title: Proportions of A1, A2, B and C β-casein protein variants in retail milk in the UK.
abstract: The A1 variant protein of the β-casein family has been implicated in various disease states although much evidence is weak or contradictory. The primary objective was to measure, for the first time, the proportions of the key β-casein variant proteins in UK retail milk over the course of one year. In total, 55 samples of semi-skimmed milk were purchased from five supermarkets over the course of a year and the proportions of the A1, A2, B and C casein variant proteins were measured, using high resolution HPLC-MS. The results showed that β-casein in UK retail milk comprises approximately 0.58, 0.31, 0.07 and 0.03 A2, A1, B and C protein variants, respectively. The proportion of A2 is higher than some early studies would predict although the reasons for this and any implications for health are unclear.
authors.affiliation: Food Production and Quality Division, School of Agriculture, Policy and Development, University of Reading, Reading RG6 6AR, United Kingdom. d.i.givens@reading.ac.uk
authors.forename: Ian
authors.initials: I
authors.lastname: Givens
authors.forename: Patricia
authors.initials: P
authors.lastname: Aikman
authors.forename: Trevor
authors.initials: T
authors.lastname: Gibson
authors.forename: Ronald
authors.initials: R
authors.lastname: Brown
mesh_terms: D000818:Animals; D002364:Caseins / Q000032:analysis*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D008892:Milk / Q000737:chemistry* / Q000191:economics; D006113:United Kingdom
chemical_list: D002364:Caseins