Bioavailability and bioefficacy of polyphenols in humans. I. Review of 97 bioavailability studies
01 Jan 2005-The American Journal of Clinical Nutrition (American Society for Nutrition)-Vol. 81, Iss: 1, pp 230-242
TL;DR: Gallic acid and isoflavones are the most well-absorbed polyphenols, followed by catechins, flavanones, and quercetin glucosides, but with different kinetics, and the least well- absorption polyphenol are the proanthocyanidins, the galloylated tea catech ins, andThe anthocyanins.
About: This article is published in The American Journal of Clinical Nutrition.The article was published on 2005-01-01 and is currently open access. It has received 3534 citations till now. The article focuses on the topics: Health effects of natural phenols and polyphenols & Dietary Polyphenol.
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TL;DR: Phenolic compounds, ubiquitous in plants are an essential part of the human diet, and are of considerable interest due to their antioxidant properties as mentioned in this paper, and their structures may range from a simple phenolic molecule to a complex high-molecular weight polymer.
2,723 citations
TL;DR: It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how (poly)phenol molecules interact with human physiological and pathological processes.
Abstract: Human intervention trials have provided evidence for protective effects of various (poly)phenol-rich foods against chronic disease, including cardiovascular disease, neurodegeneration, and cancer. While there are considerable data suggesting benefits of (poly)phenol intake, conclusions regarding their preventive potential remain unresolved due to several limitations in existing studies. Bioactivity investigations using cell lines have made an extensive use of both (poly)phenolic aglycones and sugar conjugates, these being the typical forms that exist in planta, at concentrations in the low-μM-to-mM range. However, after ingestion, dietary (poly)phenolics appear in the circulatory system not as the parent compounds, but as phase II metabolites, and their presence in plasma after dietary intake rarely exceeds nM concentrations. Substantial quantities of both the parent compounds and their metabolites pass to the colon where they are degraded by the action of the local microbiota, giving rise principally to small phenolic acid and aromatic catabolites that are absorbed into the circulatory system. This comprehensive review describes the different groups of compounds that have been reported to be involved in human nutrition, their fate in the body as they pass through the gastrointestinal tract and are absorbed into the circulatory system, the evidence of their impact on human chronic diseases, and the possible mechanisms of action through which (poly)phenol metabolites and catabolites may exert these protective actions. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.
1,968 citations
Cites background from "Bioavailability and bioefficacy of ..."
...The differing levels of excretion of hesperetin and naringenin metabolites, relative to the amounts ingested, is a trend that has been observed in some, but not all, flavanone-feeding studies (291)....
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...A study in which ileostomists consumed apple juice indicates that most pass unaltered to the large intestine (233), where they are catabolized by the colonic microbiota, yielding a diversity of phenolic acids and aromatic components (133, 291), including 3-(3¢-hydroxyphenyl)propionic acid and 4-O-methyl-gallic acid (111, 156), which are absorbed into the circulatory system and excreted in the urine....
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TL;DR: This review summarizes the chemistry, biosynthesis and occurrence of the compounds involved, namely the C6-C3-C6 flavonoids-anthocyanins, dihydrochalcones, Flavan-3-ols, flavanones, flavones, Flavonols and isoflavones, and the mechanisms underlying these processes are discussed.
1,728 citations
TL;DR: The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens.
Abstract: Relation between the gut microbiota and human health is being increasingly recognised It is now well established that a healthy gut flora is largely responsible for overall health of the host The normal human gut microbiota comprises of two major phyla, namely Bacteroidetes and Firmicutes Though the gut microbiota in an infant appears haphazard, it starts resembling the adult flora by the age of 3 years Nevertheless, there exist temporal and spatial variations in the microbial distribution from esophagus to the rectum all along the individual's life span Developments in genome sequencing technologies and bioinformatics have now enabled scientists to study these microorganisms and their function and microbe-host interactions in an elaborate manner both in health and disease The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens Several factors play a role in shaping the normal gut microbiota They include (1) the mode of delivery (vaginal or caesarean); (2) diet during infancy (breast milk or formula feeds) and adulthood (vegan based or meat based); and (3) use of antibiotics or antibiotic like molecules that are derived from the environment or the gut commensal community A major concern of antibiotic use is the long-term alteration of the normal healthy gut microbiota and horizontal transfer of resistance genes that could result in reservoir of organisms with a multidrug resistant gene pool
1,602 citations
TL;DR: The mechanism by which quercetin may operate as an antioxidant as well as the potential use of this antioxidant as a nutraceutical (tested both ex vivo and in vivo) will be discussed.
1,598 citations
Cites background from "Bioavailability and bioefficacy of ..."
...This indicates that, upon repeated quercetin supplementation, they could attain a considerable plasma level (Hollman et al., 1997; Manach et al., 2005)....
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References
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TL;DR: The nature and contents of the various polyphenols present in food sources and the influence of agricultural practices and industrial processes are reviewed, and bioavailability appears to differ greatly between the variousPolyphenols, and the most abundantpolyphenols in the authors' diet are not necessarily those that have the best bioavailability profile.
6,842 citations
"Bioavailability and bioefficacy of ..." refers background in this paper
...The biochemical explanation for the better absorption of quercetin glucosides has been discussed elsewhere (1)....
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...The chemical structures and the food contents of the various polyphenols have been reviewed elsewhere (1)....
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TL;DR: It is time to rethink the design of in vitro and in vivo studies, so that these issues are carefully considered, and the length of human intervention studies should be increased, to more closely reflect the long-term dietary consumption of polyphenols.
1,409 citations
"Bioavailability and bioefficacy of ..." refers background in this paper
...In addition, the consumption of proanthocyanidin-rich foods, such as cocoa, red wine, or grape seed extracts, has been shown to increase the plasma antioxidant capacity, to have positive effects on vascular function, and to reduce platelet activity in humans (97)....
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TL;DR: The use of new analytic technology suggests that in the past flavonoid intake has been overestimated fivefold, but on a milligram-per-day basis, the intake of the antioxidant flavonoids still exceeded that of the antioxidants beta-carotene and vitamin E.
Abstract: Flavonoids are strong antioxidants that occur naturally in foods and can inhibit carcinogenesis in rodents. Accurate data on population-wide intakes of flavonoids are not available. Here, using data of the Dutch National Food Consumption Survey 1987-1988, we report the intake of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin among 4,112 adults. The flavonoid content of vegetables, fruits, and beverages was determined by high-performance liquid chromatography. In all subjects, average intake of all flavonoids combined was 23 mg/day. The most important flavonoid was the flavonol quercetin (mean intake 16 mg/day). The most important sources of flavonoids were tea (48% of total intake), onions (29%), and apples (7%). Flavonoid intake did not vary between seasons; it was not correlated with total energy intake (r = 0.001), and it was only weakly correlated with the intake of vitamin A (retinol equivalents, r = 0.14), dietary fiber (r = 0.21), and vitamin C (r = 0.26). Our use of new analytic technology suggests that in the past flavonoid intake has been overestimated fivefold. However, on a milligram-per-day basis, the intake of the antioxidant flavonoids still exceeded that of the antioxidants beta-carotene and vitamin E. Thus flavonoids represent an important source of antioxidants in the human diet.
1,237 citations
TL;DR: It is now apparent that there are two distinct subpopulations of people and that "bacterio-typing" individuals for their ability to make equol may hold the clue to the effectiveness of soy protein diets in the treatment or prevention of hormone-dependent conditions.
Abstract: Equol [7-hydroxy-3-(4'-hydroxyphenyl)-chroman] is a nonsteroidal estrogen of the isoflavone class. It is exclusively a product of intestinal bacterial metabolism of dietary isoflavones and it possesses estrogenic activity, having affinity for both estrogen receptors, ERalpha and ERbeta. Equol is superior to all other isoflavones in its antioxidant activity. It is the end product of the biotransformation of the phytoestrogen daidzein, one of the two main isoflavones found in abundance in soybeans and most soy foods. Once formed, it is relatively stable; however, equol is not produced in all healthy adults in response to dietary challenge with soy or daidzein. Several recent dietary intervention studies examining the health effects of soy isoflavones allude to the potential importance of equol by establishing that maximal clinical responses to soy protein diets are observed in people who are good "equol-producers." It is now apparent that there are two distinct subpopulations of people and that "bacterio-typing" individuals for their ability to make equol may hold the clue to the effectiveness of soy protein diets in the treatment or prevention of hormone-dependent conditions. In reviewing the history of equol, its biological properties, factors influencing its formation and clinical data, we propose a new paradigm. The clinical effectiveness of soy protein in cardiovascular, bone and menopausal health may be a function of the ability to biotransform soy isoflavones to the more potent estrogenic isoflavone, equol. The failure to distinguish those subjects who are "equol-producers" from "nonequol producers" in previous clinical studies could plausibly explain the variance in reported data on the health benefits of soy.
1,143 citations
"Bioavailability and bioefficacy of ..." refers background in this paper
...” Equol producers may gain more benefits from soy consumption than do nonproducers (119, 120)....
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...estrogenic than its precursor daidzein in many in vitro studies and in animal models (119)....
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TL;DR: It is concluded that humans absorb appreciable amounts of quercetin and that absorption is enhanced by conjugation with glucose.
934 citations
"Bioavailability and bioefficacy of ..." refers background in this paper
...Twenty years after Gugler et al (23, 24) failed to find quercetin in plasma or urine from volunteers challenged with 4 g pure aglycone, the team of Hollman et al (23, 24) showed that quercetin was indeed absorbed in humans....
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