Enhancing Oral 5-ASA Effectiveness in Mild-to-Moderate Ulcerative Colitis through an H. erinaceus-Based Nutraceutical Add-on Multi-Compound: The “HERICIUM-UC” Two-Arm Multicentre Retrospective Study

Mild-to-moderate ulcerative colitis (UC) management is centred on 5-aminosalicylic acid (5-ASA) derivatives. Whether supplementing 5-ASA with nutraceuticals can provide real advantages in UC-relevant outcomes is unclear. This retrospective multicentre study compared clinical remission, response rates, and faecal calprotectin levels in a two-arm design, including patients treated with 5-ASA alone and those with additional H. erinaceus-based multi-compound supplementation. In the 5-ASA alone group, clinical response rates were 41% at three months (T1) and 60.2% at six months (T2), while corresponding clinical remission rates were 16.9% and 36.1%. In the nutraceutical supplementation group, clinical response rates were 49.6% (T1) and 70.4% (T2), with clinical remission rates of 30.4% (T1) and 50.9% (T2). No significant differences in clinical response rates between the groups at T1 (p = 0.231) and T2 (p = 0.143) emerged. Clinical remission rates differed significantly at both time points (p = 0.029 and p = 0.042, respectively). Faecal calprotectin levels decreased significantly in both groups during the retrospective follow-up (p < 0.05), and this was more pronounced in nutraceutical supplementation patients at both T1 (p = 0.005) and T2 (p = 0.01). No adverse events were reported. This multi-component nutraceutical supplementation offers real-world potential in controlling disease activity in patients with mild-to-moderate UC.