Studies on variations in short-chain fatty acids (SCFAs) in patients with ulcerative colitis (UC) have reached inconsistent conclusions, according to an article in BMC Gastroenterology. In a meta-analysis, investigators reviewed studies on the role of SCFAs in patients with UC and reported that compared with healthy subjects, those with UC had considerably reduced concentrations of total SCFAs, acetate, propionate, and valerate.

Additionally, the investigators reported that “inconsistent changes of certain special SCFAs were observed in UC patients with different disease status.”

A total of 11 studies were included in the meta-analysis. Investigators calculated that patients with UC had significantly lower concentrations of total SCFAs (standardized mean difference (SMD) = –0.88; 95% confidence interval [CI], –1.44 to –0.33; p <.001), acetate (SMD = –0.54; 95% CI, –0.91 to –0.17; p = .004), propionate, (SMD = –0.37; 95% CI, –0.66 to –0.07; p = .016), and valerate (SMD = –0.91; 95% CI, –1.45 to –0.38; p <.001).

After analyzing subgroups based on disease stage, authors found that patients with active UC had reduced concentrations of acetate (SMD = –1.83; 95% CI, –3.32 to –0.35; p = .015), propionate (SMD = –2.51; 95% CI, –4.41 to –0.61; p = .009), and valerate (SMD = –0.91, 95% CI, –1.45 to –0.38; p <.001). Conversely, patients with UC in remission had concentrations similar to healthy subjects. Furthermore, patients with active UC had lower butyrate levels (SMD = –2.09; 95% CI, –3.56 to –0.62; p = .005), while patients in remission had higher butyrate levels (SMD = 0.71; 95% CI, 0.33–1.10; p <.001) when compared with healthy subjects.

The researchers summarized that total SCFAs, acetate, propionate, and valerate were significantly reduced in patients with UC when compared with controls, with the potential for further alterations in SCFAs based on disease stage—though they called for further research to explore these observations.