Objective To investigate whether a whole grain diet alters the gut microbiome and insulin sensitivity, as well as biomarkers of metabolic health and gut functionality. Design 60 Danish adults at risk of developing metabolic syndrome were included in a randomised cross-over trial with two 8-week dietary intervention periods comprising whole grain diet and refined grain diet, separated by a washout period of ≥6 weeks. The response to the interventions on the gut microbiome composition and insulin sensitivity as well on measures of glucose and lipid metabolism, gut functionality, inflammatory markers, anthropometry and urine metabolomics were assessed. Results 50 participants completed both periods with a whole grain intake of 179±50 g/day and 13±10 g/day in the whole grain and refined grain period, respectively. Compliance was confirmed by a difference in plasma alkylresorcinols (p<0.0001). Compared with refined grain, whole grain did not significantly alter glucose homeostasis and did not induce major changes in the faecal microbiome. Also, breath hydrogen levels, plasma short-chain fatty acids, intestinal integrity and intestinal transit time were not affected. The whole grain diet did, however, compared with the refined grain diet, decrease body weight (p<0.0001), serum inflammatory markers, interleukin (IL)-6 (p=0.009) and C-reactive protein (p=0.003). The reduction in body weight was consistent with a reduction in energy intake, and IL-6 reduction was associated with the amount of whole grain consumed, in particular with intake of rye. Conclusion Compared with refined grain diet, whole grain diet did not alter insulin sensitivity and gut microbiome but reduced body weight and systemic low-grade inflammation. Trial registration number NCT01731366; Results.

中文翻译：

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富含全谷物的饮食可减轻体重和全身性低度炎症，而不会引起肠道微生物组的重大变化：一项随机交叉试验

目的 研究全麦饮食是否会改变肠道微生物组和胰岛素敏感性，以及代谢健康和肠道功能的生物标志物。设计 60 名有发生代谢综合征风险的丹麦成年人被纳入一项随机交叉试验，该试验有两个 8 周的饮食干预期，包括全谷物饮食和精制谷物饮食，间隔时间为 ≥ 6 周。评估了对肠道微生物组组成和胰岛素敏感性以及葡萄糖和脂质代谢、肠道功能、炎症标志物、人体测量学和尿液代谢组学的干预措施的反应。结果 50 名参与者在全谷物和精制谷物期间分别以 179±50 克/天和 13±10 克/天的全谷物摄入量完成了这两个阶段。血浆烷基间苯二酚的差异证实了顺应性（p<0.0001）。与精制谷物相比，全谷物不会显着改变葡萄糖稳态，也不会引起粪便微生物组的重大变化。此外，呼吸氢水平、血浆短链脂肪酸、肠道完整性和肠道转运时间均未受到影响。然而，与精制谷物饮食相比，全谷物饮食确实降低了体重 (p<0.0001)、血清炎症标志物、白细胞介素 (IL)-6 (p=0.009) 和 C-反应蛋白 (p=0.003)。体重的减少与能量摄入的减少是一致的，IL-6 的减少与全谷物的消耗量有关，尤其是黑麦的摄入量。结论与精粮饮食相比，全麦饮食不会改变胰岛素敏感性和肠道微生物组，但会降低体重和全身性低度炎症。试验注册号NCT01731366；结果。