If the detect tables does not work, another possibility is that layout tables are causing you grief so make sure they are turned off.
Web sites have CSS in order to put text into columns and other cute layouts, but Mail generally ignores CSS functions for complex layout so designers end up using tables with multi row or multi column spans that can not effectively be read column by column row by row, so the screen reader ends up either reading things repetitively or else skipping important information.
  
Sometimes the mail will have a plain text alternative either in the same message or in a subscribe button. This of course brings its own problems.