Obesity status affects the relationship between protein intake and insulin sensitivity in late pregnancy

Authors: ALLMAN, BRITTANY - Arkansas Children'S Nutrition Research Center (ACNC); FUENTES, EVA DIAZ - Arkansas Children'S Nutrition Research Center (ACNC); WILLIAMS, D. KEITH - Arkansas Children'S Nutrition Research Center (ACNC); TURNER, DONALD - Arkansas Children'S Nutrition Research Center (ACNC); ANDRES, ALINE - Arkansas Children'S Nutrition Research Center (ACNC); BORSHEIM, ELISABET - Arkansas Children'S Nutrition Research Center (ACNC)

Submitted to: Nutrients
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2019
Publication Date: 9/11/2019
Citation: Allman, B.R., Fuentes, E., Williams, D., Turner, D.E., Andres, A., Borsheim, E. 2019. Obesity status affects the relationship between protein intake and insulin sensitivity in late pregnancy. Nutrients. 11(9):2190. https://doi.org/10.3390/nu11092190.
DOI: https://doi.org/10.3390/nu11092190

Interpretive Summary: There is an ongoing debate about the relationship between dietary protein intake and insulin sensitivity. Late pregnancy is characterized by an increase in both insulin resistance and the dietary protein requirement, the latter being of critical importance in order to satisfy protein requirements for adequate maternal and fetal tissue growth. However, it is not known if there are associations between amount and type of maternal dietary protein intake and maternal insulin sensitivity measures in late pregnancy. Therefore, the purpose of this study was to determine associations between the amount and type of protein intake and insulin sensitivity in late pregnancy. We determined the protein intake during pregnancy using diet records from women who participated in the Glowing study at Arkansas Children's Nutrition Center. Insulin sensitivity was determined from insulin and glucose concentrations in their blood at 30 weeks of pregnancy. We found that as the dietary intake of plant protein increased in the last trimester of pregnancy, insulin sensitivity also increased. However, this correlative relationship disappeared/weakened when accounting for early pregnancy obesity status. There was no relationship between animal protein intake and insulin sensitivity measures. Therefore, obesity status is a stronger predictor of insulin sensitivity than dietary protein intake in late pregnancy. We were able to clarify the relationship between maternal dietary protein intake (amount and type) and insulin sensitivity measures in late pregnancy, so that future research may better determine optimal protein requirements for adequate maternal and fetal tissue growth without compromising the metabolic health of the pregnant woman or her growing offspring.

Technical Abstract: The purpose of this study was to determine the associations between amount and type of dietary protein intake and insulin sensitivity in late pregnancy, in normal weight and overweight women (29.8 +/- 0.2 weeks gestation, n = 173). A 100-gram oral glucose tolerance test (OGTT) was administered following an overnight fast to estimate the metabolic clearance rate of glucose (MCR, mg/kg-1/min-1) using four different equations accounting for the availability of blood samples. Total (TP), animal (AP), and plant (PP) protein intakes were assessed using a 3-day food record. Two linear models with MCR as the response variable were fitted to the data to estimate the relationship of protein intake to insulin sensitivity either unadjusted or adjusted for early pregnancy body mass index (BMI) because of the potential of BMI to influence this relationship. There was a positive association between TP (B = 1.37, p = 0.002) and PP (B = 4.44, p < 0.001) intake in the last trimester of pregnancy and insulin sensitivity that weakened when accounting for early pregnancy BMI. However, there was no relationship between AP intake and insulin sensitivity (B = 0.95, p = 0.08). Therefore, early pregnancy BMI may be a better predictor of insulin sensitivity than dietary protein intake in late pregnancy.