I would recommend choosing your flavor (or flavour) of English and using that version in the same text. Since BrE and AmE words already have different meanings, you risk confusing your readers even more by using both words in the same text. Exceptions could be when the text is actually explaining the difference between the meanings, and also if you put the second word in parentheses, such as I did for 'flavor (flavour)', even though this is a spelling difference only.