Pregnancy outcomes with differences in grain consumption: a randomized controlled trial.

OBJECTIVES: Contemporary obstetrics has begun to appreciate the importance of diet in pregnancy, but guidelines are not based on robust data. The hypothesis that a whole grains diet improves pregnancy outcomes is tested in this study. We compared maternal and neonatal outcomes for a pregnancy diet containing 75% of total carbohydrates as refined grains with outcomes for a diet with 75% of total carbohydrates as whole grains. METHODS: This was a randomized interventional study in a clinic population over the last 4-7 months of normal pregnancy with extensive compliance measures. Besides obstetrical and neonatal outcomes, anthropometric measurements were done. In addition to food frequency questionnaires (FFQs), total plasma alkyl resorcinols, a unique quantitative measure of whole grains, were used as a measure of whole grain consumption. RESULTS: The data show effective compliance and no difference in outcomes between the diets with regard to maternal weight gain, birth weights, subcutaneous fat and glucose tolerance. CONCLUSIONS: Ensuring compliance to a proper pregnancy diet resulted in satisfactory weight gain and normal outcomes even when the proportion of whole grains consumed is only 25% of total carbohydrates.

A randomized controlled trial of the effects of whole grains versus refined grains diets on the microbiome in pregnancy.

Dietary whole grain consumption has been postulated to have metabolic benefits. The purpose of this study was to compare a pregnancy diet containing 75% of total carbohydrates as refined grains with a diet of 75% of total carbohydrates as whole grains for pregnancy outcomes and effects on the microbiome. Gestational weight gain, glucose tolerance and newborn outcomes were measured on 248 enrolled compliant women from whom a subset of 103 women consented to give 108 vaginal and 109 anal swabs. The data presented here are limited to the patients from whom the vaginal and anal swabs were obtained in order to study the microbiome. A microbiome-16SrRNA survey-was characterized in these samples. Samples and measurements were obtained at the first obstetrical visit, before beginning a prescribed diet (T1-baseline) and after 17-32 weeks on the prescribed diet (T3). Food frequency questionnaires and total plasma alkylresorcinols were used as a measure of whole grain consumption. There were no dietary differences in maternal weight gain, birth weight, or glucose tolerance test. Mothers consuming the whole grains diet showed a trend of gestational decrease in vaginal bacterial alpha diversity, with increasing Lactobacillus-dominance. No significant difference was observed for the anal microbiome. The results suggest that diet modulations of the vaginal microbiome during gestation may have important implications for maternal and neonatal health and in the intergenerational transfer of maternal microbiome. Trial registration: ClinicalTrials.gov Identifier: NCT03232762.