核桃摄入与肠道微生物代谢：一项随机、交叉、对照喂养研究的探索性分析结果。

Walnut consumption and gut microbial metabolism: Results of an exploratory analysis from a randomized, crossover, controlled-feeding study.

机构信息

Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA; Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA.

Department of Biology, Juniata College, Huntingdon, PA, USA; Wright Labs, LLC, Huntingdon, PA, USA.

出版信息

Clin Nutr. 2023 Nov;42(11):2258-2269. doi: 10.1016/j.clnu.2023.09.023. Epub 2023 Sep 28.

DOI:10.1016/j.clnu.2023.09.023

PMID:37826992

Abstract

BACKGROUND & AIMS: The effect of walnut-related modulation of gut microbiota composition on microbiota functionality is unknown. The aim was to characterize the effect of a walnut-enriched diet (WD), compared to a fatty acid-matched diet devoid of walnuts (WFMD) and a diet where oleic acid replaces alpha-linolenic acid (ORAD), on bacterial gene expression.

METHODS

A 3-period, randomized, crossover, controlled-feeding study was conducted. Participants were provided a 2-week run-in standard western diet (SWD; 50% kcal carbohydrate, 16% protein, 34% fat, 12% SFA). Following the SWD in random sequence order, participants were provided the WD, WFMD, and ORAD (48% carbohydrate; 17% protein; fat 35%; 7% SFA). The WD contained 18% of energy from walnuts (57 g/d/2100 kcal). The WFMD and ORAD were devoid of walnuts; liquid non-tropical plant oils were included in these diets. Metatranscriptomic analyses were performed as an exploratory outcome.

RESULTS

The analytical sample included 35 participants (40% female) with a mean ± SD age of 43 ± 10 y and BMI of 30.3 ± 4.9 kg/m. The ⍺-diversity of taxa actively expressing genes, assessed by observed species (p = 0.27) and Pielou's Evenness (p = 0.09), did not differ among the diets. The ⍺-diversity of actively expressed genes was greater following the WD compared to the WFMD and ORAD as assessed by the observed genes and Pielou's Evenness metrics (p < 0.05). β-Diversity of the actively expressed genes differed following the WD compared to the WFMD (p = 0.001) and ORAD (p = 0.001); β-diversity did not differ between the WFMD and ORAD. Active composition analyses showed increased Gordonibacter (p < 0.001) activity following the WD vs. the ORAD. Greater expression of many genes was observed following the WD compared to the WFMD and ORAD. Following the WD, greater expression of metabolism-related genes encoding glycine amidinotransferase (GATM; K00613) and arginine deiminase (K01478) was observed compared to the WFMD. Greater expression of glycine amidinotransferase (GATM; K00613) by Gordonibacter was also observed following the WD vs. the WFMD and ORAD.

CONCLUSION

Our results suggest walnut intake may increase endogenous production of homoarginine through gut microbiota-mediated upregulation of GATM, which is a novel mechanism by which walnuts may lower cardiovascular disease risk. However, given the exploratory nature replication is needed.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov (NCT02210767).

摘要

背景与目的

核桃相关的肠道微生物群落组成的调节对微生物群落功能的影响尚不清楚。本研究旨在描述富含核桃的饮食（WD）与不含核桃的脂肪酸匹配饮食（WFMD）和用油酸替代α-亚麻酸的饮食（ORAD）相比，对细菌基因表达的影响。

方法

进行了一项 3 期、随机、交叉、对照喂养研究。参与者提供了为期 2 周的标准西方饮食（SWD；碳水化合物 50%，蛋白质 16%，脂肪 34%，饱和脂肪酸 12%）的适应期。按照随机顺序依次给予 SWD、WD、WFMD 和 ORAD（碳水化合物 48%；蛋白质 17%；脂肪 35%；饱和脂肪酸 7%）。WD 中含有 18%的核桃能量（57g/d/2100kcal）。WFMD 和 ORAD 不含核桃；这些饮食中包含液体非热带植物油。作为探索性结果进行了宏转录组分析。

结果

分析样本包括 35 名参与者（40%为女性），平均年龄 43±10 岁，BMI 为 30.3±4.9kg/m。通过观察物种（p=0.27）和皮尔逊均匀度（p=0.09）评估的活跃表达基因的 α-多样性，在不同饮食之间没有差异。与 WFMD 和 ORAD 相比，WD 后活跃表达基因的 α-多样性更高，这是通过观察到的基因和皮尔逊均匀度指标评估的（p<0.05）。WD 后活跃表达基因的 β-多样性与 WFMD （p=0.001）和 ORAD （p=0.001）不同；WFMD 和 ORAD 之间的 β-多样性没有差异。活性组成分析显示，WD 后戈登菌（Gordonibacter）的活性增加（p<0.001）。与 WFMD 和 ORAD 相比，WD 后观察到许多基因的表达增加。与 WFMD 和 ORAD 相比，WD 后与代谢相关的基因编码甘氨酸酰胺转移酶（GATM；K00613）和精氨酸脱氨酶（K01478）的表达增加。与 WFMD 和 ORAD 相比，WD 后戈登菌（Gordonibacter）的甘氨酸酰胺转移酶（GATM；K00613）表达也增加。