BACKGROUND Relatively high serum carotenoid levels are associated with reduced risks of chronic diseases, but inter-individual variability in serum carotenoid concentrations is modestly explained by diet. The bacterial community in the colon could contribute to the bioaccessibility of carotenoids by completing digestion of plant cells walls and by modulating intestinal permeability. OBJECTIVE To evaluate whether colonic bacterial composition is associated with serum and colon carotenoid concentrations. DESIGN The study was a randomized dietary intervention trial in healthy individuals who were at increased risk of colon cancer. Colon mucosal biopsy samples were obtained before and after 6 months of intervention without prior preparation of the bowels. PARTICIPANTS/SETTING Participants were recruited from Ann Arbor, MI, and nearby areas from July 2007 to November 2010. Biopsy data were available from 88 participants at baseline and 82 participants after 6 months. METHODS Study participants were randomized to counseling for either a Mediterranean diet or a Healthy Eating diet for 6 months. RESULTS At baseline, bacterial communities in biopsy samples from study participants in the highest vs the lowest tertile of total serum carotenoid levels differed by several parameters. Linear discriminant analysis effect size identified 11 operational taxonomic units that were significantly associated with higher serum carotenoid levels. In linear regression analyses, three of these accounted for an additional 12% of the variance in serum total carotenoid concentrations after including body mass index, smoking, and dietary intakes in the model. These factors together explained 36% of the inter-individual variance in serum total carotenoid concentrations. The bacterial community in the colonic mucosa, however, was resistant to change after dietary intervention with either a Mediterranean diet or Healthy Eating diet, each of which doubled fruit and vegetable intakes. CONCLUSIONS The colonic mucosal bacterial community was associated with serum carotenoid concentrations at baseline but was not appreciably changed by dietary intervention.

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结肠粘膜细菌与血清类胡萝卜素浓度的个体差异有关

背景 相对较高的血清类胡萝卜素水平与慢性病风险降低有关，但血清类胡萝卜素浓度的个体间差异可以通过饮食适度地解释。结肠中的细菌群落可以通过完成植物细胞壁的消化和调节肠道通透性来促进类胡萝卜素的生物可及性。目的 评估结肠细菌组成是否与血清和结肠类胡萝卜素浓度有关。设计 该研究是一项针对结肠癌风险增加的健康个体的随机饮食干预试验。结肠黏膜活检样本是在干预 6 个月之前和之后获得的，无需事先准备肠道。参与者/设置参与者是从密歇根州安娜堡招募的，2007 年 7 月至 2010 年 11 月期间和附近地区。88 名参与者在基线时和 82 名参与者在 6 个月后可获得活检数据。方法 研究参与者被随机分配接受地中海饮食或健康饮食咨询 6 个月。结果 在基线时，来自研究参与者的活检样本中的细菌群落在总血清类胡萝卜素水平的最高和最低三分位数之间存在几个不同的参数。线性判别分析效应大小确定了 11 个操作分类单位，它们与较高的血清类胡萝卜素水平显着相关。在线性回归分析中，在模型中包括体重指数、吸烟和饮食摄入后，其中三个占血清总类胡萝卜素浓度变化的额外 12%。这些因素共同解释了血清总类胡萝卜素浓度的个体间差异的 36%。然而，在通过地中海饮食或健康饮食进行饮食干预后，结肠粘膜中的细菌群落抵抗改变，每一种饮食都会使水果和蔬菜的摄入量增加一倍。结论 结肠黏膜细菌群落与基线时的血清类胡萝卜素浓度相关，但饮食干预没有明显改变。