The gut microbiome describes the complex community of microorganisms that populate the gastrointestinal tract. Gut microbes in the large bowel utilise both dietary-derived nutrients, such as host-indigestible carbohydrates (fibre) and excess protein, host-derived nutrients (intestinal mucin), and also interact with the by-products of digestion such as bile acids. They transform these compounds into a series of metabolites that can profoundly shape host physiology both locally and systemically. These metabolites can fundamentally alter host outcomes, promoting either gut health, or sub-optimal conditions in the gut that contribute to poor health, including increased risk of cancer. The microbiome of an individual has also been shown to impact response to cancer treatment strategies, including both treatment efficacy and side-effects in the gut and more systemically. This makes the microbiome a powerful potential tool for therapeutic purposes, once we overcome the challenges associated with individual variation in microbial community composition. As the gut microbial ecosystem is primarily altered by nutrient availability, diet therefore represents an important asset in therapeutically altering the gut microbiome.

肠道微生物组描述了分布在胃肠道中的复杂微生物群落。大肠中的肠道微生物利用膳食来源的营养素，如宿主不可消化的碳水化合物（纤维）和过量蛋白质、宿主来源的营养素（肠道粘蛋白），还与消化副产物（如胆汁酸）相互作用。它们将这些化合物转化为一系列代谢物，这些代谢物可以在局部和全身性方面深刻地塑造宿主的生理机能。这些代谢物可以从根本上改变宿主结果，促进肠道健康，或导致肠道健康状况不佳，包括增加患癌症的风险。个体的微生物组也已被证明会影响对癌症治疗策略的反应，包括治疗功效和肠道副作用，以及更全身性的副作用。一旦我们克服了与微生物群落组成的个体差异相关的挑战，这将使微生物组成为用于治疗目的的强大潜在工具。由于肠道微生物生态系统主要受营养成分的影响，因此饮食是治疗改变肠道微生物组的重要资产。