If you are unsure as to which foods aggravate your symptoms, it is worth trying a two-week “elimination diet” followed by food challenge. This involves removing the high-risk foods listed above, for two weeks and keeping a daily log of your IC symptoms on a 1 to 5 scale. There will hopefully be an improvement.
It is important to substitute other foods from the same group (e.g. cottage cheese for yoghurt), to keep a healthy balance. After two weeks reintroduce the food, by itself, and wait to see if there is a reaction. If not, add a further portion to your next meal and bring the food back into your diet. One food should be brought back every 3 days, to allow for a delayed reaction, and food types should be rotated (e.g. day 1 cheddar, day 4 tomatoes).
If the food provokes symptoms, avoid the food, and rechallenge at a later date. You still need to record symptoms on a scale of 1 –5 to review progress, and to uncover any unsuspected food trigger. Remember that other factors such as stress can make symptoms worse.
This method requires discipline and planning, so make sure you have a food notebook and food alternatives at home before starting. You may find that you are able to tolerate cooked foods, but not raw, or that you have a sensitivity to some permitted foods (e.g. wheat, which can provoke other symptoms such as IBS). You need to be a good detective, and avoid foods whose ingredients you don’t know.
Once you start to avoid your individual trigger foods, you may need to consider extra vitamin and mineral supplementation. Make sure you use a good quality company (such as Solgar, Quest, Lamberts or Biocare) that produces hypoallergenic supplements.