The capacity of nondigestible carbohydrates to stimulate fecal bifidobacteria in healthy humans: a double-blind, randomized, placebo-controlled, parallel-group, dose-response relation study.
BACKGROUND
Nondigestible carbohydrates (NDCHs) are fermented in the colon, where they can selectively promote the growth of bifidobacteria.


OBJECTIVE
Our aim was to determine the bifidogenic potential of different NDCHs used in human diets.


METHODS
Two hundred healthy volunteers participated in this double-blind study. During phase 1 (screening), 64 volunteers were randomly assigned to 8 groups of 8 subjects each; for 7 d, they ingested 10 g/d of 1 of the 7 NDCHs tested or of the placebo. During phase 2 (dose-response study), 136 volunteers were randomly assigned to 4 groups of 32 subjects who received 2.5, 5.0, 7.5, or 10 g/d, respectively (8 subjects/dose), of one of the NDCHs that were proven to be bifidogenic during phase 1 and a fifth group of 8 subjects (control subjects) who received the placebo. Stools were recovered before and after NDCH consumption.


RESULTS
In phase 1, 4 NDCHs were found to be bifidogenic: short-chain fructooligosaccharides (P=0.008), soybean oligosaccharides (P=0.006), galactooligosaccharides (P <0.0001), and type III resistant starch (P=0.02); lactulose, long-chain inulin, and isomaltooligosaccharides were not bifidogenic. In phase 2, the effects of 7-d treatment on bifidobacteria concentrations were found to differ significantly among the 4 NDCHs (P=0.009 for time x treatment interaction). However, no significant differences were found among doses, and there was no significant dose x time interaction. A low baseline bifidobacteria count was significantly associated with the bifidogenic response to treatment (P <0.001).


CONCLUSIONS
This study showed the different bifidogenic properties among the substrates and underlined the importance of taking into account the baseline bifidobacteria counts when evaluating the effect of the treatment.
Bouhnik
Yoram
Y
Department of Gastroenterology and the Therapeutic Research Unit, Hôpital Lariboisière, Paris, France. yoram.bouhnik@lrb.ap-hop-paris.fr
Raskine
Laurent
L
Simoneau
Guy
G
Vicaut
Eric
E
Neut
Christel
C
Flourié
Bernard
B
Brouns
Fred
F
Bornet
Francis R
FR
D000293:Adolescent; D000328:Adult; D001644:Bifidobacterium / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D003106:Colon / Q000378:metabolism* / Q000382:microbiology*; D015169:Colony Count, Microbial; D004043:Dietary Fiber / Q000008:administration & dosage* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005243:Feces / Q000382:microbiology; D005260:Female; D005285:Fermentation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009844:Oligosaccharides / Q000008:administration & dosage / Q000378:metabolism; D013025:Glycine max; D013213:Starch / Q000008:administration & dosage / Q000378:metabolism
D004043:Dietary Fiber; D009844:Oligosaccharides; C116580:fructooligosaccharide; D013213:Starch