Since IBS is a digestive disorder, it makes sense that there is a special diet for IBS, right? Ummmm….not exactly. There are definite general guidelines that you can follow and there are a few dietary approaches that you can use to reduce the symptoms of IBS, but there is no one, universally agreed on diet to follow for IBS.
But first, here are some nutritional information and explanations that can help you understand what works best for you.
Nutrition and other Terms You Need to Understand
There are a number of nutrition terms that can be confusing for many people, especially those many, many people who (unfortunately) decided early on that chemistry and nutrition science was not for them. Hang in there—it really is a lot less complicated than you might think.
Foods To Eat
Foods to Avoid
Best Supplements for IBS
- Fiber is a type of carbohydrate, primarily from plant sources. Fiber does not get digested (by you), so fiber does not increase blood sugar levels. Fiber can help regulate blood sugar and cholesterol levels and help maintain digestive regularity by moving material through your digestive system. In general, diets that are high in fiber are associated with a decreased risk of heart disease, diabetes, certain digestive disorders and constipation. It is not currently known with any degree of certainty, but fiber may also help decrease the risk of colon cancer and potentially other forms of cancer such as breast cancer.[1] Fiber is also necessary for maintaining a healthy (and essential) bacterial population in the large intestine. This bacterial population is known as the gut microbiome or the gut flora. These bacteria do digest fiber—and thereby provide us with nutrients known as short-chain fatty acids (SCFAs) such as butyrate that provide the cells in the intestine with an immediate fuel source.
- There are essentially two types of fiber—soluble and insoluble fiber.
- Soluble fiber dissolves in water. This is the type of fiber that helps maintain normal levels of blood sugar and cholesterol. Soluble fiber is a bit “gooey” and thickens your food as it passes through the digestive system. It also slows down the passage of food. Soluble fiber is found in oatmeal, beans, legumes such as lentils, nuts, apples and berries.
- Insoluble fiber cannot be dissolved in water and functions as bulk to move material through the intestines and help maintain regular bowel movements. Insoluble fiber is found in whole grains, brown rice, non-lentil legumes and vegetables including leafy green vegetables, carrots and tomatoes.
- While fiber can easily be divided into these two classes, it is not so easy in practice because most foods contain both soluble and insoluble fiber. Another way of describing fiber is to look at resistant starches versus non-resistant starches. Resistant starches resist digestion, but can be digested by the gut bacteria and produce SCFA. Resistant starch also helps maintain blood sugar and cholesterol levels. [2] Resistant starches are found in under-ripe bananas, oats, barley, beans, and lentils.
- Fiber is often recommended for both IBS with diarrhea and/or constipation. Why? Because they are often found in the same foods and because the soluble fiber can help thicken foods and slow digestion (relieving some cases of diarrhea) while the insoluble fiber also slows digestion and adds bulk to intestinal contents, either helping it move better (relieving constipation) or thickening it up (relieving diarrhea).
- FODMAPs: FODMAPs is the acronym for Fermentable Oligo-saccharides, Di-saccharides, Mono-saccharides And P These are a type of carbohydrate that are made up of short chains rather than the long chains generally found in fiber and starch. In general, these are poorly absorbed by the small intestine and provide the sort of fuel used by bacteria to make gas—a major cause of abdominal pain and discomfort. A low FODMAPs diet is gaining greater acceptance and may come closest to a recommended “IBS diet”.[3]
- Fermentable mainly means fluid and gas-producing in this context
- Oligosaccharides include fructans. Fructans are found in artichokes, asparagus, Brussel sprouts, beets, leeks, garlic and onions, grain such as wheat and rye. Oligosaccharides also include galactooligosaccharides (GOS). GOS are found in chickpeas (garbanzo beans), lentils, kidney beans and soy products like soy milk and tofu.
- The main disaccharide found in foods is lactose, primarily in cow’s milk and cow’s milk products such as yogurt, puddings, cheeses and ice cream.
- Monosaccharides covers fructose, the main sugar in fruit—and often added to many products in the form of high fructose corn syrup (HFCS). Fructose is also found in natural sweeteners such as honey and agave syrup.
- Polyols are found in fruits such as apples, apricots, blackberries, cherries, nectarines, pears, peaches, plums and watermelon; many vegetables (including cauliflower and snow peas) and in mushrooms. They are also found in popular sweeteners such as sorbitol, mannitol, xylitol, maltitol and isomalt.
- In a low FODMAPs diet, you don’t have to eliminate those foods (see “Elimination Diet” below), but you can limit the amounts that you eat. You have probably noticed that many of these foods are generally very healthy foods and provide much needed nutrition, but, mainly through a process of trial and error, you will be able to pinpoint those foods that may be more problematic for you than others.
- The foods to avoid in a low FODMAPs diet include those listed below.[4] The unavoidable fact is that you will spend a good deal of time peering at food labels—and you should be aware while labels have gotten better, you will need to “read into” some of these. This is why it is often recommended that you stick with whole, unprocessed foods—you don’t need to read THOSE labels! Another tip for reading labels is that the ingredients are listed in order—the first ingredient is in the highest concentration and the last is in the lowest concentration—if a high FODMAP food is listed as the last ingredient, it may still count as a low FODMAP food.
- Avoid any food or beverage with High Fructose Corn Syrup (HFCS). There is an extraordinary number of processed and prepared foods that contain HFCS from sauces, candies, canned foods and fast foods.
- Avoid any high-lactose dairy food such as milk, cheeses (and cheesy sauces), ice cream and sour cream. It also means avoiding products made from cow, goat or sheep milk.
- Cheeses that are allowed are hard cheeses such as cheddar, colby, parmesan, Swiss and soft cheeses such as brie, feta and mozzarella.
- Avoid soy products (eg tofu, miso) and soybeans
- Avoid beans, black eyed peas and lentils,
- Avoid cashews
- Allowed nuts include walnuts, macadamia nuts, peanuts, pecans and pine nuts
- Avoid wheat, barley and rye—use only gluten-free grains such as quinoa, millet, buckwheat, tapioca, potato, rice and amaranth
- Avoid fruits such as apples, apricots, berries (boysenberries, blackberries), figs, mango, guava, peaches, papaya, pears, plums, watermelon, prunes.
- Allowed fruits are bananas, cantaloupe, grapes, honeydew, kiwi, lemon, lime, mandarin, orange, passion fruit, pineapple, rhubarb and tangerines. Allowed berries are raspberries, strawberries, blueberries and cranberries.
- Avoid vegetables such as artichokes, cauliflower, mushrooms, snap peas, onions, garlic
- Allowed vegetables include: bell peppers, sprouts, cabbage, carrots, bok choy (Chinese cabbage), cucumbers, zucchini squash, green beans, leafy green vegetables (spinach, Swiss chard, mustard greens, collard greens, kale), eggplant, tomatoes, turnips, parsnips and winter squash.
- Avoid any artificial sweeteners with mannitol, sorbitol, xylitol or isomalt.
- Beverages: Coffee and tea can be a problem for those with IBS, depending to some extent on the type of IBS. Caffeine in either coffee or tea (both black and green) can stimulate bowel activity. Carbonated drinks can also cause problems because of the added gas. Milk alternatives such as almond, coconut, rice milks can be used by most people with IBS. Fruit juices (made from the low FODMAP fruit) and that old stand-by, water, are good alternatives as well.
- Most meat, such as beef, pork and poultry and most fish are low FODMAP foods.
- Food Sensitivities, Food Intolerances and Food Allergies: Food sensitivities and food intolerances are essentially interchangeable terms, but food allergies are quite a different term, although many people, physicians included, use them interchangeably. Some food sensitivities and all food allergies involve the immune system, but significantly different processes of the immune system—with significantly different results. Food allergies always involve a type of antibody, IgE. Food sensitivities may involve antibodies, but these are IgMs, IgAs or IgGs.
- Food sensitivities and intolerances may be due to a lack of an enzyme that digests food—lactose intolerance is a good example. Many people either completely lack the enzyme, lactase, that digests lactose, the sugar found in milk or have very low levels of lactase in the small intestine. The bacteria in the intestine, DO have lactase, but bacterial digestion leads to gases. Other people may not lack an enzyme, but when their bodies digest wheat and other products containing gluten, for example, their immune systems react to these digestive products.
- Many people with IBS either suspect or know they have food sensitivities. The most common ones are to lactose, gluten, casein (a protein found in milk and dairy products) and soy. Food allergies to peanuts, shellfish and tree nuts are common as well. Current research supports the idea that IBS may be, at least in part, a non-celiac disease sensitivity to wheat or gluten and FODMAP sensitivity.[5]
- Elimination Diets: In an elimination diet, considered the “gold standard” for detecting food sensitivities, you remove one food at a time and wait to see if your symptoms improve. There is no denying that this can be a long and pretty intensive project, but one that can be very worthwhile in the long run. The idea is to eliminate the food and wait at least 3-4 weeks. Some physicians recommend 6-8 weeks, but for most people 3-4 weeks will let them know that either they should keep that food out of their diet or, if there is no change in symptoms, it is not likely that that particular food is a problem.
- Start with keeping a diet diary. In the diet diary, list all foods and beverages you eat or drink during the day—but, importantly, keep track of your symptoms. Keep track of any abdominal pain or discomfort, bowel movements, headaches or any other symptom that appears.
- Don’t forget the sauces and dressings or spices and condiments you have on your foods
- Then, using your diet diary as a guide, eliminate the foods that may be causing your symptoms. You can also use the high and low FODMAPs given above to help guide your decisions on what foods to eliminate.
- It is generally recommended that you only eliminate one food at a time, rather than a food group. For example, it would NOT be recommended that you eliminate all fruit from your diet for 3-4 weeks! In this case, for example, you can use the FODMAPs to just eliminate those foods that are high FODMAP foods (eg. the apples, apricots, figs and blackberries etc).
- If there is a food that you eat every day, consider eliminating this food. It may not be easy, but just as the saying goes “common things happen commonly”, the common foods that you eat may, in fact, be part of the problem.
- Most elimination diets include the process of re-introduction, but this is generally to determine if, in fact you have a sensitivity to the food, or in the case of IBS, if the food is causing your symptoms. Re-introduction can make sense if you really need or want to know if that particular food is causing your symptoms. If you eliminate gluten or HFCS-containing foods (as an example) from your diet and find yourself feeling much better, do you really need that proof by re-introducing that food? On the other hand, if you have eliminated a lot of foods, you may want to re-introduce some foods, one at a time, to see if you can take that food in small amounts.
- Another approach to an elimination diet is to remove all the most common problem foods. You would, for example, eliminate for at least 3-4 weeks all citrus fruit, tomatoes, eggplant and white potatoes, along with wheat, corn, rye, oats and all gluten-containing foods. You would also eliminate all nuts, seeds, meats except for fish, turkey, lamb and wild game and all dairy products, condiments and sweeteners. If this is the approach you take, then re-introduction makes a good deal of sense. In this case, after the 3-4 week elimination period, you would re-introduce, as an example, wheat and gluten-containing products. Re-introduce for only one day—then keep track of any and all symptoms for 2-3 days. If you are free of any symptoms, you should be fine with gluten. If not, keep gluten out of your diet. After this 2-3 days monitoring period, you can re-introduce, for example, dairy products and, again, watch for any symptoms for 2-3 days. You can keep repeating this process of essentially trial and error and after some months, get a very good idea of which foods you can and which foods you can’t eat.
- Start with keeping a diet diary. In the diet diary, list all foods and beverages you eat or drink during the day—but, importantly, keep track of your symptoms. Keep track of any abdominal pain or discomfort, bowel movements, headaches or any other symptom that appears.
- There are essentially two types of fiber—soluble and insoluble fiber.
Don’t Go it Alone!
This is not an easy task. Get recommendations from your physician for a qualified nutritionist or dietician to help you find the best approach for you. There is no single “one size fits all” approach to diet and IBS—it can vary depending on the form of IBS you have and it can vary depending on a variety of factors including your personal food likes and dislikes, how much time and energy you have to give to the process of trial and error, for many women, it may vary based on where they are in their menstrual cycle. For nearly all, it will vary depending on your stress levels and your personal response to stress. Finding a good support group may be helpful as well. It is not an easy task, but it can be done—and can make a very significant difference in your life!
References
[1]. https://www.hsph.harvard.edu/nutritionsource/carbohydrates/fiber/
[2]. http://onlinelibrary.wiley.com/doi/10.1111/j.1467-3010.2005.00481.x/full
[3]. http://www.health.harvard.edu/diet-and-weight-loss/a-new-diet-to-manage-irritable-bowel-syndrome
[4]. https://stanfordhealthcare.org/content/dam/SHC/for-patients-component/programs-services/clinical-nutrition-services/docs/pdf-lowfodmapdiet.pdf