Food Allergies and IBS

Could a Food Allergy Be Your Problem?

It is common to wonder whether a food allergy may be causing your IBS symptoms. The following information about food allergies and IBS may help you figure out what is going wrong and what you can do about it.

What is a food allergy?

A person is considered to have a food allergy when their immune system reacts to a food substance that is normally considered harmless. This immune response triggers the release of chemicals that cause a variety of symptoms. Some of these symptoms may be gastrointestinal in nature, including vomiting, diarrhea and/or abdominal pain. It is also possible that the person will experience symptoms more commonly associated with allergies, such as hives, itching, swelling of the lips, tightness in the throat, and difficulty breathing.

What is the relationship between food allergies and IBS?

Traditionally, true food allergies have been considered to be rare. However, some research suggests that reactions to certain foods may account for some IBS symptoms. More importantly, the studies suggest that by eliminating exposure to those foods, IBS symptoms will diminish. A major criticism of this research may be made in that food allergies were diagnosed in study participants based on the presence of a substance in their blood called Immunologlobulin G (IgG). IgGs are antibodies produced by the immune system to fight infection, but are not considered reliable for the purpose of diagnosing food allergies. Since the studies did show a reduction of symptoms through the use of an elimination diet, it is still worth taking a look:

• The most common foods identified as being problematic were milk, eggs, wheat, beef, pork, and lamb.
• Elimination diets resulted in a reduction of overall IBS symptoms, frequency of pain, and abdominal bloating.
• Elimination diets resulted in an improvement in quality of life, sense of control over IBS, and improved functioning of the rectum.
• Most patients showed a good ability to stick with the restricted diet.
• Patients who demonstrated better compliance to the restricted diet experienced the greater amount of improvement.
• Cheating on the diet resulted in a worsening of symptoms.

One study sought to try to discriminate among organic GI disorders, IBS and food allergies based on the symptom picture. Results indicated that IBS is more likely to involve straining, diarrhea and abdominal bloating than organic disease. Organic disease is more likely to involve loss of appetite and upper abdominal reflux difficulties. When symptoms in IBS patients were compared to those in patients with food allergies, IBS was more likely to manifest itself as pain in the lower abdomen, pain relieved by having a bowel movement, more frequent pain, and abdominal bloating.

How do you know if you have a food allergy?

There are a variety of diagnostic tests that your doctor may recommend to determine if you have a food allergy. It is also helpful to keep a food diary to look to see if there are any patterns in terms of what you eat and the symptoms you experience. Once a food is identified as a potential allergen, an elimination diet is used to assess whether or not symptoms decrease in the absence of that particular food. If symptoms don't improve, you can slowly re-introduce the food to your diet.

_Sources:

Atkinson, W., Sheldon, T., Shaath, N. & Whorwell, P. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut 2004 53:1459-1464.

Drisko, J., Bischoff, B., Hall, M. & McCallum, R. Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics. Journal of the American College of Nutrition 2006 25:514-522.

Neri, M. et.al. “Symptoms discriminate irritable bowel syndrome from organic gastrointestinal diseases and food allergy.” European Journal of Gastroenterology and Hepatology 2000 12:981-988.

Practice Parameters for Allergy Diagnostic Testing.

Zar, S., Mincher, L., Benson, M. & Kumar, D. Food-specific IgG4 antibody-guided exclusion diet improves symptoms and rectal compliance in irritable bowel syndrome. Scandinavian Journal of Gastroenterology 2005 40:800-807.