Dietary fiber intakes and insulin requirements in pregnant women with type 1 diabetes.

OBJECTIVE

To determine whether higher dietary fiber intake (water soluble and insoluble) is associated with lower insulin requirements and better glycemic control in pregnant women with type 1 diabetes consuming a self-selected diet.

DESIGN

A longitudinal, observational study.

SUBJECTS

Pregnant women (n=141) with type 1 diabetes participating in an interdisciplinary program examining the effects of glycemic control on pregnancy outcome (Diabetes and Pregnancy Program, University of Cincinnati Medical Center).

MEASUREMENTS

We determined total, water soluble and insoluble fiber intakes from 3-day food records kept each trimester during pregnancy. Outcome measures were insulin dose, pre-meal blood glucose, and glycated hemoglobin concentrations.

STATISTICAL ANALYSES

Correlation coefficients, multiple regression, mixed-model analysis of variance.

RESULTS

Mean intakes (g/day) of total, water soluble fiber, and insoluble fiber were 14.0 (range, 1.8-33.1), 4.8 (range, 0.6-10.5) and 9.0 (range, 1.1-24.0), respectively. In the second and third trimesters of pregnancy, insulin requirements were inversely associated with total, water soluble, and insoluble fiber intakes; the correlation coefficients ranged from -0.22 to -0.17 (P=.02 to .08). Insulin requirements associated with a higher fiber intake (20.5 g/day) were 16% to 18% lower than for a lower fiber intake (8.1 g/day). These relations remained after adjustment for body weight, disease severity and duration, insulin type, and study year in the second (P=.03 to .10) but not in the third trimester. Pre-meal blood glucose and glycated hemoglobin concentrations were not associated with fiber intake.

CONCLUSIONS

Among pregnant women with type 1 diabetes, higher fiber intake is associated with lower daily insulin requirements. Dietary fiber intake should be considered when counseling patients about the management of blood glucose concentrations.