Search resultsPhenolic acids from beer are absorbed and extensively metabolized in humans
Title
Phenolic acids from beer are absorbed and extensively metabolized in humans
Publication type
Journal Article
Year of Publication
2006
Authors
Journal
Journal of Nutritional Biochemistry
Volume
17
Issue
1
Pagination
14 - 22
Date published
2006
ISBN
09552863 (ISSN)
Keywords
4 hydroxyphenylacetic acid, absorption, Adult, article, beer, beverage, blood sampling, caffeic acid, Caffeic Acids, chemical structure, controlled study, Coumaric Acids, Female, ferulic acid, Gastrointestinal Tract, glucuronide, Glucuronides, human, Human plasma, Humans, Hydroxybenzoic Acids, ingestion, male, metabolism, phenol derivative, Phenolic acids, prevalence, reaction time, sinapic acid, statistical significance, sulfate, Sulfates, vanillic acid
Abstract
In spite of the wide literature describing the biological effects of phenolic compounds, scarce data are available on their absorption from diet. In the present work, we studied the absorption in humans of phenolic acids from beer, a common beverage rich in different phenolic acids with related chemical structures. Beer was analyzed for free and total (free+bound) phenolic acids. Ferulic, caffeic and sinapic acids were present in beer mainly as bound forms, while 4-hydroxyphenylacetic acid and p-coumaric acid were present mainly as free forms. Vanillic acid was present equally in the free and bound forms. Plasma samples were collected before and 30 and 60 min after beer administration and analyzed for free and conjugated phenolic acid content. A significant two- to fourfold increase in plasma levels of phenolic acids was detected with peak concentrations at 30 min after beer ingestion. 4-Hydroxyphenylacetic acid was present in plasma mainly as nonconjugated forms while p-coumaric acid was present equally as nonconjugated and conjugated forms. Ferulic, vanillic and caffeic acids were present in plasma predominantly as conjugated forms, with a slight prevalence of sulfates with respect to glucuronates. Our results indicate that phenolic acids from beer are absorbed from the gastrointestinal tract and are present in blood after being largely metabolized to the form of glucuronide and sulfate conjugates. The extent of conjugation is related to the chemical structure of phenolic acids: the monohydroxy derivatives showing the lowest conjugation degree and the dihydroxy derivatives showing the highest one.