Abstract
Whole-grain (WG) foods rich in indigestible carbohydrates are thought to
modulate the composition of the intestinal microbiota. We investigated
in a randomized, parallel, 2-arm 12-wk intervention whether consumption
of WG and fiber-rich rye breads compared with refined wheat breads
affected the microbiota composition in Finnish individuals aged 60 ± 6 y
with metabolic syndrome. Fecal samples from 51 participants (25 males,
26 females) before and after the intervention were processed for the
microbiota analysis using a phylogenetic microarray and quantitative
polymerase chain reactions targeting the 16S rRNA gene. The intake of
whole grains calculated from food records was higher in the group
consuming rye breads (75 g) than in that consuming refined wheat breads
(4 g; P < 0.001), confirmed by fasting plasma
alkylrecorsinol concentrations, a biomarker of whole grain intake. The
intestinal microbiota composition did not significantly differ between
the groups after the intervention. However, we detected a 37% decrease
of Bacteroidetes (P < 0.05) in parallel to a 53% decrease in the alkylrecorsinol concentration (P < 0.001) in the group consuming refined wheat breads. In this group, the abundance of bacteria related to Bacteroides vulgatus, B. plebeius, and Prevotella tannerae decreased, whereas that of bacteria related to Collinsella and members of the Clostridium clusters IV and XI increased. In a multivariate regression analysis, the abundance of Bacteroides
spp. was best explained by different fat compounds among dietary
variables, whereas the main sugar-converting butyrate-producers were
mostly associated with the intake of whole- and refined-grain bread and
fiber. Our results indicate that the quality of grains has a minor
effect on the intestinal microbiota composition in participants with
metabolic syndrome and suggest that the dietary influence on the
microbiota involves other dietary components such as fat.
Original language | English |
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Pages (from-to) | 648-655 |
Number of pages | 8 |
Journal | Journal of Nutrition |
Volume | 143 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2013 |
MoE publication type | A1 Journal article-refereed |