Friday Aug. 1, 2014 (foodconsumer.org) -- A study led by scientists at Virginia Polytechnic Institute and State University in Blacksburg, Virginia, USA suggests that dietary rice bran or supplements can protect against rotavirus diarrhea.

The authors of the study report that rice bran contains phytochemicals that are known to promote gut mucosal immune response against enteric pathogens.

The current study was to test the effects of rice bran on rotavirus induced diarrhea and immunogenicity of an attenuated human rotavirus (HRV) vaccine in gnotobiotic pigs. 

For the study, four groups of animals received one of the four treatments, rice bran plus vaccine, vaccine only, rice bran only, and placebo. Rice bran was used in a dose of 10% of pigs' total daily calories from milk starting from five days of age until euthanasia.

At the 28th day after the inoculation,  a subset of animals from each group were challenged with virulent human rotavirus and were monitored daily for diarrhea and virus shedding during the first seven days post-challenge.

Supplementation with rice bran was found to significantly protect against diarrhea induced by the virulent human rotavirus and enhance the protection of the vaccine against the diarrhea.

Biochemically, rice bran supplementation was found to significantly increase IFN-γ producing CD4+ and CD8+ T-cell responses.  It also reduced the numbers of IgM, IgG and IgA cells before challenge.

The study concludes rice bran protect against rotavirus diarrhea and enhance the antiviral effect of the vaccine.

In the United States, rotavirus, the leading cause of severe diarrhea among infants and young children, causes illnesses that lead to more than 400,000 doctor visits, more than 200,000 emergency room visits, and 55,00 to 70,000 hospitalizations, and 20 to 60 deaths each year, according to the Centers for Disease Control and Prevention (CDC).

The virus infected almost all children by their fifth birthdays before the vaccine was introduced in 2006.  It takes 2 days for the virus infection to cause symptoms including severe watery diarrhea, often with vomiting, fever, and abdominal pain, according to the CDC. (David Liu)

Yang X, Wen K, Tin C, Li G, Wang H, Kocher J, Pelzer K, Ryan E, Yuan L.  Dietary rice bran protects against rotavirus diarrhea and promotes Th1 type immune responses to human rotavirus vaccine in gnotobiotic pigs.  Clin Vaccine Immunol. 2014 Jul 30.