Between 8% and 20% of people in the US have irritable bowel syndrome (IBS), which represents $1.35 billion in direct and $205 million in indirect medical expenses. Half of the time that a person sees a gastroenterologist, it’s in regards to IBS. Digestive disorders interfere with quality of life. If you’ve got IBS or some other digestive disorder, you know that when you’re not feeling great, everything in your life is affected by it. Most people find that food is a major trigger for IBS symptoms. (R) A low FODMAP diet is the most researched dietary strategy to help with IBS.
What are FODMAPs?
FODMAP is an acronym for “fermentable oligosaccharides, disaccharides, monosaccharides, and polyols”. FODMAPs are types of carbohydrates that are not well absorbed, and also highly fermentable by bacteria that live in the gut. The FODMAPs pull water into the intestinal tract and feed bacteria in the gut which produce gas. This leads to bloating, distention, and altered gut motility. (R)
What you end up with is an uncomfortable gut that is full of water and gas. Some people experience constipation, diarrhea, or even both. Following a low FODMAP diet, which includes limiting and significantly reducing the consumption of higher FODMAP foods, has been found to alleviate symptoms in persons with IBS. (R)
A low FODMAP diet increases the health of the gastrointestinal endocrine cells. These cells interact with one another and the nervous system to regulate various functions of the gastrointestinal tract, including motility, absorption, and sensation. (R)
FODMAPs are found in many foods, mostly being dairy and plant-based foods. Lactose, fructose, fructans, galacto-oligosaccharides, and polyols (sorbitol, mannitol, xylitol, and maltitol) are examples of FODMAPs. They are poorly absorbed because we either cannot digest them because we lack the enzymes to break them down, or it takes a long time to digest them, which leads to an increased chance of fermentation by gut bacteria. (R)
FODMAPs Can Be Good
FODMAPs aren’t always harmful, as they increases stool bulk, increase calcium absorption and modulate immune function. They also have the ability to lower cholesterol, triacylglycerols, and phospholipids, which are generally important for a healthy cardiovascular system. They feed Bifidobacteria, a beneficial and nonpathogenic intestinal bacteria. (However, if you’ve got too much bacteria in the small intestine, then it doesn’t really matter whether it’s a beneficial bacteria or not, because too much bacteria in the wrong place will create havoc on digestion.)
FODMAPs are fermented by bacteria, which in turn produce the short-chain fatty acids acetate, propionate, and butyrate. Short chain fatty acids are good for the colon and have been found to have a protective affect against colon cancer. (R)
FODMAPs tends to be dose dependent and additive, meaning that some people may be able to eat a little bit of FODMAPs, but once they eat too much, their symptoms of IBS will appear. (R)
Small Intestinal Bacterial Overgrowth (SIBO)
Small intestinal bacterial overgrowth (SIBO) is increased growth of bacteria that normally reside within the colon, but begin to flourish inside the small intestine. We normally have a little bit of bacteria in the small intestine, but SIBO is when there is way too much bacteria in the small intestine.
The two things that play a key role in the prevention of SIBO is having a strong acidic stomach to kill some of the bacteria, and normal gut motility (i.e. peristalsis/migrating motor complex) to flush the food and bacteria down to the colon. When the stomach isn’t acidic enough or gut motility is not functioning properly, bacteria have a greater chance of colonizing and thriving inside the small intestine.
Those who develop SIBO have similar (if not the same) symptoms as those with IBS, which includes the following but isn’t limited to: nausea, abdominal cramping, bloating, gas, diarrhea, and malabsorption of nutrients. SIBO can lead to nutritional deficiencies and malnutrition.
SIBO can be diagnosed by jejunal aspiration with at least 105 CFU/mL of bacteria. However, the most commonly used method for diagnosis is a hydrogen and/or methane breathe test.
Implementing a Low FODMAP Diet
*It is wise to have help from a dietitian or other healthcare professional when embarking on a restrictive diet, to ensure you are getting adequate nutrition.
The low FODMAP is an effective strategy to manage digestive symptoms associated with IBS. It’s important to understand that a low FODMAP diet can improve other more serious digestive disorders, such as inflammatory bowel disease (IBD, celiac disease, or even colon cancer). This improvement may mask the underlying true diagnosis, so be aware that you may think you have IBS, but in reality, you might actually have IBD or some other condition. Be sure to get an accurate diagnosis. (R)
A low FODMAP diet should be followed for 6-8 weeks. (R) However, a reduction in symptoms can be seen in relatively short time; a few days to a week. (R) Following the restriction phase for 6 weeks improves symptoms in up to 75% of people. The goal of the diet is to be able to add back some or hopefully all of the foods at some point. The restrictive phase should be followed for 4-6 weeks, and then foods should be added back slowly. (R)
More about the different FODMAPs:
Oligosaccharides - fructans and galacto-oligosaccharide (GOS) - found in wheat, rye, legumes, nuts, artichokes, onions, and garlic. We don’t have an enzyme that can break down and digest these, which means that nobody can digest and absorb them.
Disaccharide – the high FODMAP disaccharide is lactose, which is the sugar found in milk. Lactase is the enzyme that breaks down lactose, and the production of lactase in the body can decrease with age, certain ethnicities, and intestinal inflammation.
Monosaccharide – the high FODMAP monosaccharide is fructose, which is found in certain fruits like apples, mangoes, and pears, as well as honey, sugar snap peas, and other foods. Fructose is poorly absorbed in the small intestine, and it is a slow process. This gives bacteria in the small intestine an opportunity to consume fructose and flourish. Fructose is interesting, because it seems to be more of a problem when it is consumed in excess of glucose. Fructose is taken up by GLUT-5 transporters, but it is relatively “slow”. Glucose is taken up by GLUT-2 in the gut. When there is more glucose than fructose present in the gut, its helps increase the absorption rate of fructose, giving it less of a chance to cause digestive disturbances. (R)
Polyols – found in foods such as apples, pears, cauliflower, mushrooms, and snow peas. Some artificial sweeteners are polyols. Polyols, like fructose, are also slowly absorbed in the small intestine. Polyols absorb by diffusion. You can think of polyols being absorbed by passing through “holes” in the gut. If the gut is inflamed, the hole sizes may be smaller, which makes absorbing certain molecules like polyols much more difficult. Persons with celiac disease have been found to have reduced sizes of these pores or holes. (R)
High FODMAP Foods
Asparagus, artichokes, beetroot, broccoli, cauliflower, celery, garlic, leek bulb, legumes/pulses, onions, onion and garlic salts, snow peas, sugar snap peas, savoy cabbage, sun dried tomatoes, sweet corn
Apples, apricots, avocado, blackberries, cherries, currants, dates, figs, pears, mango, nashi pears, nectarines, nectarines, peaches, plums, prunes, watermelon
Milk and Dairy
Cow’s milk, goat’s milk, yogurt, soft cheese (ricotta and cottage cheese), cream, custard, ice cream, yogurt
Barley, rye, spelt, wheat
Beans, mature soybeans, split peas
Nuts and Seeds
Agave, high fructose corn syrup, honey, isomalt, mannitol, sorbitol, xylitol
Oolong tea, chamomile tea, fennel tea, carob tea, chicory root (inulin), fructooligosaccharide (FOS)
Low FODMAP Foods
Alfalfa, arugula, bamboo shoots, bean sprouts, ½ cup broccoli, green beans, bok choy, bell peppers, carrots, choy sum, cucumber, sweet corn (1/2 cob), green and red cabbage (common), eggplant, fennel, ginger, green onion (the green part only), fresh herbs, kale, lettuce, parsnip, canned pumpkin, radish, rutabaga, spaghetti squash, spinach, swiss chard, summer squash, tomato, turnip, zucchini, white potato, ½ cup sweet potato, watercress
Banana, Orange, clementine, tangelo, mandarin, grapes, cantaloupe, honeydew, blueberries, strawberries, raspberries, kiwi, lemons, limes, papaya, pineapple, rhubarb
Milk and Dairy
Lactose-free milk, lactose-free yogurts, hard cheeses (colby, havarti, parmesan, swiss), lactose free cottage cheese, lactose free cream cheese, dairy alternatives (almond milk, coconut milk, rice milk, hemp milk), lactose free sour cream, whipped cream, lactose free ice cream
Beef, chicken, eggs, fish, pork, tempeh, tofu
½ cup drained and rinse canned lentils, ½ cup drained and rinsed canned chickpeas, firm tofu, tempeh, 1 cup edamame
Gluten-free bread and sourdough spelt bread without high FODMAP ingredients (Udi’s White Sandwhich bread is approved), rice cereal, gluten free oats, gluten-free pasta, rice, quinoa, rice cakes, corn chips, millet, rice cakes, polenta, corn tortillas, gluten-free pretzels, gluten-free crackers, gluten free noodles
Nuts and Seeds (consume less than 10 nuts)
Nuts: Almonds, macadamias, peanuts, pecans, walnuts, pine nuts, nut butter made from low FODMAP nuts and without high FODMAP ingredients
Seeds: 2 T chia seeds, 2 T poppy seeds, 2 T pumpkin seeds, 1 T sesame seeds, 2 T sunflower seeds
brown sugar, dark chocolate, cocoa powder, palm sugar, pure maple syrup, stevia, vanilla, white sugar
*Read the ingredients on the label to make sure it doesn’t have any added high FODMAP ingredients. I think packaged things can be a hit or miss. Even packaged foods that seem to be low in FODMAPs may cause trouble. Just be aware of how these foods make you feel.
Low FODMAP Meal Ideas
- Oatmeal with toppings of your choice (nuts, seeds, low FODMAP fruits)
- Eggs with oatmeal
- French toast made with Udi's White Bread, topped with banana and blueberries
- Eggs with low FODMAP vegetables like zucchini
- Peanut Butter Toast topped with sliced banana
Lunch and Dinner
You’ll have to cook most if not all of your meals, therefore it’s wise to keep things relatively simple. The easiest thing to do is pick out a protein, like salmon, pick a carbohydrate source, like mashed potatoes, and then a veggie or two from the low FODMAP list. It’s also a really good idea to make sure you are making leftovers when you cook, as this saves time in the kitchen.
- Chicken fajitas
- Basil Pasta with tomatoes, chicken, and a salad
- Salmon with rice, salad, and green beans
- Chicken with rice, lentils, and summer squash
- Spaghetti with salad
- Rice cakes with nut butter and sliced banana
- Sliced banana topped with nut butter
- Low FODMAP fruit and nut bowl
- Gluten free pretzels
*Avoid all of the high FODMAP foods for at least 4 weeks; possibly for 6 weeks.
*You can do a hydrogen breath test to see if you have the ability to digest and absorb fructose and lactose appropriately. If you can absorb them, then there’s no reason to restrict these foods. (This would also lead to oligosaccharides and polyols being the culprit for your digestive issues.) (R)