Gargari Giorgio, Taverniti Valentina, Del Bo' Cristian, Bernardi Stefano, Hidalgo-Liberona Nicole, Meroño Tomás, Andres-Lacueva Cristina, Kroon Paul A, Cherubini Antonio, Riso Patrizia, Guglielmetti Simone
Division of Food Microbiology and Bioprocesses, Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Via Celoria 2, 20133, Milan, Italy.
Division of Human Nutrition, Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Milan, Italy.
Eur J Nutr. 2022 Apr;61(3):1209-1220. doi: 10.1007/s00394-021-02680-3. Epub 2021 Nov 2.
Aging can be characterized by increased systemic low-grade inflammation, altered gut microbiota composition, and increased intestinal permeability (IP). The intake of polyphenol-rich foods is proposed as a promising strategy to positively affect the gut microbiota-immune system-intestinal barrier (IB) axis. In this context, we tested the hypothesis that a PR-dietary intervention would affect the presence of bacterial factors in the bloodstream of older adults.
We collected blood samples within a randomized, controlled, crossover intervention trial in which older volunteers (n = 51) received a polyphenol-enriched and a control diet. We quantified the presence of bacterial DNA in blood by qPCR targeting the 16S rRNA gene (16S; bacterial DNAemia). Blood DNA was taxonomically profiled via 16S sequencing.
Higher blood 16S levels were associated with higher BMI and markers of IP, inflammation, and dyslipidemia. PR-intervention did not significantly change bacterial DNAemia in the older population (P = 0.103). Nonetheless, the beneficial changes caused by the polyphenol-enriched diet were greatest in participants with higher bacterial DNAemia, specifically in markers related to IP, inflammation and dyslipidemia, and in fecal bacterial taxa. Finally, we found that the bacterial DNA detected in blood mostly belonged to γ-Proteobacteria, whose abundance significantly decreased after the polyphenol-rich diet in subjects with higher bacterial DNAemia at baseline.
This study shows that older subjects with higher bacterial DNAemia experienced a beneficial effect from a polyphenol-rich diet. Bacterial DNAemia may be a further relevant marker for the identification of target populations that could benefit more from a protective dietary treatment.
This trial was retrospectively registered at www.isrctn.org (ISRCTN10214981) on April 28, 2017.
衰老的特征包括全身性低度炎症增加、肠道微生物群组成改变以及肠道通透性（IP）增加。摄入富含多酚的食物被认为是一种有望积极影响肠道微生物群 - 免疫系统 - 肠道屏障（IB）轴的策略。在此背景下，我们检验了以下假设：富含多酚的饮食干预会影响老年人血液中细菌因子的存在情况。
我们在一项随机、对照、交叉干预试验中采集了血液样本，其中老年志愿者（n = 51）接受了富含多酚的饮食和对照饮食。我们通过靶向16S rRNA基因（16S；细菌血症）的qPCR定量血液中细菌DNA的存在情况。通过16S测序对血液DNA进行分类分析。
较高的血液16S水平与较高的体重指数以及IP、炎症和血脂异常标志物相关。富含多酚的干预并未显著改变老年人群中的细菌血症（P = 0.103）。尽管如此，富含多酚的饮食所带来的有益变化在细菌血症较高的参与者中最为显著，特别是在与IP、炎症和血脂异常相关的标志物以及粪便细菌分类群方面。最后，我们发现血液中检测到的细菌DNA大多属于γ-变形菌门，在基线时细菌血症较高的受试者中，富含多酚的饮食后其丰度显著降低。
本研究表明，细菌血症较高的老年受试者从富含多酚的饮食中获益。细菌血症可能是用于识别可能从保护性饮食治疗中获益更多的目标人群的另一个相关标志物。
该试验于2017年4月28日在www.isrctn.org（ISRCTN10214981）进行了回顾性注册。
