• Journal of Dairy Science and Biotechnology
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• v.26 no.1
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• pp.11-19
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• 2008

Milk from dairy cows has long provided a high quality source of protein and selected micronutrients as calcuim to most populations. Recently, a relationship between disease risk and consumption of specific bovine ${\beta}$-casein fraction either A1 or A2 genetic variants has identified. Populations, which consume milk contain high containing high levels of ${\beta}$-casein A2 variants, have a lower incidence of cardiovascular disease and type 1 diabetes. Furthermore, consumption of milk with the A2 variants may be associated with less severe symptoms of autism and schizophrenia. The mechanism of action focuses on ${\beta}$-casein A1 and related forms preferentially that are able to produce a bioactive opioid peptide, ${\beta}$-casomorphin-7(${\beta}$-CM-7) during digestion. Infants may absorb ${\beta}$-CM-7 due to an immature gastrointestinal tract. Adult, on the other hand, appear to reap the biological activity locally on the intestinal brush boarder. ${\beta}$-CM-7 can potentially affect numerous opioid receptors in the nervous, endocrine, and immune system. Whether there is a definite health benefit to milk containing the A2 genetic variant is unknown and requires further investigation.