Sodium caseinate, also known as casein, is a protein derived from the milk that mammals produce. This protein is one of the main components of cheese, and is also added to various foods to change their flavors and consistencies, according to Livestrong.com.
Mammalian milk, such as milk from cows, goats and humans, contains casein. Some sources claim that sodium caseinate causes allergic reactions and can contribute to other medical problems, but research in this area has not produced conclusive evidence. The United States Food and Drug Administration provides information regarding the safety of sodium caseinate on its website, FDA.gov. The government agency has concluded that sodium caseinate is safe for consumption at appropriate levels.