Quercetin is a dietary antioxidant that prevents oxidation of low-density lipoproteins in vitro. Intake of quercetin was inversely associated with coronary heart disease mortality in elderly Dutch men. However, the extent of absorption of quercetin in humans is unclear. The aim of this study was to quantify absorption of various forms of quercetin. Nine healthy ileostomy subjects were studied, to avoid losses caused by colonic bacteria. They followed a quercetin-free diet for 12 d; on days 4, 8, and 12 they received a supplement of fried onions at breakfast (rich in quercetin glucosides) equivalent to 89 mg aglycone, pure quercetin rutinoside (the major quercetin compound in tea) equivalent to 100 mg aglycone, or 100 mg pure quercetin aglycone, in random order. Subsequently, participants collected ileostomy effluent and urine for 13 h. In vitro incubations of quercetin or its glycosides with gastrointestinal fluids showed minimal degradation. Absorption of quercetin, defined as oral intake minus ileostomy excretion and corrected for 14% degradation within the ileostomy bag, was 52 +/- 15% for quercetin glucosides from onions, 17 +/- 15% for quercetin rutinoside, and 24 +/- 9% for quercetin aglycone. Mean excretion of quercetin or its conjugates in urine was 0.5% of the amount absorbed; quercetin excretion in urine was negatively correlated with excretion in ileostomy effluent (r = -0.78, n = 27). We conclude that humans absorb appreciable amounts of quercetin and that absorption is enhanced by conjugation with glucose.

Quercetin is a strong antioxidant and a major dietary flavonoid. Epidemiological studies suggest that consumption of quercetin protects against cardiovascular disease, but its absorption in man is controversial. We fed nine subjects a single large dose of onions, which contain glucose conjugates of quercetin, apples, which contain both glucose and non-glucose quercetin glycosides, or pure quercetin-3-rutinoside, the major quercetin glycoside in tea. Plasma levels were then measured over 36 h. Bioavailability of quercetin from apples and of pure quercetin rutinoside was both 30% relative to onions. Peak levels were achieved less than 0.7 h after ingestion of onions, 2.5 h after apples and 9 h after the rutinoside. Half-lives of elimination were 28 h for onions and 23 h for apples. We conclude that conjugation with glucose enhances absorption from the small gut. Because of the long half-lives of elimination, repeated consumption of quercetin-containing foods will cause accumulation of quercetin in blood.© 1997 Federation of European Biochemical Societies.Key words: Flavonoid glycoside; Dietary quercetin; Bioavailability; Pharmacokinetics; Human pounds, which are called glycosides in general, or more specifically glucosides, rutinosides, or xylosides depending on their sugar moiety. The sugar-flavonol bond is a (3-glycosidic bond which is resistant to hydrolysis by pancreatic enzymes. It was thought that such glycosides cannot be absorbed [1]. However, when we measured faecal quercetin in ileostomy subjects we found that human absorption of quercetin-p-glucosides from onions was 52%, whereas absorption of quercetin without its sugar moiety, the so-called aglycone, and of quercetin-|3-rutinoside were both only about 20% [12]. These data suggest that the sugar moiety of quercetin glycosides affects their absorption. In the present study we determined the bioavailability and other pharmacokinetic parameters of various quercetin glycosides contained in foods. Subjects ingested onions, apples and pure quercetin rutinoside (rutin), the major quercetin compound found in tea [13]. Onions contain mainly glucose glycosides of quercetin [14,15]. Apples contain a variety of quercetin glycosides, including galactosides, arabinosides, rhamnosides, xylosides, and glucosides ( Fig. 1) [16][17][18]. Preliminary pharmacokinetic data on onions have been published [19].

Technical data for exposure assessment of food enzymes Dietary exposure is part of the overall assessment of food enzymes. In order to develop food process‐based exposure models, a number of different input data are required in tandem with technical conversion factors. This allows for a combination of use levels with food consumption data, which are typically reported as consumed. The use levels are expressed as total organic solids/kg raw materials. For each food process, EFSA identified a list of food groups and collated technical conversion factors. To ensure uniform application of FoodEx food categories and technical conversion factors in the assessment of food enzyme dossiers, stakeholders were consulted via open calls‐for‐data. Feedback was analysed. This document reports the consolidated input parameters for each food process. Regular updates have been made on a yearly basis since 2018, as further process‐specific parameters were generated. The consolidated input data have been used to calculate dietary exposure during the evaluation of food enzyme applications. As well as publishing the input parameters, process‐specific calculators of the food enzyme intake models (FEIM) have also been developed on the basis of summary statistics. These calculators have been deposited at https://zenodo.org/ for open access.

Following a request from the European Commission, EFSA developed an updated scientific guidance to assist applicants in the preparation of applications for food enzymes. This guidance describes the scientific data to be included in applications for the authorisation of food enzymes, as well as for the extension of use for existing authorisations, in accordance with Regulation ( EC ) No 1331/2008 and its implementing rules. Information to be provided in applications relates to source, production and characteristics of the food enzyme, toxicological data, allergenicity and dietary exposure estimation. Source, production and characteristics of the food enzyme are first considered only for enzymes of microbial origin and subsequently for those enzymes derived from plants and for enzymes from animal sources. Finally, the data requested for toxicology, allergenicity and dietary exposure applies to all food enzymes independent of the source. On the basis of the submitted data, EFSA will assess the safety of food enzymes and conclude whether or not they present a risk to human health under the proposed conditions of use.

No abstract

This study presents concentrations of perfluorinated compounds in food and the dietary intake of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in The Netherlands. The concentrations of perfluorinated compounds in food were analyzed in pooled samples of foodstuffs randomly purchased in several Dutch retail store chains with nation-wide coverage. The concentrations analyzed for PFOS and PFOA were used to assess the exposure to these compounds in The Netherlands. As concentrations in drinking water in The Netherlands were missing for these compounds, conservative default concentrations of 7 pg/g for PFOS and 9 pg/g for PFOA, as reported by European Food Safety Authority, were used in the exposure assessment. In food, 6 out of 14 analyzed perfluorinated compounds could be quantified in the majority of the food categories (perfluoroheptanoic acid (PFHpA), PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoro-1-hexanesulfonate (PFHxS), and PFOS). The highest concentration of the sum of these six compounds was found in crustaceans (825 pg/g product, PFOS: 582 pg/g product) and in lean fish (481 pg/g product, PFOS: 308 pg/g product). Lower concentrations were found in beef, fatty fish, flour, butter, eggs, and cheese (concentrations between 20 and 100 pg/g product; PFOS, 29-82 pg/g product) and milk, pork, bakery products, chicken, vegetable, and industrial oils (concentration lower than 10 pg/g product; PFOS not detected). The median long-term intake for PFOS was 0.3 ng/kg bw/day and for PFOA 0.2 ng/kg bw/day. The corresponding high level intakes (99th percentile) were 0.6 and 0.5 ng/kg bw/day, respectively. These intakes were well below the tolerable daily intake values of both compounds (PFOS, 150 ng/kg bw/day; PFOA, 1500 ng/kg bw/day). The intake calculations quantified the contribution of drinking water to the PFOS and PFOA intake in The Netherlands. Important contributors of PFOA intake were vegetables/fruit and flour. Milk, beef, and lean fish were important contributors of PFOS intake.

To date, the use of biomarkers has become generally accepted. Biomarker-driven research has been proposed as a successful method to assess the exposure to xenobiotics by using concentrations of the parent compounds and/or metabolites in biological matrices such as urine or blood. However, the identification and validation of biomarkers of exposure remain a challenge. Recent advances in high-resolution mass spectrometry along with new analytical (postacquisition data-mining) techniques will improve the quality and output of the biomarker identification process. Chronic or even acute exposure to mycotoxins remains a daily fact, and therefore it is crucial that the mycotoxins' metabolism is unravelled so more knowledge on biomarkers in humans and animals is acquired. This review aims to provide the scientific community with a comprehensive overview of reported in vitro and in vivo mycotoxin metabolism studies in relation to biomarkers of exposure for deoxynivalenol, nivalenol, fusarenon-X, T-2 toxin, diacetoxyscirpenol, ochratoxin A, citrinin, fumonisins, zearalenone, aflatoxins, and sterigmatocystin.

Food enzymes are used for technical purposes in the production of food ingredients or foods‐as‐consumed. In the European Union, the safety of a food enzyme is evaluated by EFSA on the basis of a technical dossier provided by an applicant. Dietary exposure is an integral part of the risk assessment of food enzymes. To develop exposure models specific to each food manufacturing process in which food enzymes are used, different input data are required which are then used in tandem with technical conversion factors. This allows the use levels of food enzyme to be related to food consumption data collected in dietary surveys. For each food manufacturing process, EFSA identified a list of food groups (FoodEx1 classification system) and collated technical conversion factors. To ensure a correct and uniform application of these input data in the assessment of food enzyme dossiers, stakeholders were consulted via open calls‐for‐data. In addition to publishing and updating the identified input parameters on an annual basis, single‐process‐specific calculators of the Food Enzyme Intake Models (FEIMs) have been developed. These calculators have been deposited at https://zenodo.org/ since 2018 for open access. By 2023, EFSA had compiled the input data for a total of 40 food manufacturing processes in which food enzymes are employed. In this document, the food manufacturing processes are structured, food groups classified initially in the FoodEx1 system are translated into the FoodEx2 system, and technical factors are adjusted to reflect the more detailed and standardised FoodEx2 nomenclature. The development of an integrated FEIM‐web tool using this collection of input data is carried out for a possible release in 2024. This tool will be able to estimate the exposure to the food enzyme–total organic solids (TOS) when employed in multiple food manufacturing processes.