User updating + send message with only the modified values

Hello,

I want to send a mail with only the changed values of the user.
On the user profile I have several fields : phone, address, firstname, lastname...
Is there a solution to retrieve in my mail message only the new values ?

I tested a comparaison of datas in action, but it's useful if we have one or two fields. I have 15 / 20 fields. This is complexe...

Perhaps I can make this with a php code ?

Thanks for your help.