While foods do not cause IBS, eating certain foods, called "trigger foods" may set off symptoms of diarrhea, bloating, or pain. Unfortunately, there is no one diet that will work for all people with IBS, but there are some guidelines that may help.
Eating several smaller meals during the day, rather than three large ones may help to reduce symptoms (large meals may result in cramping and diarrhea). Additionally, it may be helpful to keep meals low in fat and high in carbohydrates such as whole-grain breads, pasta, rice, fruits, vegetables, and cereals. A low fat, high protein diet may also help with pain experienced after eating.
Common trigger foods include:
- Artificial sweeteners or sugar substitutes
- Artificial fat (Olestra)
- Carbonated beverages
- Coconut milk
- Coffee (even decaffeinated)
- Egg yolks
- Fried Foods
- Poultry skin and dark meat
- Red meat
- Solid Chocolate
Soluble fiber has several benefits that may also reduce symptoms of IBS. Fiber may prevent spasms because it keeps the colon somewhat distended. It also absorbs water, which helps to keep stools from being too hard and therefore difficult to pass. Initially switching to a high fiber diet may increase gas and bloating, but these symptoms should decrease in a few weeks as the body adjusts.
Foods high in soluble fiber include:
- Brown rice
- Dried beans
- French bread
- Fresh peas
- Methylcellulose (Citrucel)
- Oat Bran
- Psyllium husks (Metamucil)
- Sourdough bread
Supplements may be helpful in adding the necessary fiber to the diet. There are three main types of soluble fiber supplements (psyllium, methylcellulose, and polycarbophil) and each has varying uses, side effects, and properties.
Psyllium can be taken every day to bulk up stool, making it easier to pass. It works by breaking down in the gut and becoming a food source for the "good bacteria" there but it does contain calories and may cause gas.
Methylcellulose is a fiber that is nonallergenic, non-fermentable, can be taken every day and is created from the cell wall of plants. It is not absorbed by the intestinal tract but instead absorbs water to create a softer stool. Because it does not ferment it is less likely to cause intestinal gas.
Similar to methylcellulose, polycarbophil is created from plants and is not absorbed by the body. It absorbs water in the intestinal tract and creates a bulkier and softer stool. Polycarbophil is less likely to cause bloating and can be used long term.
Reducing intake of foods that cause intestinal gas may help in decreasing bloating. Chewing gum increases gas in the body, as does swallowing air while eating (which can occur when gulping liquids or talking while eating). Carbonated beverages (such as soda pop or sparkling water) can also lead to bloating and intestinal gas (as well as belching).
Foods that may cause gas
- Brussels sprouts
People with IBS have digestive tracts that are more responsive to stimuli, therefore foods or additives may cause incapacitating symptoms, while only causing mild symptoms in other people. Some people with IBS may also have food sensitivities. Food sensitivity is different than a true food allergy, so it may not be detected in traditional allergy tests. Some of the more common causes of food sensitivity include:
- Sorbitol (a sugar substitute)
- Fructose (found in fruit juice and dried fruit)
- Lactose (found in milk)
- Wheat bran
Lactose intolerance is a common condition that is the result of the body's inability to digest lactose, or milk sugar. Symptoms include gas, bloating, and sometimes-even pain. If lactose intolerance is suspected, avoidance of milk and milk products (cheese, ice cream, and butter) should reduce symptoms. When milk products are reduced, care must be taken that enough calcium is added to the diet through either foods high in calcium, or a calcium supplement.