White wine phenolics are absorbed and extensively metabolized in humans

Despite the vast literature describing the biological effects of phenolic compounds, rather scarce data are available on their absorption from diet in humans. The present study focused on the absorption in humans of phenolic acids from white wine, particularly hydroxycinnamic acids and their esters with tartaric acid. The results obtained indicate that, following a single wine drink, hydroxycinnamic acids from white wine are absorbed from the gastrointestinal tract and circulate in the blood after being largely metabolized to the form of glucuronide and sulfate conjugates. Unmodified tartaric acid esters of hydroxycinnamic acids from wine are present in human plasma at low levels, if any. Wine hydroxycinnamic acids, although present in wine as conjugated forms, are still bioavailable to humans.