Dietary hydroxybenzoic acid derivatives - nature, occurrence and dietary burden

Quantitative data for hydroxybenzoic acids (naturally occurring and permitted additives) and their conjugates in foods and beverages are summarised. Tea, rosaceous fruits, red wines and potatoes are important sources for which more comprehensive compositional data are required. Their absorption, metabolism, toxicological evaluation and possible biological significance are discussed. There are insufficient data to properly define the dietary burdens, but it would seem that ellagic acid and gallic acid from natural sources may dominate in many cases, although the intake of added benzoic acid may be of a similar magnitude. It is pointed out that an additional, previously overlooked and possibly significant burden, particularly of benzoic acid itself, might arise as a result of the gut flora metabolism of larger-mass dietary phenols.