The effects of polyphenols and other bioactives on human health.
Fraga CG, Croft KD, Kennedy DO, Tomás-Barberán FA
Food Funct. Feb 2019. doi: 10.1039/c8fo01997e
COMMENT: The aim of this review is to explore how polyphenols exert health benefits in humans, and the role of gut microbiota in their metabolism to generate active metabolites. The polyphenols are a group of compounds found in plants. Food sources rich in polyphenols are tea, cocoa, coffee, fruits and vegetables.
A proportion of dietary polyphenols are metabolized by the large intestine microbiota to form absorbable compounds.
The ability of individuals to metabolize certain polyphenols has been attributed to distinct phenotypes (i.e. metabotypes).
Metabolism based on the types of bacteria that are present in the colon, can lead to differing biological effects.
Some polyphenols can inhibit the growth of detrimental bacteria or stimulate growth of beneficial bacteria. It has been suggested that the relationship between polyphenols and the microbiome of the human gut mimics to some extent the relationship between polyphenols and pathogenic and symbiotic microbial population in the plants roots.
The review summarizes the evidence of positive effects of polyphenols on cardiometabolic health and cognitive functioning. However, the mechanisms of action and the amounts of these compounds that need to be consumed to provide positive health effects need to be further investigated.
Consuming polyphenol-rich foods has been associated with a range of health benefits, including optimizing cardiometabolic health and to a lesser extent positively impacting brain functioning in humans. However, the actual mechanisms for these effects have not been fully established.
The complex relationships between polyphenols and the gut microbiome, as well as the interaction between the microbiome and health outcomes, should be considered as relevant participants in these health effects that warrant further research.
Furthermore, the possibility of interactions with other bioactives present in foods or that can be administered as supplements, (e.g. fiber, terpenoids, and alkaloids) deserves consideration when designing future studies.