Comparison of nutritional supplements for glycemic control in type 2 diabetes: A systematic review and network meta-analysis of randomized trials

source extracted confidence: high 2026-04-09
#adult #ascorbic-acid #bayes-theorem #blood-glucose #calcium

Comparison of nutritional supplements for glycemic control in type 2 diabetes: A systematic review and network meta-analysis of randomized trials

Kazemi et al., 2022 | Diabetes Res Clin Pract | Systematic Review

Citation

Kazemi Asma, Ryul Shim Sung, ... Soltanmohammadi Mozhgan. Comparison of nutritional supplements for glycemic control in type 2 diabetes: A systematic review and network meta-analysis of randomized trials. Diabetes Res Clin Pract. 2022-Sep;191:110037. doi:10.1016/j.diabres.2022.110037

Abstract

AIMS: Direct and indirect evidence were combined in this systematic-review and network meta-analysis (NMA) to assess and compare the effect of nutritional supplements on glycemic control, and rank the supplements accordingly. METHODS: PubMed, Scopus, and Web of Science were searched up to April 2021. We included randomized controlled trials that investigated the effect of vitamins D, C, and E, magnesium, zinc, calcium, selenium, and omega-3 on at least one glycemic marker, including glycated hemoglobin (HbA1c), fasting blood sugar (FBS), homeostasis model assessment-estimated insulin resistance (HOMA-IR), HOMA-B, and insulin, in adults with type 2 diabetes. To estimate effectiveness of supplements, a random-effects NMA in the Bayesian framework was applied. To assess risk of bias, Cochrane Collaboration Tool was used. RESULTS: Analysis of 178 studies indicated that zinc, vitamin D, omega-3, vitamin C, and vitamin E were effective in reducing HbA1c with low certainty. For reduction of FBS, zinc, vitamin D, and vitamin C, and for HOMA-IR, vitamin D were effective with low certainty. None of the supplements were effective in the reduction of insulin and HOMA-B with low certainty. After excluding poor-quality studies, only vitamin D was significantly effective in reducing all of the markers. Consistently, when the analysis was restricted to studies with a duration of ≥12-weeks, vitamin D reduced HbA1c, FBS, and HOMA-IR. CONCLUSIONS: Vitamin D supplementation was more effective compared to other supplements in improving HbA1c, FBS, and HOMA-IR, albeit with low certainty of evidence. This result was confirmed by low-risk of bias studies. REGISTRATION: CRD42021240691.

Key Findings

Analysis of 178 studies indicated that zinc, vitamin D, omega-3, vitamin C, and vitamin E were effective in reducing HbA1c with low certainty. For reduction of FBS, zinc, vitamin D, and vitamin C, and for HOMA-IR, vitamin D were effective with low certainty. None of the supplements were effective in the reduction of insulin and HOMA-B with low certainty. After excluding poor-quality studies, only vitamin D was significantly effective in reducing all of the markers. Consistently, when the analysi

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 178
Age Range See abstract
Condition diabetes

MeSH Terms

  • Adult
  • Ascorbic Acid
  • Bayes Theorem
  • Blood Glucose
  • Calcium
  • Diabetes Mellitus, Type 2
  • Dietary Supplements
  • Glycated Hemoglobin
  • Glycemic Control
  • Humans
  • Insulin
  • Magnesium
  • Randomized Controlled Trials as Topic
  • Selenium
  • Vitamin D
  • Vitamin E
  • Vitamins
  • Zinc

Evidence Classification

  • Level: Systematic Review
  • Publication Types: Comparative Study, Journal Article, Systematic Review, Network Meta-Analysis
  • Vertical: vitamin-c

Provenance

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