Type I (insulin-dependent) diabetes mellitus and cow milk: casein variant consumption

Previously published Type I (insulin-dependent) diabetes mellitus incidence in 0 to 14-year-old children from 10 countries or areas was compared with the national annual cow milk protein consumption. Countries which were sele cted for study had appropriate milk protein polymorphism studies, herd bree d composition information and low dairy imports from other countries. Total protein consumption did not correlate with diabetes incidence (r = +0 .402), but consumption of the beta-casein A(1) variant did (r = + 0.726). E ven more pronounced was the relation between B-casein (A(1) + B) consumptio n and diabetes (r = + 0.982). These latter two cow caseins yield a bioactiv e peptide beta-casomorphin-7 after in vitro digestion with intestinal enzym es whereas the common A(2) variant or the corresponding human or goat casei ns do not. beta-casomorphin-7 has opioid properties including immunosuppression, which could account for the specificity of the relation between the consumption of some but not all beta-casein variants and diabetes incidence.