Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder that affects around 15 percent of people in the United States. A functional gastrointestinal disorder is defined as one in which the GI tract doesn’t always work normally, but there are no discernible structural abnormalities. Similarly, when doctors administer any tests, the results typically come back as normal.
In 2015, “The American Journal of Gastroenterology” described a study in which researchers found differences between the gut bacteria of patients with irritable bowel syndrome and people with healthy digestive tracts. Some genera of bacteria are more common in patients with IBS and others are less common. The scientists speculated that differences in gut bacteria populations could affect a patient’s ability to digest certain foods.
Irritable Bowel Syndrome is twice as common in women as it is in men. Its symptoms can range from mild to severe, and they can include the following:
• Alternating constipation or diarrhea or both
• Pain in the abdomen
• Altered bowel habits
• Bloating and gas
• Feeling of fullness
There are many ways to treat irritable bowel syndrome, and they include lifestyle changes like getting regular exercise and managing stress. Modifying one’s diet is another treatment for IBS. This can be tricky, for different patients react differently to different foods. For example, foods with a lot of fiber can ease constipation in some patients but cause stomach pain or bloating in others. Given that, an IBS patient should keep a diary for a few weeks to help them identify foods or other possible triggers that cause or exacerbate their symptoms.
Some doctors recommend a low FODMAP diet for IBS patients. The acronym stands for Fermentable, Oligo-, Di, Monosaccharides, and Polyols. They all describe carbohydrates that are known to cause or worsen irritable bowel syndrome’s symptoms. Some of the 20 foods listed below are high in FODMAPs:
20 Foods That Can Worsen Irritable Bowel Symptoms
Alcohol is not digested in the same way as other foods; only 20 percent of it is absorbed by the stomach while the rest is absorbed by the small intestine. Alcohol can thus throw the digestive system out of whack. As the alcohol passes through the stomach, it causes the stomach to produce abnormally high amounts of stomach acid. The stomach is so busy producing acid it can’t ward off harmful bacteria, and some of those bacteria travel down the digestive tract. Similarly, alcohol can damage the mucous cells in the stomach and cause inflammation and lesions in the stomach lining.
2. Dairy products
Lactose intolerance is the inability to fully digest the carbohydrates in milk. Babies are born with the ability to produce an enzyme called lactase that enables them to metabolize lactose. As they get older, they often lose the ability to produce lactase and thus become lactose intolerant. In 2017, “The Lancet: Gastroenterology and Hepatology” published an analysis of multiple studies that demonstrated that the incidence of lactose intolerance varied by country. The researchers found that while around 67 percent of adults throughout the world are lactose intolerant, only 4 percent of the adults in Denmark are, while 100 percent of the adults in South Korea are lactose intolerant.
Dairy products like milk, cheese, and ice cream can cause symptoms like constipation, diarrhea, bloating, and cramps in patients who are lactose intolerant. A few cheeses have relatively low levels of lactose; examples include Parmesan, Mozzarella, Camembert, and Brie. The bacteria in yogurt break down the lactose in it, making it another possible option. IBS patients may also try lactose-free dairy products.
3. Fruits with pits
Fruits with pits like peaches and cherries often contain a lot of fructose, which is a monosaccharide and thus one of the FODMAP carbohydrates. Fructose can affect patients with IBS the same way that dairy products affect people who are lactose intolerant.
4. Other sources of fructose
Fruits with pits aren’t the only food items that contain a lot of fructose. Such items include the following:
• High-fructose corn syrup
Fortunately, there are fruits like bananas, oranges, and strawberries that are relatively low in fructose. In addition, some people have reported that eating fruit raw makes their symptoms worse. Conversely, cooking fruit may make it easier to digest.
5. Red meat
While red meat is a good source of nutrients like Vitamin B12, it’s also hard to digest. Poultry and fish are generally easier to digest.
Chocolate contains a variety of ingredients that can cause IBS. It contains caffeine, which is a diuretic and can thus make stools dryer and harder to pass. Chocolate cakes and bars are made with milk, and that can also cause constipation. Foods made with chocolate are also loaded with sugar.
7. Artificial Sweeteners
The science journal “Molecules,” however, described a study demonstrating how artificial sweeteners like sorbitol affect the digestive system. The researchers fed six types of artificial sweeteners to mice over a four-week period. The mice suffered such gastrointestinal ills as diarrhea and indigestion. The researchers found that the artificial sweeteners were actually poisonous to the mice’s gut bacteria. The artificial sweeteners also impaired the mice’s ability to metabolize glucose.
8. Fried and Fatty Foods
Fried food is bad for digestion, especially if it is also high in fat to start with. Fatty fried foods like French fries, chips, and certain cuts of meat, contain a lot of saturated fat, which the human body has trouble digesting. The body, therefore, has to produce more digestive enzymes and gastric acids than usual to properly digest it. Fried foods also disrupt the balance between the gut bacteria in the stomach. Since the body has to work extra hard to digest fried food, it can cause such unpleasant symptoms as indigestion, diarrhea, and nausea.
9. Processed food
More commonly known as junk food, processed food is bad for IBS patients in a lot of ways. It is often fatty, so it is hard to digest. It often contains artificial sweeteners and food additives. While the latter extend a food’s shelf life and make it look more appealing, many people have trouble metabolizing food additives.
Some people are sensitive or allergic to gluten, a substance found in wheat. Wheat also contains fructans, a type of carbohydrate related to fructose. Fructans are among the FODMAPs and are thus some of the carbohydrates that can trigger symptoms of irritable bowel syndrome, including diarrhea, bloating, stomach pain, and constipation. Unfortunately, wheat is also a good source of fiber, so people who need to avoid wheat will need to find other sources of fiber to keep their digestive tract working properly.
Rye is another source of fructans. As such, it can trigger symptoms of irritable bowel syndrome.
12. Carbonated drinks
Carbonated drinks like Coca-Cola, ginger ales, and soda water can all increase intestinal gas and cause bloating. Diet sodas are just as likely to cause gas as regular sodas, and they contain artificial sweeteners that can also cause problems. Regular sodas contain lots of sugar that can cause an imbalance in the gut bacteria, resulting in yet more gas.
13. Caffeinated drinks
Caffeine can cause diarrhea in some patients with irritable bowel syndrome, and it can worsen the dehydration caused by that diarrhea. Examples of drinks that can contain caffeine include coffee, tea, and some sodas. Some over-the-counter medications like the headache remedy Excedrin can also contain caffeine.
14. Cruciferous vegetables
Cruciferous vegetables are leafy green vegetables like kale, cauliflower, and Brussels sprouts. Many of them contain a sugar called raffinose that human beings can’t digest. Consequently, cruciferous vegetables are hard to digest and can cause diarrhea and/or constipation.
15. Other vegetables high in FODMAPs
Some vegetables contain a lot of FODMAP carbohydrates. Examples include the following:
Like fruit, raw vegetables are more likely to trigger symptoms than cooked vegetables. Vegetable juice may also be easier on the system.
16. Beans and legumes
Beans and legumes both contain carbohydrates that are hard for the body to properly digest. The gut bacteria ferment the undigested parts and thus cause intestinal gas. Examples of beans and legumes include the following:
• Baked beans
• Black-eyed peas
• Kidney beans
• Lima beans
Some patients can eat small amounts of canned chickpeas or lentils providing they have been carefully rinsed.
17. Chewing gum
Chewing gum often contains artificial sweeteners that make symptoms worse. Moreover, people often swallow air while chewing gum, and that can cause intestinal gas.
18. Spicy food
Spicy foods are often made with red chili peppers that contain a substance called capsaicin that can cause stomach pain and increase the GI tract’s motility. Capsaicin can cause abdominal pain and burning even in people who don’t have irritable bowel syndrome.
19. Foods with lots of fiber
Fiber is one of the more ambiguous items on the list. Some patients have found that it can relieve their symptoms, while others find it makes them worse. A large part of the problem is that there are several different types of fiber. Soluble fiber, for example, slows movement in the digestive tract, which can help people with diarrhea, while insoluble fiber has the opposite effect and can thus help people with constipation. Fibers can also be categorized by their viscosity and fermentability. In addition, eating too much of any fiber can increase bloating and gas. A patient who wants to increase their fiber consumption should do so gradually.
Corn contains a lot of fiber and sugar, and it is harder to digest than most vegetables. While processed foods should usually be avoided, IBS patients who love corn should consider foods like creamed corn or corn bran that are easier to digest.