Irritable Bowel Syndrome (IBS) is considered a functional disorder, so there is no test for diagnosis. IBS includes a complex mixture of symptoms such as constipation, diarrhea and abdominal pain that is accompanied by periods of normal digestion. For this reason it can be difficult to determine what the triggers are.
IBS is different for everyone and some have reported that lactose, sorbitol, alcohol, caffeine, and dietary fat are triggers. Fortunately, many people have found relief with the low FODMAP diet. This diet limits foods that contain lactose, fructose, fructans, galactans and sugar alcohols. (1)
These sugars are not easily digested and thus can cause gas, bloating, constipation and diarrhea. Limiting these foods has shown in research studies to improve symptoms in 3 out of 4 participants. (2)
Begin by eliminating the FODMAP foods for 6-8 week and then one at a time reintroduce them into your diet. During this time it can be helpful to keep a food/symptom journal to truly determine triggers from non-triggers. Foods are typically categorized by high and low FODMAP foods, as seen in the table below adapted from Monash University. (3)
| Food Category | High FODMAP (avoid) | Low FODMAP (replace high foods with these) |
| Dairy | Any food made from cow, goat or sheep milk. | Lactose free milk, cheese, yogurt |
| Protein | Beans, legumes | Meat, fish, poultry, tofu |
| Nuts | Cashews, pistachios | Almonds, pumpkin seeds |
| Grains | Rye, wheat products | Rice, quinoa, gluten free products |
| Vegetables | Artichokes, onions, leeks, garlic, beets, cabbage, celery, corn, snap peas | Green beans, bok choy, bell peppers, carrots, chives, fresh herbs, cucumber, lettuce, tomato |
| Fruit | Apples, pears, mango, watermelon, nectarines, peaches, plums | Banana, orange, grapes |
If any of these foods are common to your diet and you are interested in trying the low FODMAP diet there are a variety of cook books and even phone apps that can provide you with a list of foods and recipe ideas, but for the expertise of navigating the complexities of changing nutritional habits, seek the guidance of a registered dietitian nutritionist. Get the support you need in making the low FODMAP diet work for you.
Just remember that these foods do contain nutrients essential to good health and nutritional deficiencies can occur if certain foods are cut from your diet completely, so you may need to supplement or find alternative nutrient sources.
