Effects of long-term ingestion of difructose anhydride III (DFA III) on intestinal bacteria and bile acid metabolism in humans.
Changes in the intestinal microbiota of 10 human subjects with long-term ingestion of 3 g/d difructose anhydride III (DFA III; 4 persons, 2 months; 3 persons, 6 months; and 3 persons, 12 months) were examined by denaturing gradient gel electrophoresis (DGGE). According to the answers to questionnaires, the subjects were divided into two groups (constipated and normal). The DGGE profile was different for every individual and each subject had unique profiles of intestinal microbiota. In the DGGE profiles of constipated subjects, the intensities of bands related to Bacteroides spp. increased. Moreover, the DFA III-assimilating bacteria, Ruminococcus sp. were isolated from subjects who ingested DFA III for 12 months. These strains showed 95% similarity of their 16S rDNA sequences with that of Ruminococcus obeum ATCC 29174(T) (X85101) and produced large amounts of acetic acid. DFA III ingestion for 2 months tended to increase total organic acids in feces, and tended to decrease fecal pH and the secondary bile acid (SBA) ratio in total bile acids. The SBA ratio in total bile acids corresponded to fecal pH. The production of SBA was decreased by low pH in vitro. These results indicated that DFA III ingestion in humans tended to lower intestinal pH, inhibited bile acid 7alpha-dehydroxylation activities and also tended to decrease the SBA ratios in total bile acids. Moreover, as another cause for the decrease in the SBA ratio in total bile acids, it was suggested that the number of bile acid 7alpha-dehydroxylating bacteria were decreased by DFA III ingestion.
Northern Advancement Center for Science and Technology, Nishi 12, Kita 21, Sapporo, Hokkaido 001-0021, Japan.
Kimiko
K
Minamida
Chikako
C
Asakawa
I Nengah
IN
Sujaya
Maki
M
Kaneko
Ayumi
A
Abe
Teruo
T
Sone
Hiroshi
H
Hara
Kozo
K
Asano
Fusao
F
Tomita
D000328:Adult; D001647:Bile Acids and Salts / Q000737:chemistry / Q000378:metabolism*; D002793:Cholic Acids / Q000378:metabolism; D004187:Disaccharides / Q000378:metabolism / Q000494:pharmacology*; D005243:Feces; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007422:Intestines / Q000382:microbiology*; D008875:Middle Aged; D045857:Ruminococcus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D001647:Bile Acids and Salts; D002793:Cholic Acids; D004187:Disaccharides; C087758:difructose anhydride III