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

In Vivo. 2017 Jul-Aug;31(4):573-577. doi: 10.21873/invivo.11096.


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.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / administration & dosage*
  • Body Weight
  • Constipation / diet therapy*
  • Constipation / physiopathology
  • Feces
  • Gastrointestinal Diseases / diet therapy*
  • Gastrointestinal Diseases / physiopathology
  • Humans
  • Mice
  • Oryza / chemistry
  • Toll-Like Receptor 4
  • Vancomycin / administration & dosage


  • Anti-Bacterial Agents
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4
  • Vancomycin