CLOCK and ulcerative colitis: A randomized controlled trial by Firoozi et al. [42] showed how butyrate supplementation in patients diagnosed with active ulcerative colitis led to a reduction in inflammation (with a significant reduction in fecal calprotectin), as well as an upregulation of circadian clock genes and an improvement in sleep quality and quality of life, confirming the importance of SCFA in gut–brain communication.