<<Disclaimer: Verify this information before applying it to your situation.>> In the Canadian Celiac Society survey (Campell et al. 1991. J. Canadian Dietetic Association 52:161-165), Table 2, which lists percentages of celiac patients who had symptoms from various foods, indicates that 11% of biopsy-proven celiac patients reported problems with white vinegar and 11% reported problems with citrus fruit. Almost everyone, celiac or not, has at least minor problems with some of the foods they eat. The immune system of the gut must deal with a great many foreign proteins, and other molecules, that we encounter through eating. It should not crank up any mechanisms that might harm our tissues when it encounters these food molecules (foreign to the body). At the same time, it must protect us from viruses, bacteria, and parasites, that we also take in through eating. Tissue damage can be an acceptable side effect when it comes to protecting the life of the organism against these invaders. The differences between food proteins and, say, viral coat proteins can be subtle. The complexity of the system is impressive and imperfectly understood at present. Sometimes the complexity works against us and causes reactions against food molecules. Breaks of the game. On the whole and with the vast majority of people, the system works well, but individual failures and breakdowns are not uncommon. Maize is another name for corn. Zein is the prolamin protein fraction of maize or corn. Zein is the maize equivalent of gliadin in wheat. I can't find the article or abstract right now, but if I recall correctly, researchers in the West of Ireland (Galway and nearby) found no significant association between celiac disease and schizophrenia. This does not prove that wheat ingestion has no association with the symptoms or origins of schizophrenia. Independent effects of wheat and wheat proteins-- with different mechanisms and resulting from different peptide sequences would not be ruled out. Donald D. Kasarda