The Impact Of Different Dietary Habits In Shaping Human Gut Microbiome

Background and aimsHuman gut microbiome is shaped by multiple environmental factors,and diet is one of the most important determinant in the composition of gut microbiota.With the popularization of westernized diet and the acceleration of urbanization,our dietary habits have changed dramatically,with more and more young men consuming high salt and meat.Meanwhile,with the understanding of healthy eating,the global market of yogurt consumption is expanding.Previous studies have also found that dietary habits such as high salt and high meat consumption are positively correlated with many diseases such as hypertension,obesity and colon cancer,part of mechanisms is changes of gut microbiota composition.However,it remains unclear for the causal relationships and mechanism between long-term dietary habits and intestinal microbiome in healthy adults.Therefore,we aimed to investigate the influence of high salt,dietary fiber and the frequency of yogurt intake in long-term diet on intestinal microbiota and the changes of relevant signaling pathways.Methods101 healthy adults aged 18 to 70 years old were enrolled for this study from December 2016 to May 2018,and a food frequency questionnaire about long-term dietary habits,lifestyle and anthropometric factors was filled in truthfully by each volunteer.The fecal samples were collected and stored at-80?,from which total bacteria DNA was extracted.The fecal microbiota of the 101 samples was characterized by Illumina sequencing of the V3-V4 region of the bacteria 16S rRNA gene.The effects of high-salt diet and normal-salt diet,animal-based diet and plant-based diet,and different frequencies of yogurt intake on intestinal microbiota were explored according to the food frequency questionnaires of the subjects,and the changes of related signaling pathways were predicted.ResultsNo significant differences were observed in baseline characteristics.Unlike the results from the normal-salt diet group(no more than 6g NaCl per day),the abundance of short chain fatty acids(SCFA)-producing genus Faecalibacterium with anti-inflammatory effect,beneficial bacteria Bifidobacterium and Lactobacillus was decreased,Fusobacterium associated with colorectal cancer and cholesterol-metabolized bacterium Parasutterella was increased,however,in the high-salt diet group(more than 6g NaCl per day).The ubiquitin system and lysosome pathways were significantly activated in the high-salt diet group.We reported that a higher intake frequencies of vegetables and fruits(plant-based diet)was associated with increased abundance of genus Faecalibacterium,polysaccharides-metabolized genus Lachnospira and Bifidobacterium,which were considered to benefit the gut health.Reduced ratio of Firmicutes/Bacteroidetes was detected in plant-based diet group compared with animal-based diet group(A higher intake frequencies of meat than vegetables and fruits).The N-glycan biosynthesis pathway was significantly activated in plant-based diet group.Based on the analyses of gut microbiota community for four different yogurt-intake levels(none,less,some,more),we investigated that observed richness of the community was higher while more frequent yogurt was taken.Our results demonstrated that more yogurt-intake was correlated with increased abundance of Subdoligranulum,Dialister,Faecalibacterium,Bifidobacterium,thus profiting to gut health.The pathways of amino acid metabolism,biosynthesis and degradation and Prion disease pathway were significantly activated in none yogurt-intake group comparing with more yogurt-intake groupConclusionsAs such,dietary habits alter the composition of gut microbiota and affect the metabolic pathways of bacteria.More frequencies of yogurt intake may contribute to the gut health,while animal based diet and higher intakes of salt may have influence adversely on intestional environment via elevated detrimental bacteria and decreased beneficial bacteria,thus affecting the gut metabolism.