Relations of dietary type of protein, glutamine, and glutamate to the incidence of type 2 diabetes mellitus among middle‐aged women

Objective: To examine the relations of types of protein, glutamine, and glutamate to the incidence of diabetes (T2DM) among middle‐aged women. Methods: We identified incident cases of T2DM among 70,356 nurses free of T2DM and major chronic diseases at baseline, 1984–2002. Dietary habits were assessed using food frequency questionnaires. Cox proportional hazard models were used. Risk was considered significant at p for trend value<0.05. Results: During the 18‐years follow‐up (1,115,620 person‐years), we documented 3,804 new cases of T2DM. After adjusting for demographic and lifestyle variables, T2DM was not associated with total protein RR=0.88[0.78;1.00], p =0.14), animal protein (RR=0.96[0.85;1.09], p =0.77), and glutamate (RR=0.88[0.77;1.00], p =0.10). Although plant protein was inversely associated with T2DM in the multivariate model (RR=0.88 [0.78;1.00], p =0.03), this relationship appeared to be explained by cereal fiber (RR=0.97[0.85;1.11], p =0.64).Glutamine was also inversely associated with T2DM in the multivariate model (RR=0.81[0.72;0.91], p <0.001). In further analysis, glutamine was inversely related to T2DM independent of cereal fiber (RR=0.87 [0.77;0.99], p =0.02) and total protein (RR=0.79 [0.69;0.90], p =0.0002). Conclusions: Study findings suggest a significant modest inverse relation of glutamine with T2DM independent of total protein.