Email alerts are managed in the main account profile area. Your profile can always be accessed via the link in the menu bar at the top right corner of any Portal page.
On your profile, click on the type of alert settings you would like to unsubscribe from (i.e. 'What's New in Healthy Aging', clinician, public health, health-system policymaker, social-system policymaker). Uncheck the "Enable email alerts" box at the top of the specific alert settings page for each of the alerts that you would like to unsubscribe from.
You may also unsubscribe by selecting 'unsubscribe' from the footer of any email alert.