The effects of various nutritional supplements in patients with chronic obstructive pulmonary disease: a network meta-analysis

Abstract

Objective: To evaluate the effectiveness of various nutritional supplements as interventions for patients with Chronic Obstructive Pulmonary Disease (COPD) using network meta-analysis.

Methods: We searched PubMed, Embase, Cochrane Library, and Web of Science databases for randomized controlled trials on nutritional supplements for COPD patients, with the search updated to March 24, 2025. The risk of bias for each included study was assessed using appropriate tools, and the certainty of evidence was evaluated according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Data synthesis was performed using R software, employing network meta-analysis methods to compare the relative efficacy of different nutritional interventions.

Results: Thirty-seven studies involving 1975 COPD patients and 21 different nutritional supplements were analyzed. Butyrate [MD = 2.7, 95% CrI (1.0, 4.4)], Nanocurcumin [MD = 13, 95% CrI (5.4, 21)], and probiotics [MD = 7.1, 95% CrI (5.2, 9.1)] significantly improved Forced Expiratory Volume in One Second (FEV1). Nanocurcumin also slowed the decline in the ratio of Forced Expiratory Volume in One Second to Forced Vital Capacity (FEV1/FVC) [MD = 12, 95% CrI (5.5, 18)]. For exercise endurance, coenzyme Q10 combined with creatine [MD = 63, 95% CrI (36, 90)], Melatonin (MLT) [MD = 46, 95% CrI (1.3, 92)], Nitrate [MD = 30, 95% CrI (19, 41)], and whey proteins [MD = 11, 95% CrI (9.2, 13)] significantly improved 6-minute walk distance (6MWD). Regarding dyspnea reduction, MLT [MD = -0.90, 95% CrI (-1.6, -0.21)] and Yam-Epimedium [MD = -1.3, 95% CrI (-1.9, -0.67)] significantly lowered modified Medical Research Council (mMRC) scores. In terms of quality of life, MLT [MD = -8, 95% CrI (-12, -4.2)], Vitamin D (VD) [MD = -2.5, 95% CrI (-3.1, -1.9)], and whey proteins [MD = -0.70, 95% CrI (-0.99, -0.41)] reduced COPD Assessment Test (CAT) scores. Additionally, AKL1 [MD = -9.2, 95% CrI (-18, -0.41)], creatine [MD = -9.6, 95% CrI (-17, -2.8)], and Yam-Epimedium [MD = -24, 95% CrI (-34, -13)] lowered St. George's Respiratory Questionnaire (SGRQ) scores. The Surface Under the Cumulative Ranking Curve (SUCRA) analysis showed Nanocurcumin ranked highest for improving FEV1/FVC, coenzyme Q10 combined with creatine for 6MWD, Yam-Epimedium for reducing dyspnea and SGRQ, and MLT for lowering CAT scores.

Conclusion: This analysis indicates that various nutritional supplements, including Nanocurcumin, butyrate, probiotics, coenzyme Q10 combined with creatine, MLT, nitrate, whey proteins, VD, AKL1, creatine, and Yam-Epimedium, can potentially benefit COPD patients, demonstrating differing levels of effectiveness. Specifically, Nanocurcumin may be the best choice for improving lung function; coenzyme Q10 combined with creatine may be the most effective for enhancing exercise endurance; Additionally, Yam-Epimedium is the most likely supplement to reduce the symptoms of dyspnea in COPD patients. Yam-Epimedium and MLT may be the most effective for improving quality of life and overall health status.

Keywords: Chronic obstructive pulmonary disease; Dietary supplement; Network meta-analysis.

Fig. 1

PRISMA flow diagram

Fig. 2

Risk of bias graph

Fig. 3

Risk of bias summary

Fig. 4

Network plots of the included nutritional supplements and their connections based on the efficacy outcomes. The size of the nodes corresponds to the number of studies involving that particular intervention. The thickness of the edges represents the number of studies comparing the two interventions. Panels (a–f): Each panel represents a specific outcome or analysis based on the included studies: a. Forced Expiratory Volume in One Second (FEV1) (% of predicted). b. The ratio of Forced Expiratory Volume in One Second to Forced Vital Capacity (FEV1/FVC). c. 6-minute walk distance (6MWD); d. modified Medical Research Council (mMRC) Dyspnea Scale. e. COPD Assessment Test (CAT). f. St. George’s Respiratory Questionnaire (SGRQ). EAA = Essential amino acid, EPA = Eicosapentaenoic acid, MLT = Melatonin, VD = Vitamin D, VC = Vitamin C, VE = Vitamin E, OPC = Oligomeric proanthocyanidin, AKL1 = a patented botanical formulation containing extracts of Picrorhiza kurroa, Ginkgo biloba, and Zingiber officinale

Fig. 5

The cumulative sorting curve. Panels (a-f): Each panel represents the probability ranking of interventions for specific outcomes: a. Forced Expiratory Volume in One Second (FEV1) (% of predicted); b. The ratio of Forced Expiratory Volume in One Second to Forced Vital Capacity (FEV1/FVC); c. 6-minute walk distance (6MWD); d. modified Medical Research Council (mMRC) Dyspnea Scale; e. COPD Assessment Test (CAT); f. St. George’s Respiratory Questionnaire (SGRQ). EAA = Essential amino acid, EPA = Eicosapentaenoic acid, MLT = Melatonin, VD = Vitamin D, VC = Vitamin C, VE = Vitamin E, OPC = Oligomeric proanthocyanidin, AKL1 = a patented botanical formulation containing extracts of Picrorhiza kurroa, Ginkgo biloba, and Zingiber officinale

Fig. 6

Funnel plots of the outcomes: (a) Forced Expiratory Volume in One Second (FEV1) (% of predicted); (b) The ratio of Forced Expiratory Volume in One Second to Forced Vital Capacity (FEV1/FVC); (c) 6-minute walk distance (6MWD); (d) modified Medical Research Council (mMRC) Dyspnea Scale; (e) COPD Assessment Test (CAT); (f) St. George’s Respiratory Questionnaire (SGRQ). EAA = Essential amino acid, EPA = Eicosapentaenoic acid, MLT = Melatonin, VD = Vitamin D, VC = Vitamin C, VE = Vitamin E, OPC = Oligomeric proanthocyanidin, AKL1 = a patented botanical formulation containing extracts of Picrorhiza kurroa, Ginkgo biloba, and Zingiber officinale