show specific information to specific users in meteor dapp

Question

if a have a dapp with different users, and each user has his/her own profile page they can log in to. On this profile page, the user should be able to change/add his user information (name, age, etc) which should then be saved on the blockchain. The user should only have access to see and change his own individual information. How can that be done?.
Right now I'm able get the information on he blockchain in to the profile page and change it, but it is the same information/changes for every user. I'm using metamask and meteor.
Can anyone provide me with an example of how this could be done ? :)