Mail items downloaded on iPhone 4 under iOS7.1.2

I have an 8 GB iPhone 4 running iOS 7.1.2 (I can't go to 8 as it is not supported on my phone).

Due to numerous positions I hold I have several business-related as well as personal email accounts active on the phone.

Back when I set the mail servers up I told it how many messages to download (I think this was using iOS 4 or 5) but I can't find this option any more. I would like to reduce the number of messages that are downloaded to reserve/conserve memory usage.

Does anyone know how to do this now?

Thank you.