The Association between Maternal Dietary Protein Intake and Risk of Gestational Diabetes Mellitus

The amount and type of dietary protein affect glucose metabolism. However, the association between dietary protein intake and gestational diabetes mellitus (GDM) risk is vague. We examined this association. Methods: We included 152 GDM and 168 non-GDM participants (total 320), age 18-45 years from Arash Women's Hospital, Tehran, Iran. Protein intake was ascertained from 168-item Food Frequency Questionnaire at 24-40 weeks' gestation. GDM was defined as fasting blood sugar >95 mg/dL and/or oral glucose tolerance test >155 mg/dL. Dietary data were assessed using N4 software and statistical analysis was performed using SPSS 21. We tested the association between the amount of protein consumed from red and processed meat, poultry, dairy, egg, seafood, and vegetable plus sociodemographic and lifestyle covariates and GDM risk using multivariate logistic regression analysis.

There was a significant association between the physical activity (P < 0.035), socioeconomic status (P < 0.013), body mass index, age, and each trimester's weight (P < 0.001), and risk of GDM. No significant association was observed between the intake of protein from major protein sources and risk of GDM. The only significant association was observed for egg consumption which was lower in GDM participants (P = 0.004), yet this association turned nonsignificant after adjustment for confounders, except for the fourth quartile (odds ratio: 0.43, 95% confidence interval: 0.208, 0.893).

According to our findings, dietary intake of total and major protein sources could not affect the GDM risk. Differences between Iranian and Western population and the reverse causality might be the main reasons for this nonsignificant association.