Human Health and Milk Proteins: The A1/A2 Milk Hypothesis

Abstract

Indigenous breeds of cows and buffaloes are of A2 milk type and hence are a source for safe milk. The A1/A2 status of cattle is determined by the two alleles for beta-casein gene i.e. A1 and A2 cattle may be homozygous for one type of protein (A1A1 or A2A2), or heterozygous (A1A2). A1A1 cattle would produce only A1 milk, A2A2 would produce only A2 milk and A1A2 cattle would produce milk with both A1 and A2 beta - caseins. NBAGR also reported moderate to high frequency of A2 allele among the breeding bulls, further supporting the belief that milk being sold in India is safe for human consumption. Considering the lack of concrete scientific evidence for A1/BCM-7 ill-effects on human health, and predominance of A2 milk in Indian cattle there is no need to move to A2 only.