Here's a breakdown:

* Casein: The primary protein found in milk. It's actually a complex mixture of different proteins, but the main components are alpha-s1 casein, alpha-s2 casein, beta-casein, and kappa-casein.

* Sodium: A mineral that is added to the casein to form the salt, sodium caseinate.

So, the constituent elements of sodium caseinate are casein proteins and sodium.