Hi to everyone who might be interested in my daughter's progress since I started this thread around five and a half years' ago. It's now June 2019 and I'm delighted to say that her life has turned around completely.
She stuck to her policy of eating a 'no sugar' diet for about four years and was very strict about this. It included no alcohol, which was extremely difficult as it basically alienated her from friends. No potatoes or anything that the body converts to sugar. She didn't eat wheat/gluten or dairy products either because these can be difficult for the digestive system. No caffeine, but enjoyed herb teas and just good quality water (not tap water unless it's filtered). She took a combination of really high quality probiotics, combined with natural antibiotics, natural anti-inflammatory products and other gut-healing products. Some of these were difficult for her system to cope with and she had to have tiny doses of certain ones, gradually building up to higher doses. She did have guidance for the first three years and eventually continued along the same path herself, rotating the products every few weeks so that her system didn't get too used to them.
The most difficult thing along the way was the attitude of other people. They mainly felt that she should just go to the doctor and endure all the rather invasive tests. Few of them were interested enough to learn that even if IC or similar bladder conditions are diagnosed (a loose term, diagnosis as it's really just an 'umbrella' condition rather than a specific medical condition), there's not much that could be done anyway. And possibly the investigations would make things feel worse for the sufferer.
She also went to a kinesiologist and had Vega-testing. This was heartening and not meant to be diagnostic in terms of a specific condition, but just for her (us) to be reassured that we were on the right sort of path. You go down this health-boosting route without really knowing if it's going to help. Both of these people, mentioned above, came up with similar results - that she was intolerant as soon as they tested for anything containing sugar (honey, sucrose, etc).
It seemed that she just needed to take everything back to basics in order to allow the gut to heal the body. Our immune system is in the gut. Nature wants us to heal, but many products stop this process from happening. Candida (yeast) tends to grow out of control if it gets the chance and it feeds off sugar. Once the natural immune system has been disrupted (often through the over-use of antibiotics), it needs to be re-built.
Gradually, she felt better. It was slow and steady. Some days she felt worse than others but she has now put it all behind her and says she doesn't even want to think about it. We don't mention IC any more, hurrah!
Her diet is now completely normal. She makes sure she has leafy green vegetables regularly and is always aware (mentally) when her diet hasn't been very good. However, she eats absolutely anything. She has friends again and no longer feels the odd one out.
I do believe this has made her into a stronger person and she is certainly empathetic for people who have health conditions, particularly those that are invisible to the naked eye.
I'm really proud that she endured this horrible condition, stuck to her beliefs, even when people were mocking her, and came through the other side. She managed to achieve a 1st Class English degree along the way and now works full time. She certainly found out who her friends were, as some stuck by her, even when the going was tough.
If you are reading this, you are probably suffering too. I wrote this update when another reader of the thread asked me to do so.
My message to you all is not to give up. Try not to be downhearted when things feel so awful. Try to understand what this condition could be caused by - I'm sure everyone is different but something in your history must point towards why it started. Don't expect a quick fix. Don't cheat if you decide to change your diet - there's no point in cutting out sugar if you give yourself a day off here and there. Your time for celebrating with champagne and chocolates will come!