Deborah,
That is one thing that I had not considered. However, I have always eaten lots of yoghurt and drank moderate amounts of milk to go with my cereal. I didn't use to eat cheese cause it is so fatty. Now I have cut out milk and yoghurt and started eating more cheese (up to 2-3 ounces a day).
Perhaps my body isn't used to the cheese but it is definitely used to the lactose. I will experiment with reducing cheese intake and keep my eye out for an improvement in symptoms.
Thanks!