Whey Protein Premeal Lowers Postprandial Glucose Concentrations in Adults Compared with Water-The Effect of Timing, Dose, and Metabolic Status: a Systematic Review and Meta-analysis.

BACKGROUND: Serving whey protein before a meal in order to lower postprandial blood glucose concentrations is known as a premeal. The underlying mechanisms are only partly understood but may involve stimulation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and insulin secretion together with a slower gastric emptying rate. OBJECTIVES: The objective of this systematic review and meta-analysis was to review all randomized clinical trials investigating premeals with whey protein in comparison with a nonactive comparator (control) that evaluated plasma glucose, GLP-1, GIP, insulin, and/or gastric emptying rate. Secondary aims included subgroup analyses on the timing and dose of the premeal together with the metabolic state of the participants [lean, obese, and type 2 diabetes mellitus (T2DM)]. METHODS: We searched EMBASE, CENTRAL, PUBMED, and clinicaltrials.gov and found 16 randomized crossover trials with a total of 244 individuals. The last search was performed on 9 August, 2022. RESULTS: Whey protein premeals lowered peak glucose concentration by -1.4 mmol/L [-1.9 mmol/L; -0.9 mmol/L], and the area under the curve for glucose was -0.9 standard deviation (SD) [-1.2 SD; -0.6 SD] compared with controls (high certainty). In association with these findings, whey protein premeals elevated GLP-1 (low certainty) and peak insulin (high certainty) concentrations and slowed gastric emptying rate (high certainty) compared with controls. Subgroup analyses showed a more pronounced and prolonged glucose-lowering effect in individuals with T2DM compared with participants without T2DM. The available evidence did not elucidate the role of GIP. The protein dose used varied between 4 and 55 g, and meta-regression analysis showed that the protein dose correlated with the glucose-lowering effects. CONCLUSIONS: In conclusion, whey protein premeals lower postprandial blood glucose, reduce gastric emptying rate, and increase peak insulin. In addition, whey protein premeals may elevate plasma concentrations of GLP-1. Whey protein premeals may possess clinical potential, but the long-term effects await future clinical trials.

Vitamin D levels were significantly higher during and after lifestyle intervention in pregnancy: A randomized controlled trial.

INTRODUCTION: Vitamin D deficiency is common in pregnancy, especially in obese women. Lifestyle intervention could potentially result in higher levels of vitamin D. We therefore aimed to study the effect of lifestyle intervention during pregnancy on serum levels of 25-hydroxyvitamin D (25(OH)D). MATERIAL AND METHODS: A total of 360 obese women were randomized before gestational age 14 weeks to lifestyle intervention (diet and exercise) or routine clinical follow up (controls). Clinical outcomes and levels of 25(OH)D were determined three times: At gestational age 12-15 weeks (baseline), gestational age 28-30 weeks and 6 months postpartum. RESULTS: A total of 304 (84%) women completed the intervention study and 238 (66%) attended postpartum follow up. Vitamin D levels were similar in the two groups at baseline. At gestational age 28-30 weeks and 6 months postpartum, 25(OH)D levels were significantly higher in the intervention group than in controls (75.6 vs 66.8 nmol/L, P = 0.009) and (54.8 vs 43.1 nmol/L, P = 0.013), respectively. Concurrently, vitamin D deficiency (25-hydroxyvitamin D <50 nmol/L) was less frequent in the intervention group than in controls: 15 vs 25% (P = 0.038) at gestational age 28-30 and 45 vs 63% (P = 0.011) 6 months postpartum, respectively. CONCLUSIONS: Lifestyle intervention during pregnancy was associated with significantly increased vitamin D levels in late pregnancy and postpartum compared with controls.

Impact of type 1 diabetes and glycemic control on fetal aneuploidy biochemical markers.

OBJECTIVE: To determine the influence of type 1 diabetes mellitus (T1DM) on the first trimester serum markers of fetal aneuploidy; pregnancy-associated plasma protein-A (PAPP-A) and free beta subunit of human chorionic gonadotropin (free ß-hCG) and to evaluate the influence of glycemic control on these parameters in the pregnant diabetic women. DESIGN: Retrospective study. SETTING: Data were extracted from electronic obstetric and laboratory databases at two Danish University Hospitals. POPULATION: Based on 36 415 pregnancies without T1DM (non-T1DM) and 331 pregnancies with T1DM; ß-hCG and PAPP-A were obtained at 8+0 to 14+2 gestational weeks. METHODS: Medians for PAPP-A and free ß-hCG were generated and multiple of the normal gestation-specific median (MoM) values were calculated for each separate pregnancy. After adjustment for maternal weight, ethnicity and smoking status, MoM values were compared across the T1DM and non-T1DM groups, respectively. Additionally, the relationship between PAPP-A MoM and HgbA1C was examined in 348 T1DM pregnancies by Spearman's rank correlation. MAIN OUTCOME MEASURES. Difference in biochemical marker levels between T1DM and non-T1DM. RESULTS: PAPP-A was 0.86 MoM in T1DM pregnancies and 1.01 MoM in non-T1DM pregnancies, p < 0.0001. Conversely, free ß-hCG was not altered in T1DM pregnancies (T1DM 0.99 MoM, non-T1DM 0.98 MoM; p=0.14). There was a significant inverse correlation between HgbA1C and PAPP-A (rho=-0.12, p=0.02). CONCLUSIONS: In T1DM pregnancies, PAPP-A MoM values were lower than in non-T1DM pregnancies. This suggests that correction should be considered in first trimester biochemical screening for fetal aneuploidy in T1DM women.