How do I reduce the amount of storage my Email application data is taking up?

I’m using an LG Tribute phone (Virgin Mobile service). The default email app installed is synced with my Microsoft Outlook account. I only use this account for ticket confirmations, boarding passes and the like. However, recently I noticed it is taking up the following storage: Total: 635 MB App: 24.5 MB App (SD Card): 0 MB Data: 610 MB Data (SD Card): 0 MB Considering my phone only has 2 GB of storage, the above is a heavy price to pay. When I hit the “Clear Data” button, I get the message “All this app’s data will be deleted permanently. This includes all files, settings, accounts, databases, etc.” I don’t want to delete my account so I was wondering if there is any other way to slim down how much data my Email application is using?