries, cherries, mango, nectarines, pears, plums, and watermelon, or juice containing any of these fruits
- Canned fruit in natural fruit juice, or large quantities of fruit juice or dried fruit
- Vegetables such as artichokes, asparagus, beans, cabbage, cauliflower, garlic and garlic salts, lentils, mushrooms, onions, and sugar snap or snow peas
- Dairy products such as milk, milk products, soft cheeses, yogurt, custard, and ice cream
- Wheat and rye products
- Honey and foods with high-fructose corn syrup
- Products, including candy and gum, with sweeteners ending in “–ol,” such as:
- sorbitol
- mannitol
- xylitol
- maltitol
Table 1. high FODMAP foods and products to reduce or avoid. (From Eating, diet, & nutrition for irritable bowel syndrome. NIH National Institute of Diabetes and Digestive and Kidney Diseases website. https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome/eating-diet-nutrition. Accessed February 17, 2017.)
Do people with IBS have problems processing certain types of foods?
No, I would say that patients with IBS are more sensitive to the effects of these types of foods. There is no fundamental structural problem in the gut for patients with IBS; they have a normal, healthy, functioning intestine like anyone else without IBS. However, the problem is that their neurons are more sensitive to the way that they perceive changes of distention, pain, and bloating. If we can minimize foods that have this effect in the IBS population, these patients will feel better and their symptoms will improve.
What kinds of foods should be avoided on a low FODMAP diet? (continued on next page)
The second items that we recommend avoiding on a low FODMAP diet are milk and dairy products. Lactose can be a large, fermentable carbohydrate in the gut that can predispose towards symptoms.
It is also important that a skilled dietitian work with the person who has IBS. A dietitian can recommend fruits and vegetables that have a lower FODMAP content and yet preserve adequate nutrition in the diet so that the patient does not risk nutritional deficiencies. The risk for nutritional deficiencies is the reason why I would never recommend that any patient try to implement a low FODMAP diet independently, without consulting with a physician and dietitian, or use a low FODMAP diet as a long-term strategy to manage symptoms. The primary risk with this diet would be with calcium deficiency, as well as fiber deficiency. An experienced dietitian will be able to manage some of the fiber deficiencies that arise by recommending foods that are lower in FODMAP but still allow patients to retain their fiber intake.
Should people with IBS maintain a low FODMAP diet for the rest of their lives, or can they eventually reintroduce some formerly restricted foods into their diet?
The low FODMAP diet was never intended to be a long-term diet; it is recommended to be fairly strictly followed for a maximum of 6 to 8 weeks. At the 6 to 8 week mark, and usually sooner than that, patients should tell you whether they observe an improvement in their symptoms. The low FODMAP data4,5 suggest that more than two-thirds of patients will have a good response to the low FODMAP diet.
Patients generally start feeling better within a few weeks of starting the diet, but we counsel them up front that this is not a diet that is meant to be used long term because of the risks of nutrient deficiencies, as well as the unknown effects—right now—on the microbiome. We recommend that higher FODMAP foods be reintroduced under a dietitian’s guidance at the end of the 6 to 8 week period. The ultimate goal is gradual reintroduction of the various domains of the low FODMAP categories until the patient’s diet has expanded with as minimal restriction as possible.
Are you starting to see physicians integrate the low FODMAP diet into their prescriptions for patients with IBS? Is it becoming more prevalent?
Yes, it is becoming more prevalent. With more continued medical education and continued professional development, you will see more physicians adopt this diet into their treatment plans for IBS. The low FODMAP diet is often a hot topic at many gastrointestinal conferences, and data on the diet’s efficacy is updated and presented at these meetings. Clinicians will come home and share new information with colleagues and engage the dietitian community to co-develop guidelines on how to manage IBS with the low FODMAP diet. Doctors are finding that that this diet is the most practical and cost-effective strategy for IBS patients.
You mentioned that a dietitian should be involved in educating the patient about the low FODMAP diet. Who else should be involved in the patient’s care?
It would not be practical for a gastroenterologist to see every patient with IBS, and it would not be needed either, because these patients do not really require any specialized testing to have a diagnosis. The reality is that most patients with IBS are diagnosed and managed by the primary care physician, who, ideally, should refer that patient to a registered dietitian who is familiar with the low FODMAPs diet. I use the term “familiar” or “experienced,” because even within the dietitian community, there are experts within certain areas.
A GI dietitian with expertise in the low FODMAP diet will be able to initiate the diet and then reintroduce foods after elimination, and there should ideally be an experienced individual guiding that process. However, a third of these patients will still have ongoing symptoms despite diligently trying and following the low FODMAP diet, so for these patients it would be best to refer them to a gastroenterologist.
What else should a clinician consider before prescribing a low FODMAP diet?
Some patients who have a long history of GI symptoms, even before seeing their doctor or dietitian, have experimented quite substantially with their diet and may be exhibiting signs of orthorexia; they may have eliminated all sorts of foods, or they may have fixed ideas about what works and what does not work for them. If they have already tried a lot of these elimination types of behaviors on their own, they may have lost weight, or they may be at risk of developing nutritional deficiencies. I would probably not recommend the low FODMAP diet for that type of patient.
One last point I should mention is that probiotics have also been widely used in the management of IBS. Probiotics are a difficult topic in the sense that they come in all sorts of shapes and sizes, with all sorts of bacteria, and different types of bacterial counts. However, broadly speaking, probiotics have a role in managing IBS. Many patients do have symptomatic improvement after a trial of probiotics. From my perspective, I often find that the low FODMAP diet and probiotics work well together—I will often recommend a GI-friendly probiotic like Bifidobacterium infantis in combination with the low FODMAP diet, and, anecdotally, I have had a lot of success with that approach.
References
1. Fedorak RN, Vanner SJ, Paterson WG, Bridges RJ. Canadian Digestive Health Foundation Public Impact Series 3: irritable bowel syndrome in Canada. Incidence, prevalence, and direct and indirect economic impact. Can J Gastroenterol. 2012;26(5):252-6. doi:10.1155/2012/861478.
2. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. http://health.gov/dietaryguidelines/2015/guidelines/. Accessed February 10, 2017.
3. Lacy BE, Weiser K, De Lee R. The treatment of irritable bowel syndrome. Therap Adv Gastroenterol. 2009; 2(4): 221-238. doi:10.1177/1756283X09104794.
4. Nanayakkara WS, Skidmore PM, O'Brien L, Wilkinson TJ, Gearry RB. Efficacy of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date. Clin Exp Gastroenterol. 2016;9:131-142. doi:10.2147/CEG.S86798.
5. Ross E, Lam M, Andrews C, Raman M. The low FODMAPs diet and IBS: A winning strategy. J Clin Nutr Diet. 2016;2:1. http://clinical-nutrition.imedpub.com/the-low-fodmaps-diet-and-ibs-a-winning-strategy.php?aid=8983. Accessed February 16, 2017.