Irritable Bowel Syndrome Treatment

I have suffered intestinal problems for years finally diagnosed by a 'functional' doctor as dairy intolerance. A friend finally convinced me to try taking straight lemon juice from two smaller, greener lemons from Mexico and it has cured my problem almost immediately. Apparently I also cannot handle soy as I had a bad reaction to Chinese food. I have been treated by normal MDs and none have ever diagnosed this dairy intolerance, they only treated the symptoms and never identified the cause.