Effects of 12 nutritional interventions on type 2 diabetes: a systematic review with network meta-analysis of randomized trials

Numerous trials confirm dietary interventions benefit type 2 diabetes mellitus (T2DM) management, but the optimal model is unclear. We evaluated 12 interventions through a Network Meta-Analysis (NMA) on their effects on Fasting Plasma Glucose (FPG), 2-h Postprandial Glucose (2hPG), HbA1c, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), Total Cholesterol (TC), Triglycerides (TG), and BMI, providing evidence to guide clinical nursing. We conducted an NMA of randomized controlled trials (RCTs) (PROSPERO registration: CRD42023429616), searching eight databases for studies published between January 1, 2010, and August 31, 2024. Two reviewers independently screened studies, extracted data, and assessed bias using the Cochrane Risk of Bias tool. Key and important outcomes were analyzed using Stata 17.0, with evidence quality assessed via the Grading of Recommendations Assessment, Development and Evaluation (GRADE) and Confidence in Network Meta-Analysis (CINeMA) scores. Eighteen RCTs comprising 1,687 patients were included. Among 12 evaluated dietary interventions, MNT ranked highest in reducing FPG (SUCRA = 77.6%; SMD = -0.75; 95% CI: -0.88 to -0.61). Digital dietary models were most effective for reducing HbA1c (SUCRA = 84.6%; SMD = -1.06; 95% CI: -2.11 to -0.01), while LGI diets were superior for both 2hPG (SUCRA = 62.1%; SMD = -0.62; 95% CI: -0.76 to -0.47) and HOMA-IR (SUCRA = 96.9%; SMD = -10.13; 95% CI: -15.96 to -4.30). The LGI + LGL intervention was most effective in reducing TC (SUCRA = 88.3%), TG (SUCRA = 80.6%), and BMI (SUCRA = 99.8%), with statistically significant differences observed in pairwise comparisons (P < 0.05). The quality of evidence was rated as high for FPG, 2hPG, HbA1c, and BMI, and moderate for HOMA-IR, TC, and TG. These findings highlight the potential of MNT, LGI, digital dietary models, and LGI + LGL interventions to improve glycemic control and metabolic outcomes in patients with T2DM. However, further large-scale, multicenter RCTs are warranted to validate their long-term efficacy and safety. CRD42023429616.