The present disclosure provides a method for reducing the risk of autoimmune disease by administering a composition comprising peptides selected from a casein hydrolysate. Such a composition, may reduce the symptoms of autoimmune disease and may be a treatment for autoimmune disease, especially type 1 diabetes. Preferably, the hydrolysate consists of peptides with a molecular weight of more than 500 Da.本發明提供一種藉由投與包含選自酪蛋白水解物之胜肽的組成物以降低自體免疫疾病風險的方法。此組成物可減少自體免疫疾病之症狀且可為自體免疫疾病之治療,特別是第1型糖尿病。較佳地,該水解物由分子量大於500Da之胜肽所組成。