Department of Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.
J Nutr. 2013 May;143(5):648-55. doi: 10.3945/jn.112.172668. Epub 2013 Mar 20.
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.
富含不可消化碳水化合物的全谷物（WG）被认为可以调节肠道微生物群落的组成。我们在一项随机、平行、双臂、12 周的干预研究中调查了富含膳食纤维的黑麦面包与精制小麦面包相比，是否会影响芬兰代谢综合征 60±6 岁个体的肠道微生物群落组成。51 名参与者（25 名男性，26 名女性）在干预前后的粪便样本通过基于系统发育的微阵列和针对 16S rRNA 基因的定量聚合酶链反应进行了微生物组分析。通过食物记录计算的全谷物摄入量，食用黑麦面包组（75g）显著高于食用精制小麦面包组（4g；P＜0.001），并得到禁食血浆烷基莱菔子素浓度（全谷物摄入量的生物标志物）的证实。干预后两组肠道微生物群落组成无显著差异。然而，我们检测到食用精制小麦面包组的拟杆菌门（Bacteroidetes）减少了 37%（P＜0.05），同时烷基莱菔子素浓度降低了 53%（P＜0.001）。在该组中，与 Bacteroides vulgatus、B. plebeius 和 Prevotella tannerae 相关的细菌丰度降低，而与 Collinsella 和 Clostridium 簇 IV 和 XI 成员相关的细菌丰度增加。在多元回归分析中，拟杆菌属（Bacteroides spp.）的丰度与饮食变量中的不同脂肪化合物最佳相关，而主要的糖转化丁酸盐生产者主要与全谷物和精制谷物面包以及纤维的摄入量相关。我们的结果表明，谷物质量对代谢综合征患者肠道微生物群落组成的影响较小，并表明饮食对微生物群的影响涉及其他饮食成分，如脂肪。
