You can customize the page constituents use to update their profile to limit how much information can be updated and what text is displayed to the constituent. For example, you can only include email on this page and it will effectively function as an email address update form. To customize the user profile update page:
  1. Go to Setup > Standard Page Center. If you do not have this option available, please contact support or an advanced site administrator to make this change for you. 
  2. Next to "Constituent Profile (User Update)" click "Customize"
  3. In step 1a you can choose the wrapper to display on the page and any text you would like to appear at the top of the page.
  4. On step 1b check the box next to every constituent field you would like the user to be able to update. Fields that are not checked will not display at all.
  5. On step 1c check the box next to every field you would like to be required on this form.
  6. On step 1d you can choose any text you would like to appear at the bottom of the page.
To link to this page in an email or on the unsubscribe page, please refer to this solution.