Zinc carnosine, a health food supplement that stabilises small bowel integrity and stimulates gut repair processes

Background: Zinc carnosine (ZnC) is a health food product claimed to possess health-promoting and gastrointestinal supportive activity. Scientific evidence underlying these claims is, however, limited. Aim: To examine the effect of ZnC on various models of gut injury and repair, and in a clinical trial. Methods: In vitro studies used pro-migratory (wounded monolayer) and proliferation ([ 3H]-thymidine incorporation) assays of human colonic (HT29), rat intestinal epithelial (RIE) and canine kidney (MDCK) epithelial cells. In vivo studies used a rat model of gastric damage (indomethacin/ restraint) and a mouse model of small-intestinal (indomethacin) damage. Healthy volunteers (n = 10) undertook a randomised crossover trial comparing changes in gut permeability (lactulose:rhamnose ratios) before and after 5 days of indomethacin treatment (50 mg three times a day) with ZnC (37.5 mg twice daily) or placebo coadministration. Results: ZnC stimulated migration and proliferation of cells in a dose-dependent manner (maximum effects in both assays at 100 μmol/I using HT29 cells), causing an approximate threefold increase in migration and proliferation (both p<0.01). Oral ZnC decreased gastric (75% reduction at 5 mg/ml) and small-intestinal injury (50% reduction in villus shortening at 40 mg/ml; both p<0.01). In volunteers, indomethacin caused a threefold increase in gut permeability in the control arm; lactulose:rhamnose ratios were (mean (standard error of mean)) 0.35 (0.035) before indomethacin treatment and 0.88 (0.11) after 5 days of indomethacin treatment (p<0.01), whereas no significant increase in permeability was seen when ZnC was coadministered. Conclusion: ZnC, at concentrations likely to be found in the gut lumen, stabilises gut mucosa. Further studies are warranted.