Branch of Medical Statistics, Biometry, and Epidemiology "G. A. Maccacaro", Department of Clinical Sciences and Community Health, Università Degli Studi Di Milano, Via Celoria 22, 20133, Milan, Italy.
Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Milan, Italy.
Eur J Nutr. 2023 Aug;62(5):2279-2292. doi: 10.1007/s00394-023-03110-2. Epub 2023 Apr 24.
Garlic consumption has been inversely associated to intestinal adenoma (IA) and colorectal cancer (CRC) risk, although evidence is not consistent. Gut microbiota has been implied in CRC pathogenesis and is also influenced by garlic consumption. We analyzed whether dietary garlic influence CRC risk and bacterial DNA in blood.
We conducted a case-control study in Italy involving 100 incident CRC cases, 100 IA and 100 healthy controls matched by center, sex and age. We used a validated food frequency questionnaire to assess dietary habits and garlic consumption. Blood bacterial DNA profile was estimated using qPCR and16S rRNA gene profiling. We derived odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) of IA and CRC according to garlic consumption from multiple conditional logistic regression. We used Mann-Whitney and chi-square tests to evaluate taxa differences in abundance and prevalence.
The OR of CRC for medium/high versus low/null garlic consumption was 0.27 (95% CI = 0.11-0.66). Differences in garlic consumption were found for selected blood bacterial taxa. Medium/high garlic consumption was associated to an increase of Corynebacteriales order, Nocardiaceae family and Rhodococcus genus, and to a decrease of Family XI and Finegoldia genus.
The study adds data on the protective effect of dietary garlic on CRC risk. Moreover, it supports evidence of a translocation of bacterial material to bloodstream and corroborates the hypothesis of a diet-microbiota axis as a mechanism behind the role of garlic in CRC prevention.
尽管证据并不一致，但大蒜的摄入与肠道腺瘤（IA）和结直肠癌（CRC）的风险呈负相关。肠道微生物群与 CRC 的发病机制有关，也受大蒜摄入的影响。我们分析了饮食大蒜是否会影响 CRC 风险和血液中的细菌 DNA。
我们在意大利进行了一项病例对照研究，纳入了 100 例新发 CRC 病例、100 例 IA 患者和 100 例健康对照，按中心、性别和年龄进行匹配。我们使用经过验证的食物频率问卷来评估饮食习惯和大蒜的摄入量。使用 qPCR 和 16S rRNA 基因谱来估计血液细菌 DNA 图谱。我们从多个条件逻辑回归中得出了根据大蒜摄入量得出的 IA 和 CRC 的比值比（OR）及其相应的 95%置信区间（CI）。我们使用曼-惠特尼和卡方检验来评估丰度和流行率的分类群差异。
中/高与低/无大蒜摄入相比，CRC 的 OR 为 0.27（95%CI=0.11-0.66）。血液细菌分类群的大蒜摄入量存在差异。中/高大蒜摄入量与梭状芽孢杆菌目、诺卡氏菌科和红球菌属的增加有关，与 X 家族和小金色单胞菌属的减少有关。
该研究增加了关于饮食大蒜对 CRC 风险的保护作用的数据。此外，它支持了细菌物质向血液转移的证据，并证实了饮食-微生物群轴作为大蒜预防 CRC 作用背后机制的假设。
