Save the theme for sharing, extract the *.theme file and edit it.
YourTheme.deskthemepack -> YourTheme.theme, add the following:
Look here for details:
TitleText=255 255 255
InactiveTitleText=255 255 255
Windows 8 Desktop UI - Change Title Text Color?
With the given settings above, the File Explorer titles cannot be changed only those of other programs if you use a standard Aero theme.
For the changes to take effect globally you'll need to use a high contrast theme.
Special Themes (AeroLite and High Contrast variations)