How To Do An Elimination Diet


(By Bev Laumann) Many people with IC find that diet modification and an elimination diet are the most powerful tools they have to take control of their life and manage IC’s frustrating ups and downs. Soon after embarking on an IC diet though, most of us find truth in the old saying, “everyone’s different.” While the IC diet lists many foods to avoid, IC patients often find one or two “bad” foods that their bladder can tolerate. Or, they are surprised to find one or two “good” foods that others can tolerate, but they can’t. I’ve found I can eat a bit of watermelon or a few pecans now and then. Unfortunately, my IC friend Susan can’t touch even the tiniest bit of either. Yet she can eat bacon, and I can’t. Ralph can eat bananas all day, but Barbara’s bladder won’t tolerate them. And Meg says that foods don’t seem to effect her bladder one way or the other.

Dietary Differences

Why do we have these individual dietary differences? Doctors aren’t sure. One answer may be that IC is not one disease, but many. Different subsets of IC patients may have different causative factors for their bladder symptoms and this leads to differing experiences with food. The number of years one has had the disease and whether or not one’s bladder has “Hunner’s ulcers” may also be a factor in our food sensitivity. One study involving over 300 IC patients found that our sensitivity to spicy foods and tea increases with the number of years we’ve had bladder symptoms. The same study also found and that IC bladders with Hunner’s patches (also sometimes called “Hunner’s ulcers”) tend to be more sensitive to acidic and spicy foods than IC bladders without them.

Another possible explanation for our individual differences may be food intolerances or allergies. These food reactions may effect the bladder through the mechanism of bladder mast cells. In a recent broad-based survey involving thousands of IC patients, allergy (to food, airborne allergens, or medications) was found to be the most common IC-associated disease. More than 40% of those in the study had at least one allergy definitively diagnosed by a physician. According to a journal article on managing food allergy (S.C. Bischoff et al., in Allergy, 1995), “There is evidence that in subjects who are sensitized to foods, eating those foods alters their intestinal permeability and that this change in intestinal permeability allows an increased absorption of antigen. The symptoms and the severity of those symptoms at secondary target organs such as the skin or lung will be dependent upon the amount of antigen arriving at the target organs.” In other words, the irritating food substances pass through an unusually “leaky” intestinal lining and get into the blood stream, where they travel to a sensitized organ, and cause a painful reaction there. One could reasonably speculate that perhaps an IC bladder, already irritated and sensitized from other causes, may provide a target organ for this process in an allergic IC patient.

Many IC patients also have something called irritable bowel syndrome (IBS), a gastrointestinal condition that has also been linked to mast cells and increased intestinal permeability. Data from several studies have suggested that allergic reactions to food antigens may be a causative factor for at least some IBS patients.

Uncovering the Offending Foods

Whatever the medical reasons for our dietary problems and differences, as patients, we want as much control over our bladder symptoms as possible. We can do that by pinpointing which foods provoke our bladder. This may not be as easy as it first appears. Typical pin-prick allergy testing techniques will not uncover food sensitivities such as those IC patients have. What’s more, reliable tests for reactions to food additives (ie., monosodium glutamate) have yet to be developed. But there are some tests available that may be helpful, particularly if you know that you already have pollen or medication allergies. Known as RAST tests, ELISA tests, or cytotoxic tests, these blood tests for food allergies are now available through some, but not all allergists. If you have food allergies, this kind of test can not only pinpoint foods your body reacts to immediately, but can also identify foods that cause delayed reactions. (Immediate reactions appear in minutes to hours and are mediated by a substance called IgE, whereas delayed reactions are mediated in the body by IgG and can appear a day or so after ingesting the allergen.) In the past some doctors considered them unreliable, but the tests have gradually gained acceptance as physicians have seen the positive results with their allergy patients. Finding and eliminating food allergens may or may not be helpful in controlling your particular bladder symptoms though, and if you do see improvement, it may take several months to become apparent.

Food intolerances are not the same as food allergies. An intolerance is just a general term that means you get symptoms of some sort when you eat a particular food. Intolerances do not involve the same mechanisms as allergies. So your bladder may react to foods, but that reaction may not involve an allergic process at all. Doctors consider food allergy tests inappropriate or useless for diagnosing food intolerance problems that are not allergies. The tried-and-true (and least expensive) method for discovering if foods cause symptoms, remains the elimination diet. It will reliably uncover which foods cause you trouble regardless of the underlying biologic mechanism.

General Guidelines for Elimination Diets

Most elimination diets have two phases: the first phase, where foods are eliminated and symptoms will be reduced (if successful), and the second phase, where foods are gradually reintroduced while watching for the appearance of symptoms. The whole process may take months to complete. Keep in mind also, that you must pay attention to nutritional adequacy during these dietary manipulations, especially during the second phase. Rotate the food groups you test. Don’t spend weeks adding green vegetables one at a time to your diet, while neglecting meats, dairy, yellow vegetables and grains.

Throughout the time you are manipulating your diet (and for at least a week before starting your dietary changes), it is important to keep a symptom score diary. This will be time-consuming, I can tell you right now. But it is necessary to do it this way because your memory will play tricks on you. In fact, in a recent study involving more than 300 IC patients, researchers found that only about 60% of the IC patients could tell their doctor (within reasonable limits) how many times per day that they urinated. (The patients were first asked how often on average they urinated, then their real frequency was tested and recorded. Those with more severe cases were better at guessing their real frequency than those with milder cases).

Because many IC patients also have migraine headaches, irritable bowel syndrome, fibromyalgia, and other medical conditions, it is important to take note of the effect of diet on those symptoms also. Record each symptom separately, as each may be affected differently (or not effected at all) by your dietary experimentation. It is good to use a numeric severity scale (0-to-5 or 1-to-10, for instance) to rate your symptoms for the day. At the end of each day, record the numeric severity for frequency, urethral burning, backache, and fatigue separately.

Keep an open mind when embarking on an elimination diet, and watch for food additives. I remember one time I thought I couldn’t have sunflower seeds, because whenever I ate some, they bothered my bladder. As I continued to try the seeds again and again over a course of two weeks, my bladder’s reaction to them seemed to get progressively worse each time. When I went to throw out the empty jar, I noticed a white salty sediment remaining at the bottom. Suddenly it occurred to me that maybe it was something other than the seeds that caused the bladder pain. The label indicated that the seeds had added HVP (hydrolyzed vegetable protein). I figured that if the tiny amount of HVP was the real culprit, then maybe it would settle out in the jar and became more and more concentrated toward the bottom. That may expalin why my symptoms got worse each time I ate some seeds. I purchased some additive-free seeds later and they gave my bladder no problem. That experience taught me not to jump to conclusions.

Watch out also for ingredients that may not be on a food label. Sulfites, for instance, can be notorious IC pain-provokers, and are often problematic for allergic individuals too. By U.S. law sulfites must be on a food’s label only if the food contains more than 10 parts per million. (Lesser amounts and naturally occurring sulfites in non-packaged foods may provoke some IC bladders nonetheless.) Sulfites may be added to dried fruits, some processed potatoes, shrimp, and coconut. They naturally occur in wine and onions. The acidity of the food may increase the allergenic effect of the sulfite. Cooking can destroy or lessen some sulfite compounds, but if it is not completely destroyed you may still react to the remaining amount. (Baking, for instance, does not destroy enough of the sodium metabisulfite on coconut to keep my sulfite-sensitive bladder happy). It is best, for the purposes of an elimination diet, to work only with fresh foods that you know won’t confuse the issue with artificial additives. You can test additives separately later.

Watch out for certain words on packaged foods: “gluten” is wheat, “casein or caseinate” is dairy, “hydrolyzed” anything or “natural flavors” may have MSG, “surimi” contains fish, and “albumin” is egg white. One more thing to keep in mind when adding beef or other meats to your diet (as if there isn’t enough to remember) is that supermarkets sometimes illegally try to boost their profits by grinding up leftover pork, lamb and chicken trimmings with the ground beef. Pre-packaged ground turkey can also have MSG. When you wish to add meats to your diet, don’t use ground meats.

There are several kinds of elimination diets, and each person must evaluate for themselves which one is best suited for their particular situation. It is also a good idea to check with your doctor or consult a registered dietitian before embarking on any long-term dietary modifications. This is especially true if you have other serious medical conditions besides IC.

Elimination Diet Types

In general, there are three different types of elimination diets you can try (with appropriate review by your medical care provider). These are: (1) the simple exclusion diet, (2) the empirical diet, and (3) the few foods diet.

The Simple Exclusion Diet

The purpose of this diet is to firmly establish what the patient already suspects: that foods “A,” “B,” and “C” for instance, cause problems. This dietary tactic is easy to use and gives quick results. But it works best when your body’s reactions are quick, obvious, and severe, and when the number of suspect foods is not great.

One starts by totally eliminating suspect foods A, B, and C for a period of time, watching for symptoms to subside. (Often a week will suffice, and three weeks is probably the maximum needed for this “washout period”). If the symptoms subside, the foods are reintroduced one at a time. Suspect food “A” is reintroduced in a small amount the first day. Then, if symptoms don’t immediately worsen, continue to eat that food in normal amounts each day for a week. If symptoms return or become worse, eliminate food “A” for a “washout period” again before trying another food. The next week, try suspect food “B,” and so on.

Many of us with IC can identify a few foods that will provoke severe bladder symptoms in minutes, but some of our reactions take time to develop and are not so obvious. Therefore some substances may provoke bladders but we don’t even suspect them. Also complicating matters is the fact that emotional stress, exercise, environmental temperature, and other factors may play a role in the severity of our symptoms, making it difficult to identify whether or not a food is the problem.

Some of us feel we are sensitive to great numbers of foods but don’t really know which they really are. One newly diagnosed IC patient was so frustrated and confused by all her food sensitivities that she complained, “There’s nothing I can eat that doesn’t bother me! My bladder can’t seem to stand food in general.” If this describes you, another kind of elimination diet may work better at identifying your problem foods.

The Empirical Diet

The empirical elimination diet is used where a food intolerance is suspected, but the patient doesn’t have a good idea which particular foods are a problem. With this kind of diet one starts with a list of “usual suspects,” foods that other people with similar symptoms have found troublesome.

If you have IC, a good place to start is with the list of foods to avoid known as “the IC diet.” IC patients with allergies may add to the IC diet list some other commonly allergenic foods. (In the United States, the eight most common food allergies, in order of frequency are: egg, peanuts, milk, soy, nuts from trees, crustaceans, fish, and wheat. Corn, soy beans, citrus, melons, and chocolate may also be problematic). If you’ve been tested for food allergies, you might want to add those allergenic foods to the IC diet list.

Patients diagnosed with vulvodynia may add high-oxalate foods to the list of foods to avoid from the IC diet list. Spinach, wheat germ, citrus peels, green bell peppers, black pepper, and eggplant have been reported to be high in oxalates. For a listing of some other high-oxalate foods, see the “Low Oxalate Cookbook” published by the Vulvar Pain Foundation. Call for information (919) 226-0704, Tuesdays and Thursdays.

IC patients with irritable bowel syndrome (also sometimes called “spastic colon” ) may want to add fructose, high fructose corn syrup, sorbitol, and foods high in saturated fat (fatty beef ribs versus lean sirloin), to their list of foods to experiment with.

The procedure for the empirical diet is similar to the one for the simple exclusion diet in that all of the foods on the “suspect list” are withdrawn for a “washout period” of a week or so, then are gradually reintroduced one at a time while monitoring symptoms.

Empirical diets can have their problems. While the typical IC diet allows milk for instance, you may have a problem with it and not know it. Patrick is a newly diagnosed IC patient but has had various food and pollen allergies for many years. He is allergic to dairy products and the slightest amount will not only give him an allergic rash, it will also trigger an IC flare. Had he not already known about the milk, an empirical elimination diet based solely on the typical IC diet would not have detected his bladder’s milk sensitivity.

The Few Foods Diet

The few foods diet is the most drastic, but also the most likely to identify all of one’s problem foods. With this diet, the patient chooses a handful of foods that are the least likely to cause trouble, and eliminates everything but those to start with. Again, they will gradually add foods back into their diet, one at a time, while watching for a worsening of symptoms.

On this diet one must also watch for and eliminate additives in toothpastes, mouthwashes and non-food items. Vitamins and dietary supplements should be tested separately with the same care as other foods. Watch out for fillers and inert (inactive) ingredients in medications. (You can ask your pharmacist, or look up your medications’ inert ingredients in the Physician’s Desk Reference, which is often available at local city libraries). As with the other forms of elimination diets, one should maintain medications at an even daily level throughout the process. Test only fresh foods (not packaged) to avoid confusing the issue with additives (which may or may not be on the label).

Below are two slightly different versions of a few foods elimination diet that doctors use. Choose version A or B as your starting point. Start with the foods listed below. Eat only these relatively non-allergenic and IC-safe foods for a short period of time while symptoms subside (hopefully). Because this first phase is so restrictive one needs to be very careful to move quickly in adding foods, and to add foods from a variety of food groups. Such a restricted diet is nutritionally inadequate and at least one dietitian warns that three weeks of such drastic restriction is the most one should attempt as a “washout period” before beginning to add other foods. Some physicians are more conservative and recommend no more than ten days on such a restricted diet. Please consult your physician before you start this. He may have his own recommendation for the maximum number of days you should be on such restrictive fare for the “washout period”. Toward the end of the washout period, you might want to start a voiding diary writing down how you feel and how often you urinate. That will give you a baseline to compare things with when you begin adding foods back into your diet.

After the “washout period,” start adding foods back into your diet one at a time. When you start adding foods, add only a small amount of the food the first day. Then eat a normal or large amount of the food for another three or four days to give any delayed or dose-related reactions time to develop. Meanwhile, keep recording information in your voiding diary. If there’s any question as to whether the food made your bladder worse, compare it to how you were during the baseline “washout period.” (I used to think I my bladder didn’t have a problem with pecans because a few pecans sprinkled on pies or in cookies caused me no obvious and immediate increase in bladder pain. Then I sat down one night and ate a whole bag of them. Oh, did my bladder burn the next day!) Watch out for water too. You may want to test your local tap water as if it was a food. Some IC patients report having problems with very acidic tap water in their locale. (You can find out if your water is on the acid side by calling your local water district or water provider. If they give you acidity as a “pH” number, remember that numbers smaller than 7 are acid, and numbers larger than 7 are alkaline).

When you reintroduce foods like fruits and vegetables, be sure to test them both cooked and raw. For example, some IC patients report being able to tolerate cooked onions but not raw onions. You might have similar responses with other medical problems. In double-blind placebo-controlled testing of children with migraines, researchers found that foods such as apples, tomatoes and milk were problematic for some of these patients only in their uncooked state.

In true allergies, the allergenic substance in an offending food is usually a protein (such as egg albumin, for instance) and these proteins are typically still symptom-provoking after cooking. In a food intolerance (not a true allergy) however, the offending substance in the food is frequently not a protein and cooking doesn’t affect its ability to provoke symptoms.

Because you need to add foods very quickly to your diet after the washout period, concentrate on adding the foods that you’re least likely to react to first– leave the “problem” foods like chili or cranberry juice, for later. If you do experience a flare from a food, choose foods from your “safe” category and wait two or three days for your bladder to thoroughly calm down before trying to add another food.

Version A

  • Lamb
  • Turkey
  • Carrots
  • Parsnips
  • Rice
  • Rice flour
  • Pears
  • Sunflower oil
  • water (try Evian®)

Version B

  • Any one meat except chicken or veal
  • Carrots
  • Rice
  • Rice flour
  • Pears
  • Lettuce
  • Olive oil
  • Potatoes
  • water (try Evian®)

As a parting note, there is some evidence that true food allergies can be “outgrown” by children and that adults who modify their diet may lose their reactivity over time. This evidence stands in contrast to the evidence uncovered by IC researchers who find that some IC patients’ food sensitivities may get worse as the years go by. So while it is intriguing that IC patients have allergies, that antihistamines are effective for many IC patients, and that the foods we react to are also quite allergenic, it’s premature to assume that there is a real connection between food allergies and IC in all patients. Mast cells that inhabit the skin (where allergic rashes often occur) and mast cells that are in the bladder and intestinal tissue are different in many respects. There’s still a lot of research that needs to be done. In the meantime, diagnostic tools such as an elimination diet can help IC patients with very sensitive bladders figure out which foods bother them, and gain better control over their lives and well-being.


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  • * American Academy of Allergy, Asthma, and Immunology. Adverse reactions to Foods; 1995; 611 E. Wells St., Milwaukee, WI 53202-3889
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  • * Gallant, Stanley, M.D., Allergy-Endocrine Associates Medical Group. Elimination Diet. (patient educational material). 1987
  • * Gastaminza, G., Quirce, S., Torres, M., et al. Pickled onion-induced asthma: a model of sulfite-sensitive asthma? Clinical and Experimental Allergy 1995; Vol 25, pgs 698-703
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  • * Landis, J.R., and Kirstein, L.M. Agreement between patient-reported urinary frequency and frequency-volume charts in the national interstitial cystitis data base (ICDB) study. (abstract of presentation to the 1997 American Urological Association meeting, presented by Dr. Landis)
  • * Lessof, M.H. Reactions to food additives. Clinical and Experimental Allergy 1995; Vol. 25, supp. 1, pgs. 27-28
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Suggested Reading

  • A Taste of the Good Life: A Cookbook for an IC Diet by Beverly Laumann. Currently available in the ICN Shop!
  • The Best Guide to Allergy, Consumers Union Edition (by A. Giannin, N.D. Schultz, T.T. Chang & D.C. Wong) has an outstanding and comprehensive listing of food allergies, food groups & a variety of elimination diets.