Improvement of defecation in healthy individuals with infrequent bowel movements through the ingestion of dried Mozuku powder: a randomized, double-blind, parallel-group study

Background: Okinawa mozuku (Cladosiphon okamuranu) is a type of edible seaweed of the family Chordariaceae that typically contains the polysaccharide fucoidan as a functional ingredient. In Okinawa, raw mozuku is eaten as vinegared mozuku together with vinegar or as tempura (deep-fried in batter). Polysaccharides such as fucoidan are generally known to regulate intestinal function, which is why we have used Okinawa mozuku to investigate this intestinal regulatory effect.Methods: The study was designed as a randomized, double-blind, parallel group study. Dried Okinawa mozuku powder at a dose of 2.4 g/day (1.0 g/day of fucoidan) and a placebo not containing any dried Okinawa mozuku powder were each made into capsules and given to healthy men and women with infrequent weekly bowel movements (2–4 movements a week) to ingest for eight weeks. We then investigated changes in the defecation situation, blood tests, and adverse events. Results: In the group that ingested the capsules containing dried Okinawa mozuku powder, the number of days with a bowel movement significantly increased compared with the placebo group after four weeks of ingestion (p < 0.05). Furthermore, after eight weeks of ingestion, the same increasing trend was seen compared with the placebo group (p = 0.0964). The volume of stool also increased significantly in the dried Okinawa mozuku powder group after eight weeks compared with the placebo group. In terms of blood tests and adverse events, no adverse events occurred that were the result of the test food.Conclusions: Ingestion of Okinawa mozuku was found to have a regulatory effect on intestinal function by promoting defecation in healthy individuals with a tendency for constipation. This demonstrated that Okinawa mozuku is a functional food capable of making defecation smoother and increasing the volume of stool.Key Words: Okinawa mozuku, Cladosiphon okamuranus, fucoidan, dry powder, bowel movement, constipation