Casein, from the Latin word "caseus" or cheese, is the predominant phosphoprotein accounting for nearly 80% of proteins in milk and cheese.

Casein has a molecular structure that is extremely similar to that of gluten. Therefore, most gluten-free diets are combined with casein-free diets and referred to as a gluten-free, casein-free diet.

References

Dalgleish, D. G. 1998. Casein micelles as colloids. Surface structures and stabilities. J. Dairy Sci. 81:3013–3018.