Polyphenols is a major group of non-nutrients, considering their diversity, occurrence, and biological properties. Polyphenols play essential roles in the prevention of chronic diseases through the mitigation of inflammation, commonly referred to as meta-flammation. Inflammation is the most common feature of chronic diseases such as cancers, cardiovascular disorders, diabetes, and obesity. This aim of this review was to present a wide spectrum of literature data, including the current understanding of the role of polyphenols in the prevention and management of chronic diseases and their ability to interact with other food compounds in food systems. The publications cited are based on animal models, cohort studies, case controls, and feeding experiments. The significant effects of dietary polyphenols in cancers and cardiovascular diseases are evaluated. The interactive possibilities of dietary polyphenols with other dietary food compounds in food systems and their effects are also presented. However, despite several works, estimation of dietary intake is still inconclusive and a major challenge.
Dietary polyphenols including phenolic acids, flavonoids, catechins, tannins, lignans, stilbenes, and anthocyanidins are widely found in grains, cereals, pulses, vegetables, spices, fruits, chocolates, and beverages like fruit juices, tea, coffee and wine. In recent years, dietary polyphenols have gained significant interest among researchers due to their potential chemopreventive/protective functions in the maintenance of human health and diseases. It is believed that dietary polyphenols/flavonoids exert powerful antioxidant action for protection against reactive oxygen species (ROS)/cellular oxidative stress (OS) towards the prevention of OS-related pathological conditions or diseases.
Pre-clinical and clinical evidence strongly suggest that long term consumption of diets rich in polyphenols offer protection against the development of various chronic diseases such as neurodegenerative diseases, cardiovascular diseases (CVDs), cancer, diabetes, inflammatory disorders and infectious illness. Increased intake of foods containing polyphenols (for example, quercetin, epigallocatechin-3-gallate, resveratrol, cyanidin etc.) has been claimed to reduce the extent of a majority of chronic oxidative cellular damage, DNA damage, tissue inflammations, viral/bacterial infections, and neurodegenerative diseases.
It has been suggested that the antioxidant activity of dietary polyphenols plays a pivotal role in the prevention of OS-induced human diseases. In this narrative review, the biological/pharmacological significance of dietary polyphenols in the prevention of and/or protection against OS-induced major human diseases such as cancers, neurodegenerative diseases, CVDs, diabetes mellitus, cancer, inflammatory disorders and infectious diseases have been delineated.
This review specifically focuses a current understanding on the dietary sources of polyphenols and their protective effects including mechanisms of action against various major human diseases.
We assessed, for the first time, to what extent the composition of the gut microbiome might explain the cross-sectional association of habitual flavonoid and flavonoid-rich food intake with systolic and diastolic blood pressure (BP) in a community-based sample (N=904) from Northern Germany. Gut microbiome composition was sequenced from 16S ribosomal RNA genes. Higher total flavonoid intakes and specifically the polymer subclass were associated with lower systolic BP (SBP; β T3-T1: −2.9% [95% CI, −5.1 to −0.7], P=0.01 and −3.7% [95% CI, −5.4 to −1.0], P=0.01). In food-based analyses, a higher intake of berries (SBP, β Q4-Q1: −2.9% [95% CI, −5.2 to −0.6], P=0.01; pulse pressure, −5.5% [95% CI, −9.6 to −1.2], P=0.01) and red wine (SBP, β Q4-Q1: −2.6% [95% CI, −4.8 to −0.3], P=0.03; pulse pressure, −6.1% [95% CI, −10.1 to −2.0], P<0.01) were associated with lower SBP and pulse pressure. There were no associations with diastolic BP. In food-based analyses, higher intakes of anthocyanin-rich berries and red wine were associated with higher alpha diversity (β Q4-Q1: 0.03 [95% CI, 0.0–0.1], P=0.04 and 0.1 [95% CI, 0.03–0.1], P<0.01). Higher intakes of berries and apples/pears were associated with a lower abundance of Parabacteroides (β Q4-Q1: −0.2 [95% CI, −0.4 to −0.1], P<0.01, Q=0.07 and −0.3 [95% CI, −0.4 to −0.1], P< 0.01, Q=0.04). Structural equation modeling of these novel data suggests that microbial factors explained 15.2% to the association between flavonoid-rich foods and clinically relevant lower SBP. Further research should focus on interindividual variability in the gut microbiome in mediating the cardiovascular effects of flavonoid-rich foods.
We assessed, for the first time, to what extent the composition of the gut microbiome might explain the cross-sectional association of habitual flavonoid and flavonoid-rich food intake with systolic and diastolic blood pressure (BP) in a community-based sample (N=904) from Northern Germany. Gut microbiome composition was sequenced from 16S ribosomal RNA genes. Higher total flavonoid intakes and specifically the polymer subclass were associated with lower systolic BP (SBP; β T3-T1: −2.9% [95% CI, −5.1 to −0.7], P=0.01 and −3.7% [95% CI, −5.4 to −1.0], P=0.01). In food-based analyses, a higher intake of berries (SBP, β Q4-Q1: −2.9% [95% CI, −5.2 to −0.6], P=0.01; pulse pressure, −5.5% [95% CI, −9.6 to −1.2], P=0.01) and red wine (SBP, β Q4-Q1: −2.6% [95% CI, −4.8 to −0.3], P=0.03; pulse pressure, −6.1% [95% CI, −10.1 to −2.0], P<0.01) were associated with lower SBP and pulse pressure. There were no associations with diastolic BP. In food-based analyses, higher intakes of anthocyanin-rich berries and red wine were associated with higher alpha diversity (β Q4-Q1: 0.03 [95% CI, 0.0–0.1], P=0.04 and 0.1 [95% CI, 0.03–0.1], P<0.01). Higher intakes of berries and apples/pears were associated with a lower abundance of Parabacteroides (β Q4-Q1: −0.2 [95% CI, −0.4 to −0.1], P<0.01, Q=0.07 and −0.3 [95% CI, −0.4 to −0.1], P< 0.01, Q=0.04). Structural equation modeling of these novel data suggests that microbial factors explained 15.2% to the association between flavonoid-rich foods and clinically relevant lower SBP. Further research should focus on interindividual variability in the gut microbiome in mediating the cardiovascular effects of flavonoid-rich foods.