Dosimetry of human exposure to furan and 2-methylfuran by monitoring urinary biomarkers.

Furan and 2-methylfuran (2-MF) can form during food processing and accumulate in foods at various concentrations depending on processing technology and beverage/meal preparation methods applied prior to consumption. Here, we report a controlled dosimetry study with 20 volunteers (10 male, 10 female) to monitor dietary furan/2-MF exposure. The volunteers followed an eleven-day furan/2-MF-restricted diet in which they consumed freshly prepared coffee brew containing known amounts of furan and 2-MF on two separate occasions (250 mL and 500 mL on days 4 and 8, respectively). Urine was collected over the whole study period and analyzed for key metabolites derived from the primary oxidative furan metabolite cis-2-butene-1,4-dial (BDA) (i.e., Lys-BDA, AcLys-BDA and cyclic GSH-BDA) and the primary 2-MF metabolite acetylacrolein (AcA, 4-oxo-pent-2-enal) (i.e., Lys-AcA and AcLys-AcA). A previously established stable isotope dilution analysis (SIDA) method was utilized. Excretion kinetics revealed two peaks (at 0-2 and 24-36 h) for AcLys-BDA, Lys-BDA, AcLysAcA and LysAcA, whereas GSH-BDA showed a single peak. Notably, women on average excreted the metabolite GSH-BDA slightly faster than men, indicating gender differences. Overall, the study provided further insights into the spectrum of possible biomarkers of furan and 2-methyfuran metabolites occurring in the urine of volunteers after coffee consumption.

Influence of pregnancy and non-fasting conditions on the plasma metabolome in a rat prenatal toxicity study.

The current parameters for determining maternal toxicity (e.g. clinical signs, food consumption, body weight development) lack specificity and may underestimate the extent of effects of test compounds on the dams. Previous reports have highlighted the use of plasma metabolomics for an improved and mechanism-based identification of maternal toxicity. To establish metabolite profiles of healthy pregnancies and evaluate the influence of food consumption as a confounding factor, metabolite profiling of rat plasma was performed by gas- and liquid-chromatography-tandem mass spectrometry techniques. Metabolite changes in response to pregnancy, food consumption prior to blood sampling (non-fasting) as well as the interaction of both conditions were studied. In dams, both conditions, non-fasting and pregnancy, had a marked influence on the plasma metabolome and resulted in distinct individual patterns of changed metabolites. Non-fasting was characterized by increased plasma concentrations of amino acids and diet related compounds and lower levels of ketone bodies. The metabolic profile of pregnant rats was characterized by lower amino acids and glucose levels and higher concentrations of plasma fatty acids, triglycerides and hormones, capturing the normal biochemical changes undergone during pregnancy. The establishment of metabolic profiles of pregnant non-fasted rats serves as a baseline to create metabolic fingerprints for prenatal and maternal toxicity studies.

Fractionation of an anthocyanin-rich bilberry extract and in vitro antioxidative activity testing.

The incidence of chronic diseases increases with advancing age of the population. A commonly discussed cause of chronic diseases is oxidative stress, which occurs in the body when there is an imbalance between the formation and inactivation of so-called reactive oxygen species (ROS). Epidemiological data suggest that a 'healthy diet', with a high content of flavonoids indicates preventive properties and correlates with an inverse effect with respect to the risk of chronic diseases. Berries (especially bilberries, Vaccinium myrtillus L.) are an important source of these flavonoids. In this study, we investigated, in vitro, the antioxidative properties of fractions obtained from a commercially available anthocyanin-rich bilberry extract (BE). As markers for antioxidative activity, the intracellularly generated ROS levels, oxidative DNA damage, and total glutathione (tGSH) levels were determined in the human colon cell lines Caco-2 and HT-29. In Caco-2 cells, the ROS levels and, in both cell lines, the oxidative DNA damage, were significantly reduced in the presence of the original BE and phenolcarbonic acid-rich fraction. Total GSH levels were slightly increased after pretreatment with BE, phenolcarbonic acid and the polymeric fractions, but not with the anthocyanin fraction. In summary, the BE and the therefrom-isolated phenolcarbonic acid-rich fraction, showed the most potent antioxidative activity whereas the polymeric and anthocyanin-rich fraction, in total, were less active.

Consumption of a dark roast coffee decreases the level of spontaneous DNA strand breaks: a randomized controlled trial.

PURPOSE: Coffee consumption has been reported to decrease oxidative damage in peripheral white blood cells (WBC). However, effects on the level of spontaneous DNA strand breaks, a well established marker of health risk, have not been specifically reported yet. We analyzed the impact of consuming a dark roast coffee blend on the level of spontaneous DNA strand breaks. METHODS: Healthy men (n = 84) were randomized to consume daily for 4 weeks either 750 ml of fresh coffee brew or 750 ml of water, subsequent to a run in washout phase of 4 weeks. The study coffee was a blend providing high amounts of both caffeoylquinic acids (10.18 ± 0.33 mg/g) and the roast product N-methylpyridinium (1.10 ± 0.05 mg/g). Before and after the coffee/water consumption phase, spontaneous strand breaks were determined by comet assay. RESULTS: At baseline, both groups exhibited a similar level of spontaneous DNA strand breaks. In the intervention phase, spontaneous DNA strand breaks slightly increased in the control (water only) group whereas they significantly decreased in the coffee group, leading to a 27% difference within both arms (p = 0.0002). Food frequency questionnaires indicated no differences in the overall diet between groups, and mean body weight during the intervention phases remained stable. The consumption of the study coffee substantially lowered the level of spontaneous DNA strand breaks in WBC. CONCLUSION: We conclude that regular coffee consumption contributes to DNA integrity.

Absorption and isomerization of caffeoylquinic acids from different foods using ileostomist volunteers.

BACKGROUND: Polyphenols are thought to play important roles in human nutrition and health but these health effects are dependent on their bioavailability. This study is one of a series with the aim of determining possible effects of food matrices on caffeoylquinic acid (CQA) bioavailability using ileostomy volunteers. METHODS: After a CQA-free diet, ileostomists consumed coffee (746 µmol total CQA), and CQAs in excreted ileal fluid were subsequently identified and quantified with HPLC-diode array detection and HPLC-ESI-MS/MS. In our previous studies, other food sources such as cloudy apple juice (CAJ) (358 µmol CQA) and apple smoothie (AS) (335 µmol CQA) were investigated with the same model. RESULTS: Interesterification of CQA from both apple matrices was observed during gastrointestinal passage, whereas CQA consumed in coffee was not influenced by interesterification reactions. In total, 74.3, 22.4, and 23.8 % of the CQA from CAJ, AS, and coffee, respectively, were absorbed or degraded. CONCLUSION: Our results show that variations in food matrices and variations in phenolic composition have a major influence on intestinal bioavailability and interesterification of the investigated subclass of polyphenols, the CQAs.

Occurrence of 2-ethylhexanoic acid in foods packed in glass jars.

After simultaneous distillation-extraction (SDE) of commercial baby foods (n = 20) and fruit juices (n = 15) (among them 15 and eight products labelled 'organic', respectively) from 11 different suppliers, analyses performed by coupled capillary gas chromatography-mass spectrometry (GC-MS) revealed the presence of 2-ethylhexanoic acid (2-EHA), a known teratogenic compound. 2-EHA was found in 80 and 73% of the baby foods and fruit juices, respectively. Amounts ranged from 0.25 to 3.2 mg kg(-1)(average, 0.55 mg kg(-1)) and from 0.01 to 0.59 mg l(-1) (average, 0.18 mg l(-1)) in baby foods and fruit juices, respectively. GC-MS analysis of the SDE extracts obtained from the plastic gaskets inside the metal lids of the samples under study revealed the gaskets to be the origin of 2-EHA. As shown from the non-contaminated samples under study, obviously technology is available to avoid 2-EHA contamination of glass jar-packed food.

Analysis of heterocyclic aromatic amines in wine by high-performance liquid chromatography-electrospray tandem mass spectrometry.

High-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS-MS) was used for the analysis of heterocyclic aromatic amines (HAAs) in 25 wines from various regions. In 24 wines under study HAAs were detected in the low ng/l range. 2-Amino-3,4-dimethyl-3H-imidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeA alpha C) were found to be the most widely distributed HAAs in the wines under study. There was a difference in the presence of HAAs in white and red wines. In the latter, higher concentrations were found, with MeA alpha C in amount ranging from < 7.5 to 107 ng/l. Compared to the quantities of HAAs evaluated in meat and meat products, the amounts found in wines are 100-1000-fold lower.