Improvement Effect of Dewaxed Brown Rice on Constipation in Antibiotic-treated Mice

Abstract

Background/aim: A decrease in gastrointestinal motility causing weakened lipopolysaccharide (LPS) - toll-like receptor (TLR)4 signaling along with a decline in the number of enteric bacteria is known to be a cause of constipation due to the administration of antibiotics. A new type of brown rice with its wax layer removed, resulting in quick-cooking and tasty product, contains 100-times more LPS than polished white rice. In this study, the improvement effect on constipation due to intake of dewaxed brown rice was examined.

Materials and methods: Dewaxed brown rice was prepared at Toyo Rice from brown rice. Mice were given powdered feed to which powdered rice containing 0-50% of dewaxed brown rice was added. Antibiotics were administered for 10 or 27 days in drinking water containing vancomycin, metronidazole and neomycin. LPS, used as a control, was freely provided in drinking water. The defecation frequency, stool weight per hour and body weight were determined on the last day.

Results: Although the 10-day administration of antibiotics reduced the stool weight per hour to half, the dewaxed brown rice and LPS groups showed a trend towards improvement at a level comparable to the group receiving no antibiotics. The body weight significantly decreased after the 27-day administration of antibiotics but was improved in the 50% dewaxed brown rice group at a level comparable to the group receiving no antibiotics. Though the defecation frequency and wet and dry stool weights per hour were reduced by as much as 50% in the group receiving antibiotics, a significant improvement in constipation was observed in the 50% dewaxed brown rice group.

Conclusion: As the improvement effect of dewaxed brown rice on body weight loss and constipation caused by the long-term administration of antibiotics has been confirmed in animal experimentation, the introduction of dewaxed brown rice as a staple food to patients under long-term antibiotic treatment may improve constipation.

Keywords: Brown rice; antibiotics; constipation; lipopolysaccharide.