Gut microbiota functions: metabolism of nutrients and other food components

Abstract

The diverse microbial community that inhabits the human gut has an extensive metabolic repertoire that is distinct from, but complements the activity of mammalian enzymes in the liver and gut mucosa and includes functions essential for host digestion. As such, the gut microbiota is a key factor in shaping the biochemical profile of the diet and, therefore, its impact on host health and disease. The important role that the gut microbiota appears to play in human metabolism and health has stimulated research into the identification of specific microorganisms involved in different processes, and the elucidation of metabolic pathways, particularly those associated with metabolism of dietary components and some host-generated substances. In the first part of the review, we discuss the main gut microorganisms, particularly bacteria, and microbial pathways associated with the metabolism of dietary carbohydrates (to short chain fatty acids and gases), proteins, plant polyphenols, bile acids, and vitamins. The second part of the review focuses on the methodologies, existing and novel, that can be employed to explore gut microbial pathways of metabolism. These include mathematical models, omics techniques, isolated microbes, and enzyme assays.

Annual Research Review: Critical windows – the microbiota–gut–brain axis in neurocognitive development

“…Perhaps the most parsimonious hypothesis to explain microbial modulation of neurodevelopment is that the microbiota is a key source of essential nutrients and energy for the growing brain. Certainly, the microbiota is known to convert food components that would otherwise be indigestible into products with nutritional or biological value (see Rowland et al, ; Sela & Mills, , for reviews on this topic, the latter in infants), and nutrition itself is a well‐established modulator of cognitive outcomes. Breastfeeding, a dietary factor that influences microbiota maturation (Ho et al, ), has long been purported to improve cognitive outcomes (Johnstone et al, ), although more recent data indicate that this effect is largely accounted for by confounding variables such as maternal intelligence or education levels (Walfisch et al, ).…”

Shifting Climates, Foods, and Diseases: The Human Microbiome through Evolution

“…[9,20,21] For instance, mammals do not possess endogenous cellulase, the enzyme required for the breakdown and digestion of dietary fiber. The gut microbiome influences host nutritional physiology and behavior, including facilitating the digestion of specific food sources that would otherwise be unusable to humans.…”

Advances in exploring equol production and application

“…Equol is mainly produced by intestinal bacteria in vivo after oral administration of daidzein and ( S )‐equol is the only form after intestinal bacteria enantiospecifically synthesized (Setchell, Brown, & Lydeking‐Olsen, ). As revealed by the relevant studies as low as 25%–30% of young people can excrete equol in vivo after consuming soy foods on a daily basis (Atkinson, Frankenfeld, & Lampe, ; Rowland et al, ). The frequency of “equol producers” in Western vegetarians, Japanese, Korean, and Chinese young people is 50%–60% (Setchell & Cole, ).…”