Effect of a double-coated probiotic formulation on functional constipation in the elderly: a randomized, double blind, controlled study.

A randomized, double blind, controlled study was conducted to evaluate a multi-species probiotic product, Duolac(®) Care, for the efficacy in functional constipation of elderly nursing home residents. Forty participants were randomly assigned to receive either one capsule containing six bacterial strains (2.5 × 10(8) viable cells/capsule) doubly coated with proteins and polysaccharides (DC group) or one capsule containing the same bacterial strains without the coating layers outside the cell (NC group) twice a day (5 × 10(8) viable cells/day). After consumption of 2 weeks, NC group showed a significant improvement in a symptom of Rome III criteria for constipation, 'effort to evacuate', but failed to show a significant improvement in weekly defecation frequency. By contrast, DC group showed significant improvements in symptoms of 'effort to evacuate' and 'sensation of anorectal obstruction or blockage' as well as being improved in 'defecation frequency'. The quantitative analysis of the fecal bacteria revealed that the levels of all the bacterial species consumed were significantly increased after consumption in both groups. However DC group showed larger increases in the bacterial levels than NC group, and the overall bacterial levels in DC group were about 100-fold or greater than those in NC group. Therefore the improvements in the symptoms appeared to be closely associated with large increases of the bacterial species consumed. The double-coating layers of proteins and polysaccharides ensured increase in the levels of bacteria, indicating that the layers function to protect the bacteria from the digestive action in the GI tract. Therefore, Duolac(®) Care could be a treatment option in functional constipation.