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Review
. 2017 May 15;7(5):e274.
doi: 10.1038/nutd.2017.16.

A1 Beta-Casein Milk Protein and Other Environmental Pre-Disposing Factors for Type 1 Diabetes

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Free PMC article
Review

A1 Beta-Casein Milk Protein and Other Environmental Pre-Disposing Factors for Type 1 Diabetes

J S J Chia et al. Nutr Diabetes. .
Free PMC article

Abstract

Globally type 1 diabetes incidence is increasing. It is widely accepted that the pathophysiology of type 1 diabetes is influenced by environmental factors in people with specific human leukocyte antigen haplotypes. We propose that a complex interplay between dietary triggers, permissive gut factors and potentially other influencing factors underpins disease progression. We present evidence that A1 β-casein cows' milk protein is a primary causal trigger of type 1 diabetes in individuals with genetic risk factors. Permissive gut factors (for example, aberrant mucosal immunity), intervene by impacting the gut's environment and the mucosal barrier. Various influencing factors (for example, breastfeeding duration, exposure to other dietary triggers and vitamin D) modify the impact of triggers and permissive gut factors on disease. The power of the dominant trigger and permissive gut factors on disease is influenced by timing, magnitude and/or duration of exposure. Within this framework, removal of a dominant dietary trigger may profoundly affect type 1 diabetes incidence. We present epidemiological, animal-based, in vitro and theoretical evidence for A1 β-casein and its β-casomorphin-7 derivative as dominant causal triggers of type 1 diabetes. The effects of ordinary milk containing A1 and A2 β-casein and milk containing only the A2 β-casein warrant comparison in prospective trials.

Conflict of interest statement

SK is a former employee of The a2 Milk Company (Australia) Pty Ltd. KW has previously (2013) undertaken scientific consulting unrelated to this paper for The a2 Milk Company. KMD has received research grants from The a2 Milk Company and on one occasion received a speaker fee from The a2 Milk Company (Australia) Pty Ltd. All other authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Proposed model for progression to type 1 diabetes in genetically susceptible people.
Figure 2
Figure 2
Structures of A1 and A2 β-casein. Adapted from Pal et al.
Figure 3
Figure 3
Correlation between A1 β-casein supply per capita in 1990 and type 1 diabetes incidence (1990–1994) in children aged 0–14 years in 19 countries. (r=0.92; 95% confidence interval: 0.72–0.97; P<0.0001). Dotted lines are the 95% confidence limits of the regression line. Reproduced with permission from R Elliott and The New Zealand Medical Journal (2003).

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