Potential Protective Protein Components of Cow's Milk against Certain Tumor Entities

Abstract

Milk and dairy products, especially from cow's milk, play a major role in the daily human diet. It is therefore hardly surprising that the subject of milk is being extensively researched and that many effects of individual milk components have been characterized as a result. With the wealth of results available today, the influence of milk on the development of various types of cancer and, in particular, its often protective effects have been shown both in vitro and in vivo and in the evaluation of large-scale cohort and case-control studies. Various caseins, diverse whey proteins such as α-lactalbumin (α-LA), bovine α-lactalbumin made lethal to tumor cells (BAMLET), β-lactoglobulin (β-LG), or bovine serum albumin (BSA), and numerous milk fat components, such as conjugated linoleic acid (CLA), milk fat globule membrane (MFGM), or butyrate, as well as calcium and other protein components such as lactoferrin (Lf), lactoferricin (Lfcin), and casomorphines, show antitumor or cytotoxic effects on cells from different tumor entities. With regard to a balanced and health-promoting diet, milk consumption plays a major role in a global context. This work provides an overview of what is known about the antitumoral properties of proteins derived from cow's milk and their modes of action.

Keywords: antitumor peptides; antitumoral effects; cancer; cow’s milk; health-promoting diet.

Figure 1

Approximate composition of cow’s milk. Proteins are divided into insoluble casein proteins and soluble whey proteins [18].

Figure 2

Overview of the insoluble casein proteins and their share in the total casein fraction. The green box indicates some important processed peptide variants after casein digestion. Some of them are α-amides, methyl esters or have free α-carboxyl groups [20,21,22].

Figure 3

Overview of the soluble whey proteins and their share in the total protein fraction. The green box indicates some processed peptide variants after whey protein digestion. Some of them are α-amides, methyl esters or have free α-carboxyl groups [20,23].