IBS Diet

Diet, food and eating can affect symptoms in IBS. Many people with irritable bowel syndrome (IBS) notice that their symptoms appear to get worse following a meal. They may wonder if they have a dietary allergy or intolerance. More confusing, they may notice that a food seems to upset them on one day but not another. Among the most common questions IBS patients have is what food to avoid. This can drive a person to go looking for a diet or a test that might help sort all this out. A bewildering amount of often conflicting advice is available, especially on the Internet. Much of it is associated with a considerable cost.

Diet, eating, and IBS symptoms

There are a variety of factors that affect IBS, and diet is just one of these. If other factors, such as stressors or hormonal changes, are more active on a particular day, then diet is more likely to push your symptoms "over the edge."  

There is no evidence that digestion of food is different in those with IBS compared to those without IBS. Diet, food and eating does not cause IBS. However, increased intestinal muscle reactivity and/or heightened sensitivity in IBS can cause the bowel to over-respond to stimuli. Even a normal event such as the act of eating itself, and not a particular food, may aggravate symptoms at times. When we eat, hormones are released that stimulate the gut.

Cramping and diarrhea

Certain foods are known to stimulate gut reactions in general, and in those with IBS eating too much of these might influence or worsen symptoms. Examples that may provoke symptoms of abdominal cramps and diarrhea include:

• Meals that are too large or high in fat
• Fried foods
• Coffee
• Caffeine
• Alcohol 

Eating too much of some types of sugar that are poorly absorbed by the bowel can also cause cramping or diarrhea. Examples include: 

• Sorbitol – commonly used as a sweetener in many dietetic foods, candies, and gums
• Fructose – also used as a sweetener and found naturally in honey as well as some fruits

Gas and bloating

Some foods are gas producing (e.g., beans, cabbage, legumes [e.g., peas, peanuts, soybeans] , cauliflower, broccoli, lentils, Brussels sprouts, raisins, onions, bagels) and eating too much may cause increased gaseousness, particularly since IBS can be associated with retention of gas and bloating.

Fiber

If fiber seems to be a problem, it is usually insoluble fiber (mainly found in cereals or whole grains) that is the offender. Soluble fiber, mainly found in fruits and vegetables, is less likely to be a problem. When adding fiber to the diet, it is best to do so slowly over a period of weeks, which helps avoid discomfort. If gas or distention occur, try reducing the amount of fiber and reducing consumption of gas-producing foods. For more on dietary fiber Go ».

What to do about diet

The influence of diet is unique to each individual and there is no generalized dietary advice that will work for everyone. A physician can take a brief dietary history and with a 2-3 week diary of dietary intake, symptoms, and any associated factors (e.g., daily obligations, stressors, poor sleep, medications) can help identify dietary and/or other factors that may impact symptoms.

For those with IBS who benefit from simple dietary modifications, it makes sense to adjust the diet and reduce intake of the offending food. It does not make sense to adopt unnecessarily limited diets, which can lead to reduced quality of life or even malnutrition.

Physicians and patients need to talk about diet. Guidance needs to be provided by a knowledgeable health care professional (e.g., physician or registered dietician) who can assess individual circumstances while helping make sure that nutritional needs are being met through a balanced diet, and healthy eating habits.