Département de sciences biologiques, Université de Montréal, 90 Vincent-d'Indy, Montréal, Qc, H2V2S9, Canada.
Center for Northern Studies, Département de sciences biologiques, Université de Montréal, 90 Vincent-d'Indy, Montréal, Qc, H2V2S9, Canada.
Microbiome. 2017 Nov 16;5(1):151. doi: 10.1186/s40168-017-0370-7.
The human gut microbiome represents a diverse microbial community that varies across individuals and populations, and is influenced by factors such as host genetics and lifestyle. Diet is a major force shaping the gut microbiome, and the effects of dietary choices on microbiome composition are well documented. However, it remains poorly known how natural temporal variation in diet can affect the microbiome. The traditional Inuit diet is primarily based on animal products, which are thought to vary seasonally according to prey availability. We previously investigated the Inuit gut microbiome sampled at a single time point, and found no detectable differences in overall microbiome community composition attributable to the traditional Inuit diet.
To determine whether seasonal changes in the Inuit diet might induce more pronounced changes in the microbiome, we collected stool and toilet paper samples, and dietary information from Inuit volunteers living in Resolute Bay (Nunavut, Canada), and compared them to individuals of European descent living in Montréal (Québec, Canada) consuming a typical Western diet. We sequenced the V4 region of the 16S rRNA gene to characterize microbiome diversity and composition, and compared samples collected with toilet paper or from stool. Our results show that these sampling methods provide similar, but non-identical portraits of the microbiome. Based on toilet paper samples, we found that much of the variation in microbiome community composition could be explained by individual identity (45-61% of variation explained, depending on the beta diversity metric used), with small but significant variation (3-5%) explained by sex or geography (Nunavut or Montréal). In contrast with our previous study at one time point, sampling over the course of a year revealed that diet explains 11% of variation in community composition across all participants, and 17% of variation specifically among Nunavut participants. However, we observed no clear seasonal shifts in the microbiomes of participants from either Nunavut or Montréal. Within-individual microbial diversity fluctuated more over time in Nunavut than in Montréal, consistent with a more variable and highly individualized diet in Nunavut.
Together, these results shows that the traditional Inuit diet and lifestyle has an impact on the composition, diversity and stability of the Inuit gut microbiome, even if the seasonality of the diet is less pronounced than expected, perhaps due to an increasingly westernized diet.
人类肠道微生物组代表了一个多样化的微生物群落，它在个体和人群之间存在差异，并受到宿主遗传和生活方式等因素的影响。饮食是塑造肠道微生物组的主要力量，饮食选择对微生物组组成的影响已有充分的记录。然而，人们对饮食的自然时间变化如何影响微生物组知之甚少。传统的因纽特饮食主要以动物产品为基础，这些产品据认为会根据猎物的可获得性而季节性变化。我们之前调查了在单个时间点采集的因纽特肠道微生物组，没有发现因传统因纽特饮食而导致的整体微生物群落组成的可检测差异。
为了确定因纽特饮食的季节性变化是否会引起微生物组更明显的变化，我们从居住在努勒维特地区的因纽特志愿者（加拿大）收集了粪便和卫生纸样本以及饮食信息，并将其与居住在魁北克省蒙特利尔市（加拿大）的食用典型西方饮食的欧洲血统个体进行了比较。我们对 16S rRNA 基因的 V4 区进行了测序，以描述微生物组的多样性和组成，并比较了用卫生纸或粪便采集的样本。我们的研究结果表明，这些采样方法提供了相似但不完全相同的微生物组图谱。基于卫生纸样本，我们发现微生物群落组成的大部分变化可以用个体身份来解释（使用不同的β多样性指标解释了 45-61%的变化），性别或地理位置（努勒维特或蒙特利尔）解释了很小但显著的变化（3-5%）。与我们之前在一个时间点的研究不同，一年的采样显示，饮食解释了所有参与者中 11%的群落组成变化，在努勒维特参与者中解释了 17%的变化。然而，我们没有观察到来自努勒维特或蒙特利尔的参与者的微生物组有明显的季节性变化。努勒维特参与者的个体内部微生物多样性随时间的波动比蒙特利尔更大，这与努勒维特更具变异性和高度个体化的饮食一致。
总之，这些结果表明，传统的因纽特饮食和生活方式对因纽特肠道微生物组的组成、多样性和稳定性有影响，即使饮食的季节性不如预期明显，这可能是由于饮食越来越西方化。
