Variation in consumption of cow milk proteins and lower incidence of Type 1 diabetes in Iceland vs the other 4 Nordic countries

Background: The incidence of Type 1 diabetes is lower in Iceland than in the other 4 Nordic Countries. Ealier studies have showed that the cow milk proteins A1 and B β-casein, suggested to be diabetogenic, are in lower amount in Icelandic cow milk than in milk from the other 4 Nordic Countries, and the per capita consumption of these proteins correlates with the incidence of Type 1 diabetes. Objective: To investigate whether lower consumption of the cow milk protein bovine serum albumin (BSA) (suggested to be diabetogenic) or higher consumption of immunoglobulin (Ig) or lactoferrin (LF) (suggested to be protective) is related to the lower incidence of Type 1 diabetes in Iceland. Methods: The per capita consumption of milk proteins was calculated from an international database on consumption of milk and milk products and from the analysis of cow's milk samples. The samples were randomly collected from the largest consumption areas in Iceland and in the other 4 Nordic Countries. Results: The per capita consumption of BSA was higher in Iceland (0.79±0.02 g/person per day) (mean±SEM) than in the other 4 Nordic Countries (0.43±0.05 g/person per day) (p=0.025). The per capita consumption of Ig was also higher in Iceland than in the other 4 Nordic Countries (p=0.025), while the consumption of LF was similar. Consumption of these 3 individual milk proteins did not correlate with the incidence of Type 1 diabetes in the 5 countries studied. Conclusion: Consumption of BSA, Ig or LF does not seem to explain the lower incidence of Type 1 diabetes in Iceland, compared with the other 4 Nordic Countries, while A1 and B β-casein may contribute to varying diabetogenicity of cow's milk and explain the difference in incidence of Type 1 diabetes.