Efficacy and safety of dietary supplements for the treatment of ulcerative colitis, a network meta-analysis

Background In recent years, the application of dietary supplements in the treatment of ulcerative colitis (UC) has attracted more and more scholars’ attention, and a number of studies have shown that dietary supplements have a non-negligible role in improving the clinical symptoms and quality of life of UC patients. This article aims to compare the efficacy and safety of dietary supplement therapy of UC through a comprehensive network meta-analysis method. Methodology A comprehensive literature search was conducted in multiple databases, including PubMed, the Cochrane Library, Embase, and Web of science, from their inception up to 30 October 2025. Network and routine meta-analyses using the mvmeta package in Stata 16.0 and Stata 12.0 software, and literature quality and risk of bias assessed using RevMan 5.3 software. Result A total of 24 randomized controlled trials were conducted with 1,491 participants and 14 dietary supplements. The results showed that probiotics MD = −1.64, 95% CI (−2.91 to −0.38) and selenium MD = −2.43, 95% CI (−4.85 to −0.01) had significant advantages compared with conventional medical treatment or placebo in reducing clinical activity index. Flaxseed extract MD = −1.53, 95% CI (−2.82 to −0.24) and vitamin A MD = −1.93, 95% CI (−3.82 to −0.04) had a clear advantage over conventional medical treatment or placebo in reducing the Mayo score; at the same time, in terms of IBDQ, probiotics MD = 7.78, 95% CI (1.39 to 14.17), flaxseed extract MD = 8.58, 95% CI (2.31 to 14.85), resveratrol MD = 9.18, 95% CI (2.45 to 15.91), curcumin MD = 25.80, 95% CI (2.00 to 49.60), butyrate MD = 20.50, 95% CI (9.80, 31.20) with higher scores compared to conventional drugs or placebo, indicating an improved quality of life for patients; synbiotics MD = −0.69, 95% CI (−1.16 to −0.23), flaxseed extract MD = −0.8, 95% CI (−1.16 to −0.44), and Achillea wilhelmsii MD = −2.95, 95% CI (−3.52 to −2.38) all showed significant advantages compared with conventional medical therapy or placebo for reducing C-reactive protein levels. Conclusion Various dietary supplements have shown differentiated efficacy in adjuvant UC therapy. Probiotics and selenium are effective in improving clinical symptoms; flaxseed extract showed consistent benefits in improving Mayo score, IBDQ score, and reducing CRP, ESR, and FCAL, and had a wide range of application prospects. Butyrate and curcumin have significant effects in improving quality of life; synbiotics and Achillea wilhelmsii have outstanding advantages in reducing CRP. Due to the limitations of the number and quality of included studies, the above conclusions still need to be validated by more high-quality, large-sample RCTs.