2017年8月25日，美國科學促進會《科學》封面發(fā)表美國斯坦福大學、德克薩斯人類食物工程、圣迭戈加利福尼亞大學、紐約大學、英國倫敦大學國王學院、圣托馬斯醫(yī)院、加拿大西安大略大學、坦桑尼亞國家醫(yī)學研究所的研究報告，發(fā)現(xiàn)坦桑尼亞狩獵采集者的腸道菌群組成會隨著他們食物的季節(jié)變化而改變，他們腸道微生物組的成分也與那些吃西方飲食者大相徑庭。
哈扎人是非洲剩下的以狩獵采集方式生活的最后一批人，堅持這種傳統(tǒng)生活方式的人已經(jīng)不到200人。他們的飲食因季節(jié)而異：在潮濕的雨節(jié)，他們會更經(jīng)常地覓食漿果和吃蜂蜜；他們在干旱季節(jié)的狩獵則最為成功。為更好地了解飲食與微生物組之間的關(guān)系模式，該研究在不同季節(jié)收集了來自188個哈扎人的350個糞便樣本及飲食數(shù)據(jù)。
結(jié)果發(fā)現(xiàn)，在干旱季節(jié)結(jié)束至潮濕季節(jié)開始之間的這段時間，他們糞便中70%的擬桿菌類消失了，但是這些細菌主體會在較后時間點重新出現(xiàn)。在哈扎人的糞便中總共發(fā)現(xiàn)了4個科的細菌尤其會隨季節(jié)而改變。接著，該研究將哈扎人的腸道微生物組與16個國家18個人群的微生物組進行了比較，工業(yè)化地區(qū)人群的腸道微生物組由擬桿菌占主導，在微生物組中的平均比例達21%，而該比例在吃傳統(tǒng)食物人群中為0.8%；同樣，在哈扎人和其他進食傳統(tǒng)食物人群中的2種普遍存在的細菌，在進食非傳統(tǒng)食物的人群中罕見或完全無法檢測到。哈扎人還比進食西方飲食的人有更多的用于加工植物碳水化合物的酶。美國人群的腸道菌群要比哈扎人的菌群展現(xiàn)出大幅增多的對抗生素有抵抗力的基因。
因此，隨著寒來暑往、秋收冬藏，不同季節(jié)飲食結(jié)構(gòu)的變化可導致腸道菌群功能的相應變化，進而影響到腸道菌群組成。
對此，美國國家環(huán)境衛(wèi)生科學研究所發(fā)表同期評論：腸道的季節(jié)變化。
Science. 2017 Aug 25;357(6353):802-806.
Seasonal cycling in the gut microbiome of the Hadza hunter-gatherers of Tanzania.
Samuel A. Smits1, Jeff Leach, Erica D. Sonnenburg, Carlos G. Gonzalez, Joshua S. Lichtman, Gregor Reid, Rob Knight, Alphaxard Manjurano, John Changalucha, Joshua E. Elias, Maria Gloria Dominguez-Bello, Justin L. Sonnenburg.
Stanford University, Stanford, CA, USA; Human Food Project, Terlingua, TX, USA; King's College London, St. Thomas' Hospital, London, UK; Western University, London, Ontario, Canada; University of California, San Diego, CA, USA; National Institute for Medical Research, Mwanza, Tanzania; New York University, New York, NY, USA.
Seasonal diets, seasonal microbiota
Among the Hadza of western Tanzania, a few hundred people still live in small groups as hunter-gatherers, reliant solely on the wild environment for food. Smits et al. found that the microbiota of these people reflects the seasonal availability of different types of food (see the Perspective by Peddada). Between seasons, striking differences were observed in their gut microbial communities, with some taxa apparently disappearing, only to reappear when the seasons turned. Further comparison of the Hadza microbiota with that of diverse urbanized peoples revealed distinctly different patterns of microbial community composition.
Although humans have cospeciated with their gut-resident microbes, it is difficult to infer features of our ancestral microbiome. Here, we examine the microbiome profile of 350 stool samples collected longitudinally for more than a year from the Hadza hunter-gatherers of Tanzania. The data reveal annual cyclic reconfiguration of the microbiome, in which some taxa become undetectable only to reappear in a subsequent season. Comparison of the Hadza data set with data collected from 18 populations in 16 countries with varying lifestyles reveals that gut community membership corresponds to modernization: Notably, the taxa within the Hadza that are the most seasonally volatile similarly differentiate industrialized and traditional populations. These data indicate that some dynamic lineages of microbes have decreased in prevalence and abundance in modernized populations.
DOI: 10.1126/science.aan4834
Science. 2017 Aug 25;357(6353):754-755.
Seasonal change in the gut: The gut microbiome of Hadza hunter-gatherers changes with the season.
Shyamal Peddada.
National Institute of Environmental Health Sciences, Durham, N, USA.
We live in a dynamic environment where diet, weather, social interactions, lifestyles, and a host of other factors change on a regular basis. Consequently, the microbial composition of even a healthy person's gut is subject to natural variations; however, not much is known about these variations. On page 802 of this issue, Smits et al. study seasonal changes in the gut microbiome of the Hadza population (see the photo), a hunter-gatherer community residing near Lake Eyasi in Tanzania, Africa, during the wet and dry seasons of 2013 and 2014. Using a new methodology, they identify operational taxonomic units (OTUs)—clusters of reads that are a proxy for taxons—that respond to seasonal changes in diet, activity, and the external environment, thereby maintaining a healthy gut.
DOI: 10.1126/science.aao2997
