Fixing email issue soon is important for every user. No matter what device you are using for emails, it is always important to know some troubleshoot steps for some crucial issues like content in Email. If your email content is not visible then you can follow these troubleshooting steps to fix problem.
Go to Settings -> Mail, Contacts, and Calendars ->
If you have running iOS 4 in your iPhone with 3G network, reset it by holding home and sleep buttons together until the Apple logo appears. If you are a iPhone 3GS or iPhone 4 users then double-click home button.
Now find the mail icon, touch, and hold it until red circle appears.
Now touch the mail icon and open it and you will have your message display properly.