Dietary fiber improves glycemic control in type 2 diabetes, but its therapeutic role in pregnancy diabetes is unclear. We assessed the effect of dietary fiber on glycemia in women with diabetes in pregnancy.
Methods: We searched three databases (Cochrane Library, MEDLINE, Web of Science) to identify RCTs exploring the effect of dietary fiber, high fiber diets or fiber supplementation on fasting blood glucose (FBG), postprandial blood glucose (PBG), and requirement for insulin therapy in pregnant women with any type of diabetes. Data was pooled for each outcome, and we calculated Hedges’ g from standardised mean differences between groups to estimate effect size.
Results: Of 1,462 identified studies, data from 20 eligible trials containing 1,016 participants were pooled. On meta-analysis, a higher fiber intake was associated with reduced FBG (Hedges’ g= -1.11, 95%CI; -1.92, -3.0), PBG (Hedges’ g= -0.66, 95%CI; -1.17, -0.14), and requirement for insulin (logOR -1.43, 95%CI; -2.07, -0.78). There was significant heterogeneity for FBG and PBG (>90%), attributable to differences in Intervention type (DASH, Low GI, supplement; p<0.01) and study duration <4wks (for PBG: p=0.04; not for FBG). Studies were mostly scored as high risk of bias due to lack of blinding (Cochrane Risk of Bias Tool v.2.0).
Conclusion: High-quality dietary intervention studies in pregnancy are lacking. Our results suggest that high-fiber diets improve fasting and postprandial glycemia and reduce the likelihood of requiring insulin in women with diabetes in pregnancy.
D. Jones: None. A. Kyriakidou: None. L. Cooper: None. N. Atta: None. P. Tobolska: None. S. Smith: None. E. Turner: None. C.J. Petry: None. C.L. Meek: Research Support; Dexcom, Inc.
