Milk protein IgG and IgA: the association with milk-induced gastrointestinal symptoms in adults

Abstract

Subjects drinking milk (n= 45) had higher levels of milk protein IgG in their sera than non-milk drinkers (n=125, P<0.001). Subjects with gastrointestinal problems related to milk drinking consumed less milk but had higher milk protein IgG levels than those with no milk-related gastrointestinal symptoms (P=0.03). Among the symptomatic subjects, those reporting dyspeptic symptoms had lower milk protein IgG levels than nondyspeptics (P<0.05). However, dyspepsia was not associated with milk drinking (P=0.59). The association of high milk protein IgG levels with constipation was close to the level of statistical significance. Diarrhea had no association with milk protein IgG level (P=0.5). With regard to minor symptoms, flatulence and bloating (P=0.92), were not associated with milk protein IgG level. Milk protein IgA levels did not show any association with milk drinking or abdominal symptoms. The levels of milk protein IgA and IgG declined as the age of the subjects increased (P<0.001). Conclusion Milk protein IgG but not milk IgA seems to be associated with self-reported milk-induced gastrointestinal symptoms.