On the iPhone lock screen, how can I see just the number of unread mails? As a Windows Phone user, I can see the number of new mails for an account on my lock screen. 

I'd like to have the same effect on my iPhone, without seeing the mail's preview content. Is there a way to do this without jailbreaking the phone? Note that I realize I can have mails in my notifications area, but that involves seeing a mail preview.
Settings, Notifications, Mail.

Change "Show Previews" (all the way at the bottom) to off.