Current explorations of nutrition and the gut microbiome: a comprehensive evaluation of the review literature

CONTEXT: The ability to measure the gut microbiome led to a surge in understanding and knowledge of its role in health and disease. The diet is a source of fuel for and influencer of composition of the microbiome. OBJECTIVE: To assess the understanding of the interactions between nutrition and the gut microbiome in healthy adults. DATA SOURCES: PubMed and Google Scholar searches were conducted in March and August 2018 and were limited to the following: English, 2010-2018, healthy adults, and reviews. DATA EXTRACTION: A total of 86 articles were independently screened for duplicates and relevance, based on preidentified inclusion criteria. DATA ANALYSIS: Research has focused on dietary fiber - microbiota fuel. The benefits of fiber center on short-chain fatty acids, which are required by colonocytes, improve absorption, and reduce intestinal transit time. Contrastingly, protein promotes microbial protein metabolism and potentially harmful by-products that can stagnate in the gut. The microbiota utilize and produce micronutrients; the bidirectional relationship between micronutrition and the gut microbiome is emerging. CONCLUSIONS: Nutrition has profound effects on microbial composition, in turn affecting wide-ranging metabolic, hormonal, and neurological processes. There is no consensus on what defines a "healthy" gut microbiome. Future research must consider individual responses to diet.