Casein is a group of phosphoproteins[1]; proteins that are bound to substances containing phosphoric acid[2]; which are found in dairy[1]. It has a large number of commercial uses, and it due to the ubiquity of milk, and the high amount contained therein (it can form up to 80% of the protein found in cows’ milk), it is commonly found in foods, although it is also sometimes used as an additive in non-food products[1].

The word itself derives from the Latin word for cheese, ‘caseus[1], and indeed it is a major component thereof; the process of cheese making requiring the separation of the milk into solid casein proteins (curd) and fluid whey proteins, the former being the basis of cheese[3]. It has also however been used in such applications as plastics and paint, although synthetic alternatives have dented its place in the market[1].

Being as it is a milk protein, it, suffice to say, agitates those who suffer from milk protein allergies[1][4][5]; furthermore given its structural similarity to gluten, it is often indigestible by those who are gluten intolerant[7]. More broadly, the effects of Casein on health are open to debate. It is, of course, a good source of protein, and is popular as a supplement due to its molecular structure that allows for a continued slow release of nutrients[6]. It also however has its controversies; it has been posited that reducing the amount of casein and gluten can reduce the symptoms of autism in children, although this remains unproven and is, in fact, mostly dismissed by the scientific community[8][9]. It has also been seen to negate antioxidant effects; this too is open to some debate, with no general consensus on the matter[1]. On a related note however, it has been evidenced as reducing the efficacy of certain drugs[1]. Evidence also suggests that casein may be mildly addictive, likely as a result of milk’s biological function[10][11].

Casein is often used as a food additive; due to its thickening properties and resistance to coagulation, it can make a good stabiliser or emulsifier[12][13]. This has the problem of it being sometimes introduced into otherwise vegetarian products.

Moo Free does not use casein in its products, on account of their dairy free nature.