Folic Acid as a Potential Vitamin in Glycemic Control: A Systematic Review

Purpose: This systematic review aims to examine the relationship between serum folate level and folic acid supplements with glycemic control parameters (fasting blood glucose (FBG), insulin level, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and Hemoglobin A1C (HbA1c)) in adult individuals with current studies. Methods: In this study, which was designed as a systematic review, the searches were performed on Web of Science, Science Direct, Medline, Wiley, and Cochrane Library databases between April 10, 2023, and May 10, 2023, and the searches were updated between October 16, 2023, and November 14, 2023. Of the 1855 studies obtained from the screening, 17 met the criteria and were included in the systematic review. The PROSPERO system registered the study protocol (ID: CRD42023472434). Recent Findings: Although no significant correlation was found between serum folate levels and glycemic control parameters in most of the cross-sectional studies included in this systematic review, most of the randomized controlled trials showed that glycemic control parameters (FBG, insulin, HOMA-IR) decreased significantly in the intervention group receiving folic acid supplementation compared to the control group. However, study durations were short, and HbA1c needed to be evaluated in most studies. This makes it difficult to get information about the long-term effects of folic acid supplementation. Summary: More comprehensive studies should be conducted to draw more precise conclusions about the relationship between folic acid levels and folic acid supplementation with glycemic control parameters.