Colon to Rectum
Gastroenterology. 2022;163(5):1294–305.e3
Effect of 5-hydroxytryptophan on fatigue in quiescent inflammatory bowel disease: A randomized controlled trial
Background and aims: Fatigue is highly prevalent among patients with inflammatory bowel disease (IBD), and only limited treatment options are available. Based on the hypothetical link between low serum tryptophan concentrations and fatigue, the authors determined the effect of 5-hydroxytryptophan (5-HTP) supplementation on fatigue in patients with inactive IBD.
Methods: A multicenter randomized controlled trial was performed at 13 Belgian hospitals, including 166 patients with IBD in remission but experiencing fatigue, defined by a fatigue visual analog scale (fVAS) score of ≥ 5. Patients were treated in a crossover manner with 100 mg oral 5-HTP or placebo twice daily for 2 consecutive periods of 8 weeks. The primary end point was the proportion of patients reaching a ≥ 20% reduction in fVAS after 8 weeks of intervention. Secondary outcomes included changes in serum tryptophan metabolites, Functional Assessment of Chronic Illness Therapy Fatigue scale, and scores for depression, anxiety, and stress. The effect of the intervention on the outcomes was evaluated by linear mixed modeling.
Results: During 5-HTP treatment, a significant increase in serum 5-HTP (estimated mean difference, 52.66 ng/ml; 95% confidence interval [CI]: 39.34–65.98 ng/ml; p < 0.001) and serotonin (3.0 ng/ml; 95% CI: 1.97–4.03 ng/ml; p < 0.001) levels was observed compared with placebo. The proportion of patients reaching ≥ 20% reduction in fVAS was similar in placebo- (37.6%) and 5-HTP (35.6%)-treated patients (p = 0.830). The fVAS reduction (-0.18; 95% CI: -0.81–0.46; p = 0.581) and Functional Assessment of Chronic Illness Therapy Fatigue scale increase (0.68; 95% CI: -2.37–3.73; p = 0.660) were both comparable between 5-HTP and placebo treatment as well as changes in depression, anxiety, and stress scores.
Conclusions: Despite a significant increase in serum 5-hydroxytryptophan (5-HTP) and serotonin levels, oral 5-HTP did not modulate inflammatory bowel disease-related fatigue better than placebo.