Comparative effect of dietary interventions for depression and anxiety in patients with elevated cardiometabolic risk: a network meta-analysis of randomized controlled trials

Depression and anxiety are highly prevalent among individuals with elevated cardiometabolic risk and are associated with adverse clinical outcomes. Although dietary interventions are increasingly recognized as potential adjunctive strategies for improving mental health, their comparative effectiveness remains unclear. This study conducted a network meta-analysis to compare and rank different dietary interventions in this population. We performed a Bayesian network meta-analysis of randomized controlled trials to compare the effects of different dietary interventions on depressive and anxiety symptoms in adults with elevated cardiometabolic risk. Randomized trials evaluating dietary interventions were systematically identified, and both direct and indirect evidence were synthesized. The primary outcomes were changes in depressive and anxiety symptoms. Treatment effects were estimated as standardized mean differences (SMDs) with 95% credible intervals (CrIs). The surface under the cumulative ranking curve was used to rank interventions. Meta-regression analyses were conducted to explore the influence of baseline body mass index (BMI), age, and sex distribution. Fourteen trials involving 3,002 participants were included. Hypocaloric diets showed a greater improvement in depressive symptoms than Mediterranean-style diets (SMD, -0.27; 95% CrI, -0.55 to -0.01; Low certainty of evidence) and low‑carbohydrate diet (SMD, -0.47; 95% CrI, -0.89 to -0.07; Low certainty of evidence). Hypocaloric (SMD, -0.52; 95% CrI, -0.99 to -0.07; Low certainty of evidence), low-fat (SMD, -0.49; 95% CrI, -0.83 to -0.14; Low certainty of evidence), and Mediterranean-style (SMD, -0.48; 95% CrI, -0.89 to -0.04; Low certainty of evidence) diets were associated with greater reductions in anxiety symptoms compared with low‑carbohydrate diets. Meta-regression analyses indicated that each 1-unit increase in BMI was associated with a 0.0363-unit greater reduction in depressive symptom scores (β = -0.0363, P = 0.020). These findings were consistent in participants without preexisting depression or anxiety. In adults with elevated cardiometabolic risk, hypocaloric diets showed relatively favorable effects on depressive symptoms, while hypocaloric and low-fat diets showed favorable effects on anxiety symptoms in some comparisons. However, the certainty of evidence was moderate to low, and most comparisons were supported by limited direct evidence. Further large-scale randomized controlled trials are needed to validate these findings.