Polyphenols and health: Interactions between fibre, plant polyphenols and the gut microbiota

Abstract

A high‐fibre diet and one rich in fruit and vegetables have long been associated with lower risk of chronic disease. There are several possible mechanisms underpinning these associations, but one likely important factor is the production of bioactive molecules from plant‐based foods by the bacteria in the colon. This links to our growing understanding of the role of the gut microbiome in promoting health. Polyphenolic‐rich plant foods have been associated with potential health effects in many studies, but the bioavailability of polyphenol compounds, as eaten, is often very low. Most of the ingested molecules enter the large intestine where they are catabolised to smaller phenolic acids that may be the key bioactive effectors. Dietary fibres, present in plant foods, are also fermented by the bacteria to short‐chain fatty acids, compounds associated with several beneficial effects on cell turnover, metabolism and eating behaviour. Polyphenols and fibre are often eaten together, but there is a lack of research investigating the interaction between these two groups of key substrates for the colonic bacteria. In a project funded by the Biotechnology and Biological Sciences Research Council Diet and Health Research Industry Club, we are investigating whether combining different fibres and polyphenol sources can enhance the production of bioactive phenolic acids to promote health. This could lead to improved dietary recommendations and to new products with enhanced potential health‐promoting actions.

Hydroxycinnamic acids and human health: recent advances

“…[208][209][210][211][212][213] Considering the above, the human gut microbiota has recently become a therapeutic target against diet-related diseases. 214,215 Among targeting agents, polyphenols have been studied recently in relation to their reciprocal interactions with the gut microbiota, [216][217][218][219][220][221] while considering their potential antioxidant, anticarcinogenic or antimicrobial properties. 19,21,22 However, the in vivo evidence is still scarce, and more studies are needed to clarify the relationship between dietary phenolics and the gut microbiota.…”

“…19,21,22 However, the in vivo evidence is still scarce, and more studies are needed to clarify the relationship between dietary phenolics and the gut microbiota. 218,221 Hydroxycinnamic acids and their influence on the gut microbiota To modulate the composition and consequently the biological activity of the human gut microbiota, the dietary strategies involving the three 'P's -probiotics, prebiotics and polyphenols -are amongst the most well established. 214 Polyphenols, a large class of plant metabolites, have been extensively studied over the past two decades in connection with their role in protection against diet-related diseases.…”

Prebiotics – an added benefit of some fibre types

“…polyphenols), some of which can nourish gut microbes (Conlon & Bird 2014) and may confer other health benefits (Williamson 2017). Interestingly, emerging research suggests that dietary fibre may enhance the bioavailability of polyphenols in the gastrointestinal tract, both directly through mechanisms that occur as a result of co-ingestion and also indirectly by stimulating the growth of bacterial species that catabolise phenolic compounds (Edwards et al 2017). It is also possible that dietary prebiotic content has an impact on the changes in gut microbial composition and SCFA production that have been noted in the above studies, but this has not yet been assessed.…”

Extraction and Electrochemical Analysis of Polyphenols in Plant Samples

“…Tea polyphenols, a type of polyphenols extracted from tea, are used to preserve cooked foods, as they can inhibit the reproduction of microorganisms and extend the shelf life of food. In the study of chicken nutrition, catechins have antioxidant effects similar to natural vitamin E, and the storage time of frozen chicken can be improved by feeding diets supplemented with catechins [45][46][47][48][49][50][51].…”