A1 milk and beta-casomorphin-7

Abstract

Milk is composed of water, proteins, lipids, lactose, vit-amins, and minerals. More than 80% of most mam-mals’ milk proteins are con-stituted by caseins. Casein is a group of proteins and they are sub-divided into αs1-, αs2-, β- and -casein families. Among these ca-sein families, -casein is the second most abundant pro-tein. Different mutations in the cow milk -casein gene led to 12 genetic variants and most common of these are genetic variants A1 and A2. The A1 and A2 variants differ only at amino acid position 67, which is histi-dine in A1 or proline in A2 milk. This difference in amino acid sequence sug-gests a conformational change in the secondary structure of the expressed β-casein. Milk that contains A1 β-casein and A2 β-casein are known as A1 milk and A2 milk, respectively. A1 β-casein milk releases an amino acid bioactive pep-tide called beta-casomorphin-7 (CM-7) in small intestine. Beta-casomorphin-7 released from A1 β-casein is respon-sible for many human dis-orders like type-1 diabetes, autism, schizophrenia, alz-heimer’s disease (AD), at-tention deficit hyperactivity disorder (ADHD), multiple sclerosis (MS) and heart diseases.