The effects of folate supplementation on glucose metabolism and risk of type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

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#humans #blood-glucose #diabetes-mellitus-type-2 #dietary-supplements #folic-acid

The effects of folate supplementation on glucose metabolism and risk of type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Zhao et al., 2018 | Ann Epidemiol | Meta Analysis

Citation

Zhao Jie V, Schooling C Mary, Zhao Jia Xi. The effects of folate supplementation on glucose metabolism and risk of type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials. Ann Epidemiol. 2018-Apr;28(4):249-257.e1. doi:10.1016/j.annepidem.2018.02.001

Abstract

PURPOSE: Observationally, homocysteine is associated with higher risk of diabetes. Folate, which reduces homocysteine, is promising for the prevention and treatment of diabetes. Previous meta-analysis of three trials suggested folate might lower hemoglobin A1c (HbA1c). METHODS: An updated systematic review and meta-analysis of placebo-controlled randomized trials was conducted. We searched PubMed using ("folate" or "folic acid") and trial and ("glucose" or "diabetes" or "insulin" or "hemoglobin A1c" or "HbA1c") in any field until February 3, 2017. We also conducted a bibliographic search of selected studies and relevant reviews. Relative risk of diabetes and mean differences in indicators of glucose metabolism between folate and placebo were summarized in a meta-analysis using inverse variance weighting with random effects. Heterogeneity, publication bias, and risk of bias were also assessed. RESULTS: Eighteen trials of 21,081 people with/without diabetes were identified. Folate decreased fasting glucose (-0.15 mmol/L, 95% confidence interval [CI] -0.29 to -0.01), homeostatic model assessment-insulin resistance (-0.83, 95% CI -1.31 to -0.34), and insulin (-1.94 μIU/mL, 95% CI -3.28 to -0.61) but had no clear effect on diabetes or HbA1c. CONCLUSIONS: Our study suggests a potential benefit of folate on insulin resistance and glycemic control; the latter requires examination in more high-quality trials.

Key Findings

Eighteen trials of 21,081 people with/without diabetes were identified. Folate decreased fasting glucose (-0.15 mmol/L, 95% confidence interval [CI] -0.29 to -0.01), homeostatic model assessment-insulin resistance (-0.83, 95% CI -1.31 to -0.34), and insulin (-1.94 μIU/mL, 95% CI -3.28 to -0.61) but had no clear effect on diabetes or HbA1c.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 21081
Age Range See abstract
Condition diabetes

MeSH Terms

  • Humans
  • Blood Glucose
  • Diabetes Mellitus, Type 2
  • Dietary Supplements
  • Folic Acid
  • Glycated Hemoglobin
  • Hyperglycemia
  • Insulin
  • Insulin Resistance
  • Risk Factors
  • Randomized Controlled Trials as Topic

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Meta-Analysis, Systematic Review
  • Vertical: folate

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09