To ensure that there is no extra formatting occurring you should take a look at the data that is in the db. If there is any extra formatting here you should be able to see it.
If there is no extra characters or formatting present in your db or on the pages in your site then it would indicate that the problem is how Outlook is rendering the characters in the message.
You can also test this out by sending a message to a web based email account to see if the characters show in there.
Please report back and let us know what you discover, if it is only outlook that is rendering the characters differently then you may need to adjust the encoding that Outlook is using.