by Heather Van Vorous
Excerpted from Eating for IBS and The First Year IBS, copyright Heather Van Vorous
To the happy surprise of many IBS patients, there are specific guidelines for dietary changes that can help prevent all Irritable Bowel Syndrome symptoms. Unlike medications for IBS, which are keyed to specific symptoms, the same diet can help diarrhea and constipation both, as well as painful abdominal spasms and bloating.
The foundation of the proper Irritable Bowel Syndrome diet is soluble fiber. Why is soluble fiber so crucial? Unlike any other food category, it soothes and regulates the digestive tract, stabilizes the intestinal contractions resulting from the gastrocolic reflex (which go awry in people with IBS due to a brain-bowel miscommunication), and normalizes bowel function from either extreme. This means it regulates both over-motility and under-motility of the colon (people with IBS suffer from one or the other, or fluctuate between the two). As a result, soluble fiber prevents and relieves both diarrhea and constipation.
How is this possible? The "soluble" in soluble fiber means that it dissolves in water (though it is not digested). This allows it to absorb excess liquid in the colon, preventing diarrhea by forming a thick gel and adding a great deal of bulk as it passes intact through the gut. This gel (as opposed to a watery liquid) also keeps the GI muscles stretched gently around a full colon, giving those muscles something to easily "grip" during peristaltic contractions, thus preventing the rapid transit time and explosive bowel movements of diarrhea as well. By the same token, the full gel-filled colon (as opposed to a colon tightly clenched around dry, hard, impacted stools) provides the same "grip" during the muscle waves of constipation sufferers, allowing for an easier and faster transit time, and the passage of the thick wet gel also effectively relieves constipation by softening and pushing through impacted fecal matter. If you mentally picture your colon as a tube that is squeezing through matter via regular waves of contractions, it's easy to see how a colon filled with soluble fiber gel is beneficial for both sides of the Irritable Bowel Syndrome coin. Once you're stabilized soluble fiber will also help prevent further problems.
Both soluble fiber supplements (such as Acacia Tummy Fiber or Benefiber) and soluble fiber foods (like rice, pasta, oatmeal, potatoes, barley) will work for both diarrhea and constipation. In contrast, insoluble fiber (bran, raw fibrous vegetables, salad greens, unpeeled fruits) can trigger painful gastrointestinal spasms in Irritable Bowel Syndrome patients. These spasms can result in either urgent diarrhea or seize the colon muscles in a type of "charley horse", which then halts gut motility and exacerbates constipation. For this reason, the soluble fiber base is key, and insoluble fiber (which should absolutely be eaten) needs to be treated with care, and eaten according to Irritable Bowel Syndrome dietary guidelines.
Fats of all kinds are also triggers for constipation as well as diarrhea, because fats are a very powerful GI tract stimulant just like insoluble fiber. Fats can cause the same type of rapid spasms or "charley horse" muscle contractions in the colon, and again result in either diarrhea or constipation. The major Irritable Bowel Syndrome trigger foods - red meats, dairy, egg yolks, fried foods - are high in saturated fat and, for the meat, dairy, and egg yolks, also have proteins that are very difficult for the body to digest. Coffee (even decaffeinated) and alcohol are powerful GI tract irritants, and can have the same effects as fats and insoluble fibers.
In sum, the fundamental dietary guidelines for Irritable Bowel Syndrome are based on a high soluble fiber foundation, avoiding trigger foods, limiting fats, and incorporating insoluble fiber with care. These dietary changes can help prevent and alleviate the full range of IBS symptoms. Comprehensive dietary information is available at http://www.helpforibs.com/diet/ and there is a free Irritable Bowel Syndrome Diet Cheat Sheet downloadable on the site.
Heather Van Vorous is the author of Eating for IBS and The First Year IBS. She is the founder of http://www.helpforibs.com/ - the internet's largest IBS community. Her IBS dietary work has led to clinical research studies of diet and IBS, a nomination for a "Julia Child Cookbook" award, and her inclusion in the 4th edition of Who's Who in Medicine and Healthcare. Her Irritable Bowel Syndrome recipes have been licensed by Novartis pharmaceuticals and her products are recommended by physicians and dietitians across the world. Heather has had IBS since age 9.