Effects of water-soluble vitamins on glycemic control and insulin resistance in adult type 2 diabetes: an umbrella review of meta-analyses.

Background and Objectives: Growing evidence has explored the effects of water-soluble vitamins supplementation on glycemic control and insulin resistance in diabetic patients; however, the results of previous meta-analyses are inconsistent. To address this, we conducted an umbrella review to synthesize the evidence on these effects. Methods and Study Design: A systematic literature search in Web of science, PubMed, and Cochrane Database of Systematic Reviews was performed from 2012 to November 2022. he quality of the meta-analyses was assessed using AMSTAR-2 and GRADE. Results: Fourteen systematic reviews and meta-analyses met the inclusion criteria, examining the effects of five water-soluble vitamins (B-1, B-3, biotin, B-9, and C) on glycemic control and insulin resistance. The findings suggest that vitamin C supplementation can improve glycemic control in type 2 diabetes, as indicated by reduced FBG and HbA1c, with more significant effects observed for durations longer than 30 days. Conclusions: Insulin resistance is improved by folic acid supplementations. More well-designed individual randomized controlled trials are needed in the future, as well as meta-analysis of higher quality. [ABSTRACT FROM AUTHOR]