Clinical trial: protective effect of a commercial fish protein hydrolysate against indomethacin (NSAID)‐induced small intestinal injury

Summary Background  A partially hydrolysed and dried product of pacific whiting fish is marketed as a health food supplement supporting ‘intestinal health’. Aim  To examine whether the partially hydrolysed and dried product of pacific whiting fish influenced the small intestinal damaging side effects of the nonsteroidal anti‐inflammatory drug, indomethacin. Methods  Eight human volunteers completed a double‐blind, placebo‐controlled, crossover protocol of clinically relevant dose of indomethacin (50 mg t.d.s. p.o. for 5 days) with 7 days of fish hydrolysate or placebo starting 2 days prior to indomethacin. Changes in gut permeability were assessed using 5 h urinary lactulose:rhamnose (L/R) ratios. Results  Fish hydrolysate given alone did not affect permeability. In the main study ( n  = 8), baseline values were similar for both arms (0.28 ± 0.05 and 0.35 ± 0.07). Administration of indomethacin (+placebo) caused a fivefold rise in L/R ratios (increasing to 1.54 ± 0.35), whereas L/R ratios in the same subjects ingesting indomethacin + fish hydrolysate was only 0.59 ± 0.14 ( P  < 0.01 vs. indomethacin alone). Dyspeptic symptoms occurred in four of eight subjects taking indomethacin alone, but zero of eight when hydrolysate was co‐administered. Conclusion  Natural bioactive products (nutriceuticals), such as fish hydrolysates, may provide a novel approach to the prevention and treatment of NSAID‐induced and other gastrointestinal injurious conditions.