**5. Conclusions**

The present data illustrated that fucoidan absorption is associated with *H. pylori* infection and mozuku consumption. Fucoidan absorption in *H. pylori*-positive subjects who regularly consumed mozuku differed by age, being significantly lower in subjects aged ≥40 years than in their younger counterparts. A significant positive correlation between the basal fucoidan level and ΔMax fucoidan value was found among subjects aged <40 who regularly consumed mozuku but not among their older counterparts. Further studies are needed to elucidate the precise mechanisms influencing fucoidan absorption.

**Author Contributions:** T.N. designed the experiments and wrote the manuscript, M.T. wrote the manuscript; M.I. reviewed the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** We would like to thank Kizuku Kadena for assistance with all experiments. In addition, we would like to thank Assistant Professor Kenji Nakamura (Takasaki University of Health and Welfare) for his helpful advice regarding the statistical analysis.

**Conflicts of Interest:** The authors declare no conflicts of interest.
