A composition comprising(a) milk or a crude protein-containing extract thereof；(b) a fatty acid or a lipid or a salt thereof； and(c) an acidifying agent in an amount that is sufficient to reduce the pH of the composition to less than 4；wherein the composition has been heat-treated.Compositions of the invention have biological activity in particular in the treatment or prevention of gastrointestinal cancer, and so use as nutraceuticals or pharmaceuticals.
