From gut microbiota to systemic health: Impact of diet in the bacterial ecosystem

Abstract

The gut microbiota plays a central role in maintaining host homeostasis through its involvement in nutrient metabolism, immune regulation, intestinal barrier integrity, and inter-organ communication. Alterations in microbial composition and function (dysbiosis) have been associated with a wide range of chronic conditions. Among dietary strategies targeting the gut ecosystem, probiotics (i.e., novel lactic acid bacteria, Faecalibacterium prausnitzii, Akkermansia muciniphila, Christensenella minuta, Hafnia alvei), prebiotics (i.e., inulin, β-glucans, resistant starch, fructo, galacto and xylo-oligosaccharides), postbiotics (i.e., extracellular vesicles, exopolysaccharides, lipoteichoic acids), and synbiotics have gained increasing attention due to their potential to restore microbial balance and promote systemic health. On the other hand, dietary habits are among the most important environmental factors shaping microbiota composition and functionality throughout life. This presentation reviews current evidence from observational studies, clinical trials, and mechanistic investigations addressing the relationship between diet, microbiota composition, microbial metabolism, and health outcomes. Additionally, it examines the effects of microbiota-directed nutritional strategies on microbial diversity, metabolite production, immune function, and disease-related biomarkers. Diets rich in fermented foods (i.e., kombucha, kefir, yogurt) and plant-based foods, dietary fiber, legumes, fruits, vegetables, and whole grains are consistently associated with greater microbial diversity and increased production of beneficial metabolites, such as short-chain fatty acids. Of special interest, polyphenols contribute to reshape the microbial ecosystem and help reverse dysbiosis, while the microbiota transforms many polyphenols into bioactive metabolites that exert systemic effects. There are examples of pomegranate ellagitannins, green tea catechins, cocoa flavanols, and berry anthocyanins. On the other hand, dietary patterns characterized by high intakes of ultra-processed foods, refined sugars, saturated fats, and low fiber content are linked to reduced microbial diversity, impaired gut barrier function, and chronic low-grade inflammation. Summing up, these are the three dietary pillars contributing to the restoration of eubiosis and amelioration of systemic health: fibers, fermented foods, and polyphenols.

The gut microbiota plays a central role in maintaining host homeostasis through its involvement in nutrient metabolism, immune regulation, intestinal barrier integrity, and inter-organ communication. Alterations in microbial composition and function (dysbiosis) have been associated with a wide range of chronic conditions. Among dietary strategies targeting the gut ecosystem, probiotics (i.e., novel lactic acid bacteria, Faecalibacterium prausnitzii, Akkermansia muciniphila, Christensenella minuta, Hafnia alvei), prebiotics (i.e., inulin, β-glucans, resistant starch, fructo, galacto and xylo-oligosaccharides), postbiotics (i.e., extracellular vesicles, exopolysaccharides, lipoteichoic acids), and synbiotics have gained increasing attention due to their potential to restore microbial balance and promote systemic health. On the other hand, dietary habits are among the most important environmental factors shaping microbiota composition and functionality throughout life. This presentation reviews current evidence from observational studies, clinical trials, and mechanistic investigations addressing the relationship between diet, microbiota composition, microbial metabolism, and health outcomes. Additionally, it examines the effects of microbiota-directed nutritional strategies on microbial diversity, metabolite production, immune function, and disease-related biomarkers. Diets rich in fermented foods (i.e., kombucha, kefir, yogurt) and plant-based foods, dietary fiber, legumes, fruits, vegetables, and whole grains are consistently associated with greater microbial diversity and increased production of beneficial metabolites, such as short-chain fatty acids. Of special interest, polyphenols contribute to reshape the microbial ecosystem and help reverse dysbiosis, while the microbiota transforms many polyphenols into bioactive metabolites that exert systemic effects. There are examples of pomegranate ellagitannins, green tea catechins, cocoa flavanols, and berry anthocyanins. On the other hand, dietary patterns characterized by high intakes of ultra-processed foods, refined sugars, saturated fats, and low fiber content are linked to reduced microbial diversity, impaired gut barrier function, and chronic low-grade inflammation. Summing up, these are the three dietary pillars contributing to the restoration of eubiosis and amelioration of systemic health: fibers, fermented foods, and polyphenols.