Irritable bowel syndrome, or IBS, is a syndrome characterized by bloating, abdominal distention, gas, pain, diarrhea and/or constipation. Not to be confused with inflammatory bowel disease (the umbrella term for Crohn’s Disease and Ulcerative Colitis), which is an autoimmune disease that affects the GI tract and is associated with chronic inflammation, IBS is said to be the most common gastrointestinal (GI) disorder, affecting anywhere from 10-15% of the world’s population.
Though the cause of IBS is unknown, and there is no known cure, dietary management can be effective in managing the often unpleasant, and embarrassing, symptoms of IBS. One dietary therapy that has shown promise is the low FODMAP elimination diet.
But what on earth is a FODMAP? When I first heard this term when I was a dietetic intern, training to become a dietitian, I thought it was a drug or a type of bacteria, or maybe some trendy new food I hadn’t heard of. FODMAPs actually refer to sugars (short chain carbohydrates) that are found in various foods that affect our gut bacteria. These short chain carbohydrates are poorly digested and lead to either increased fermentation and gas production (“beans, beans, they’re good for your heart, the more you eat the more you…”), or may draw water into the gut and lead to diarrhea.
FODMAP is an acronym that stands for fermentable fructans/oligosaccharides, disaccharides, monosaccharides, and polyols. Unless you remember anything from high school science class, this probably sounds like a foreign language. To put it simply: fructans/oligosaccharides are found in beans/legumes, garlic, onions, dried fruits, wheat, artichokes, etc. Disaccharides refer to lactose-containing foods (see: lactose intolerance), monosaccharides are simple sugars and sources of fructose (apples, honey, high fructose corn syrup, asparagus, etc.), and polyols refer to sugar alcohols (hello, anything “sugar free”) and foods such as mushrooms and cauliflower. These are just a handful of high FODMAP foods; the actual list is very extensive and rather shocking.
The low FODMAP diet is an elimination diet where all of the major high FODMAP foods are eliminated for a minimum of two weeks, but ideally for six weeks. At this point, symptoms of IBS should be less severe. Slowly, foods from each FODMAP group are added back into the diet. With the guidance of a registered dietitian, you will decide on the best way to add them back and track your symptoms; I usually just ask clients what food they miss the most and have that be the first group they start to add back in. The results may surprise you; some common foods that I hear cause the most issues are apples, onions, and garlic.
It is important to address several things, notably that this is a diet for symptom management, not a cure for a disease. It is also not a test for food allergies, so prior to starting a low FODMAP diet, diseases such as Celiac disease should be ruled out and gluten should be eliminated. That being said, people may find that they are intolerant to wheat but can tolerate it in small doses, which can be said about any of the FODMAP foods; smaller quantities may be okay, but you may not be able to dive into the garlic bread bowl or bean dip without symptoms later. You should also always do this diet under the instruction of a registered dietitian experienced in the FODMAPs to ensure that your diet remains balanced and not lacking in any important macro- or micronutrients. There are also lower FODMAP foods that may cause symptoms (a common one is broccoli), so tracking how you feel is vital.
On a side note, at the hospital I work at, as a pediatric GI dietitian, we followed the elimination diet for a week as a “challenge”. Below is a sample day in the life of the diet that I followed:
Sandwich: gluten free bread, almond butter, small ripe banana, cinnamon
Pea protein based yogurt
Salad with low FODMAP veggies (arugula, spinach, cucumber, carrots), grilled salmon made with salt and pepper, quinoa, ¼ cup chickpeas, 1/8 avocado, balsamic vinegar
4 cheddar cheese cubes
1 handful almonds
Gluten free brown rice pasta
Chicken tenders breaded with gluten free panko, topped with diced tomatoes and pinch of shredded mozzarella