You could either save the messages to a file and then remove the headers you don't want, or 'print' the messages to a text file with only 'significant headers' (where you define significant as only the Subject).  Either way is not exactly simple but may do what you need.

Is there a way to export messages such that the Subject as well as the body of the messge is included?

 My brother needs a program that can automatically parse a few thousand email messages into "Subject" and "Body" fields. No other part of the message is important to him.

 Thanks in advance for any help,

    Rich