Some evidence indicates that the immune system, which fights infection, is also involved. Irritable Bowel Syndrome symptoms result from the following: The normal motility of the colon may not work properly. It can be spasmodic or can even stop temporarily. Spasms are sudden strong muscle contractions that come and go.

The lining of the colon (epithelium), which is affected by the immune and nervous systems, regulates the passage of fluids in and out of the colon. In Irritable Bowel Syndrome, the epithelium appears to work properly. However, fast movement of the colon’s contents can overcome the absorptive capacity of the colon. The result is too much fluid in the stool. In other patients, colonic movement is too slow, too much fluid is absorbed, and constipation develops.

The colon responds strongly to stimuli (for example, foods or stress) that would not bother most people.

In people with Irritable Bowel Syndrome, stress and emotions can strongly affect the colon. It has many nerves that connect it to the brain. Like the heart and the lungs, the colon is partly controlled by the autonomic nervous system, which has been proven to respond to stress. For example, when you are frightened, your heart beats faster, your blood pressure may go up, or you may gasp. The colon responds to stress also. It may contract too much or too little. It may absorb too much water or too little.
Research has shown that very mild or hidden (occult) celiac disease is present in a smaller group of people with symptoms that mimic Irritable Bowel Syndrome. People with celiac disease cannot digest gluten, which is present in wheat, rye, barley, and possibly oats. Foods containing gluten are toxic to these people, and their immune system responds by damaging the small intestine. A blood test can determine whether celiac disease is present. (For information about celiac disease, see the Celiac Disease fact sheet from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).)

The following have been associated with a worsening of Irritable Bowel Syndrome symptoms:

• Large meals
• Bloating from gas in the colon
• Medicines
• Wheat, rye, barley, chocolate, milk products, or alcohol
• Drinks with caffeine, such as coffee, tea, or colas
• Stress, conflict, or emotional upsets

Researchers have also found that women with Irritable Bowel Syndrome may have more symptoms during their menstrual periods, suggesting that reproductive hormones can exacerbate Irritable Bowel Syndrome problems.

Irritable Bowel Syndrome affects more than twice as many women as men, for reasons that are not yet understood.

IBS is a physical — not psychological — disorder characterized by lower abdominal pain (spasms or cramps) or discomfort, diarrhea, constipation (or alternating diarrhea & constipation), gas, bloating, and nausea. There is no cure for Irritable Bowel Syndrome, which is actually a brain-gut dysfunction, but there are many very effective ways of controlling and even eliminating IBS symptoms through safe Irritable Bowel Syndrome treatments.

Irritable Bowel Syndrome Symptoms – What Are They? How is IBS Diagnosed?
It’s important to verify that your symptoms match those of Irritable Bowel Syndrome before you accept this diagnosis. As noted, IBS is characterized by continuous or recurrent lower abdominal pain or cramping (from mild to excruciating) in association with altered bowel motility (diarrhea, constipation, or both). Attacks may strike suddenly at any time of day or night, and may occasionally — though not typically — wake you from a sound sleep. Gas and bloating are common, but vomiting isn’t, though it can occur due to nausea from the pain. Upper GI symptoms are not a typical part of Irritable Bowel Syndrome. For women, attacks are often associated with menstruation. Passing blood, running a fever, swollen extremities, and joint pain are not symptoms of IBS, and point to other disorders. IBS is diagnosed in part by the use of the official diagnostic criteria known as the Rome II Guidelines for Irritable Bowel Syndrome.

Irritable Bowel Syndrome Diagnosis? These Diseases Must Be Ruled Out First!
In addition to verifying that your symptoms match those of the Rome II Guidelines, it’s also important that the following diseases are excluded before you accept a diagnosis of Irritable Bowel Syndrome:

As a rule, all possible physical, structural, and infectious abnormalities of the GI tract need to be unquestionably eliminated before you agree to an Irritable Bowel Syndrome diagnosis. This requires a physical examination, preferably by a board-certified gastroenterologist. The medical tests needed to rule out disorders other than IBS will depend upon your age, health history, family health background, and specific symptoms.

Once you have a firm IBS diagnosis, take heart. While there is no cure yet, there are many ways to successfully manage – and prevent – all Irritable Bowel Syndrome symptoms. You can control your IBS, not vice versa.

To start feeling better immediately, begin with the Irritable Bowel Syndrome diet and learn why how you eat is just as important as what you eat.