Irritable bowel syndrome, or IBS, is one of the most common digestive issues in the U.S., but there's still a lot we don't understand about how it works or what exacerbates its symptoms. What we do know is that IBS is "a functional disorder of the gastrointestinal tract that is characterized by abdominal pain with an associated change in bowel habits," gastroenterologist Dr. Peyton Berookim tells Bustle. If you have IBS, he says, you're not alone: as many as 45 million adults in the U.S. have it. The symptoms of IBS aren't pleasant — they can severe stomach cramps and bloating, in addition to urgent feeligns of having to go to the bathroom — and it turns out that one of the biggest triggers of IBS issues is food intake. The body's digestive system needs to function properly to be able to break down various foods once they're ingested. For people with IBS, that system can go haywire. Various foods that are typically thought of as cornerstones of a nutritious diet, can in fact make IBS symptoms much worse because of their impact on the digestive tract. Here are 22 foods that you wouldn't expect can trigger IBS symptoms, despite their healthy pedigrees. 1. Apples Unfortunately, the king of the fruits is off the menu if you happen to have IBS, because it contains fruit sugars known as fructose, which are known to create issues in people with IBS, according to the Cleveland Clinic. 2. Pears The same issue with apples occurs with pears. Like other fruits that trigger IBS symptoms, they also feature a kind of sugar alcohol known as polyols. In people with IBS, nutritionist Dr. Robert Zembroski tells Bustle, the gut struggles to breakdown polyols. This leads to "abnormal motility characterized by increased gut contractions", and that causes IBS symptoms to worsen. 3. Cauliflower Cauliflower, like many other foods in the cruciferous vegetable category, is hard for people with IBS to digest, because it contains insoluble fiber — a kind of fiber that's hard to break down in the gut — and carbohydrates called raffinose, which can create issues for people with IBS when they're digested. 4. Beans Beans, Dr. Zembroski tells Bustle, "contain a protein called lectin, which can damage the intestinal wall, contributing to leaky gut and an aggravation of IBS." No baked beans on toast, then. 5. broccoli broccoli is on the same list as cauliflower for the exact same reasons — cruciferous vegetables contain insoluble fiber. broccoli and cheese soup is, alas, off the menu. 6. Chickpeas The problem with eating chickpeas, says Dr. Berookim, is their fiber, which people with IBS struggle to break down. "The high fiber content," he explains, "can produce gas and bloating and increase one’s discomfort." This may also mean that people with IBS can be sensitive to aquafaba, the liquid produced by chickpeas, which is often used as a replacement for egg white in vegan dishes. 7. Spices Spices don't have any complicated ingredients that might create problems for the gut to break down, but Dr. Zembroski advises against them anyway as they may exacerbate irritation in the digestive system. 8. Caffeine Caffeine, Dr. Berookim points out, is known to produce constipation because of its dehydrating effects — which is not a good idea when you have IBS, and could create or worsen symptoms. 9. Brussels Sprouts Brussels sprouts are, like cauliflower and broccoli, full of raffinose. The large intestine, Dr. Zembroski tells Bustle, breaks down raffinose through fermentation. In people with IBS, "this causes gas, flatulence, bloating, and pain." 10. Blackberries Blackberries are sweet, delicious — and not good for people with IBS. The reason? Fiber. "Dietary fiber has long been known to improve gut health, metabolic disturbances in the body, and be a superior fuel source for our gut bugs," Dr. Zembroski tells Bustle. However, in some people with IBS, "insoluble fiber can exacerbate symptoms of IBS from increased abdominal pain, bloating, and gut distention," he says. 11. Strawberries Strawberries and cream may be the best way to celebrate summer, but they're both a bad idea for people with IBS — the strawberries because their fiber might not be soluble, the cream because lactose products are known to be IBS triggers. In fact,lactose intolerance and IBS can look extremely similar. 12. Blueberries Unfortunately blueberries are in the category of fruits that might cause IBS symptoms, though they might be more soluble in water than others. 13. Coconut Coconut flesh is fibrous and, while tasty, offers a challenge to people with IBS whose digestive systems may struggle to deal with it without serious side effects, Dr. Zembroski tells Bustle. High levels of coconut water may also create issues for the gut. 14. Bran Yep, that healthy breakfast cereal can't be absorbed properly by a gut with IBS, even though it's healthier for most people than processed wheat or white bread. 15. High-Fat Foods "As a general rule, it is best to avoid items that will cause diarrhea," says Dr. Berookim, and adds that greasy foods are definitely in that category. 16. Chocolate Containing Dairy Dairy is known to cause diarrhea too, says Dr. Berookim, but it also has other issues for people with IBS. Items containing lactose, the milk sugar, are one of the most basic items that people with IBS should avoid, as lactose can cause serious problems in sensitive digestive systems. 17. Lentils Lentils are a source of insoluble fiber and can create issues with digestion that lead to all kinds of nasties for people with IBS, says Dr. Zembroski, including nausea and gas. 18. Yogurt This one may surprise you, as we've been told recently that fermented foods with live bacteria are great for the gut — but for people with IBS, those benefits are overriden by the presence of lactose and, as in many other dairy products like cheese, the protein casein. Both are difficult to process and can cause issues for people with IBS. 19. Mushrooms Unfortunately, mushrooms are one of the foods that are viewed as potential irritants to the gut in people with IBS, because of the presence of polyols. 20. Avocado The beloved feature of millions of brunch plates isn't a staple for people with IBS, because it has that old familiar foe: fiber. 21. Sauerkraut This is another case in which fermentation doesn't undo the damage that the original ingredients can cause. Sauerkraut is fermented cabbage, and while it's very fashionable at the moment, like kimchi (another no-no, because of its spiciness), people with IBS are advised to stay away from it because cabbage is a cruciferous vegetable and therefore difficult to process. 22. Red Meat Many people are trying to eat less red meat, whether for health or environmental reasons, but Dr. Berookim cites another reason that people with IBS should stay away from it: it's known to cause constipation. No, thank you. Making informed food choices, Dr. Zembroski tells Bustle, is hugely important for people with IBS. It could be the key to "relieving and perhaps preventing the symptoms of irritable bowel syndrome." However, IBS triggers are highly individual; some people can handle more of a certain kind of food than others. If you have IBS, talk to your doctor about what food choices can help your symptoms. Source