Kay L. M. White

Urinary Deoxynivalenol Is Correlated with Cereal Intake in Individuals from the United Kingdom

Background Deoxynivalenol (DON) is a toxic fungal metabolite that frequently contaminates cereal crops. DON is toxic to animals, but the effects on humans are poorly understood, in part because exposure estimates are of limited precision. Objectives In this study we used the U.K. adult National Diet and Nutrition Survey to compare 24-hr urinary DON excretion with cereal intake. Methods One hundred subjects were identified for each of the following cereal consumption groups: low (mean, 107 g cereal/day; range, 88–125), medium (mean, 179 g/day; range, 162–195) and high (mean, 300 g/day; range, 276–325). DON was analyzed in 24-hr urine samples by liquid chromatography–mass spectrometry after purification on immunoaffinity columns. Results DON was detected in 296 of 300 (98.7%) urine samples. Cereal intake was significantly associated with urinary DON (p < 0.0005), with the geometric mean urinary levels being 6.55 μg DON/day [95% confidence interval (CI), 5.71–7.53]; 9.63 μg/day (95% CI, 8.39–11.05); and 13.24 μg/day (95% CI, 11.54–15.19) for low-, medium-, and high-intake groups, respectively. In multivariable analysis, wholemeal bread (p < 0.0005), white bread (p < 0.0005), “other” bread (p < 0.0005), buns/cakes (p = 0.003), high-fiber breakfast cereal (p = 0.016), and pasta (p = 0.017) were significantly associated with urinary DON. Wholemeal bread was associated with the greatest percent increase in urinary DON per unit of consumption, but white bread contributed approximately twice as much as wholemeal bread to the urinary DON levels because it was consumed in higher amounts. Conclusion The majority of adults in the United Kingdom appear to be exposed to DON, and on the basis of the urinary levels, we estimate that some individuals may exceed the European Union (EU) recommended maximum tolerable daily intake of 1,000 ng DON/kg (bw). This exposure biomarker will be a valuable tool for biomonitoring as part of surveillance strategies and in etiologic studies of DON and human disease risk.

Maternal alcohol intake prior to and during pregnancy and risk of adverse birth outcomes: evidence from a British cohort

Background Evidence is conflicting regarding the relationship between low maternal alcohol consumption and birth outcomes. This paper aimed to investigate the association between alcohol intake before and during pregnancy with birth weight and gestational age and to examine the effect of timing of exposure. Methods A prospective cohort in Leeds, UK, of 1303 pregnant women aged 18–45 years. Questionnaires assessed alcohol consumption before pregnancy and for the three trimesters separately. Categories of alcohol consumption were divided into ≤2 units/week and >2 units/week with a non-drinking category as referent. This was related to size at birth and preterm delivery, adjusting for confounders including salivary cotinine as a biomarker of smoking status. Results Nearly two-thirds of women before pregnancy and over half in the first trimester reported alcohol intakes above the Department of Health (UK) guidelines of ≤2 units/week. Associations with birth outcomes were strongest for intakes >2 units/week before pregnancy and in trimesters 1 and 2 compared to non-drinkers. Even women adhering to the guidelines in the first trimester were at significantly higher risk of having babies with lower birth weight, lower birth centile and preterm birth compared to non-drinkers, after adjusting for confounders (p<0.05). Conclusions We found the first trimester to be the period most sensitive to the effect of alcohol on the developing fetus. Women adhering to guidelines in this period were still at increased risk of adverse birth outcomes. Our findings suggest that women should be advised to abstain from alcohol when planning to conceive and throughout pregnancy.

Association between Tortilla Consumption and Human Urinary Fumonisin B1 Levels in a Mexican Population

Fumonisins are mycotoxins produced by Fusarium spp. and commonly contaminate maize and maize products worldwide. Fumonisins are rodent carcinogens and have been associated with human esophageal cancer. However, the lack of a valid exposure biomarker has hindered both the assessment of human exposure and the evaluation of disease risk. A sensitive liquid chromatography-mass spectrometry method to measure urinary fumonisin B1 (FB1) following extraction on Oasis MAX cartridges was established and applied to urine samples from women in a cohort recruited in Morelos County, Mexico. Urinary FB1 was compared with dietary information on tortilla consumption. FB1 recovery in spiked samples averaged 94% as judged by deuterium-labeled FB1 internal standard. Urinary FB1 was determined in 75 samples from women selected based on low, medium, or high consumption of maize-based tortillas. The geometric mean (95% confidence interval) of urinary FB1 was 35.0 (18.8-65.2), 63.1 (36.8-108.2), and 147.4 (87.6-248.0) pg/mL and the frequency of samples above the detection limit (set at 20 pg FB1/mL urine) was 45%, 80%, and 96% for the low, medium, and high groups, respectively. Women with high intake had a 3-fold higher average FB1 levels compared with the “low intake” group (F = 7.3; P = 0.0015). Urinary FB1 was correlated with maize intake (Ptrend = 0.001); the correlation remained significant after adjusting for age, education, and place of residence. This study suggests that measurement of urinary FB1 is sufficiently sensitive for fumonisin exposure assessment in human populations and could be a valuable tool in investigating the associated health effects of exposure. (Cancer Epidemiol Biomarkers Prev 2008;17(3):688–94)

A comparison of deoxynivalenol intake and urinary deoxynivalenol in UK adults.

The relationship between deoxynivalenol (DON) intake and first morning urinary DON was examined in UK adults to validate the latter as a biomarker of human exposure. DON was assessed in first morning samples collected during a period of normal diet, a wheat-restriction intervention diet, and partial wheat-restriction intervention in which bread was allowed. During the partial intervention duplicate bread portions were collected for DON analysis. During the normal diet, partial intervention and full intervention, urinary DON was detected in 198/210 (geometric mean 10.1 ng DON mg−1 creatinine, 95% confidence interval (CI) 8.6–11.6 ng mg−1; range nd–70.7 ng mg−1), in 94/98 (5.9 ng mg−1, 95% CI 4.8–7.0 ng mg−1; range nd–28.4 ng mg−1), and 17/40 (0.5 ng mg−1, 95% CI 0.3–0.7 ng mg−1; range nd–3.3 ng mg−1) volunteers, respectively. A strong correlation between DON intake and the urinary biomarker was observed (p <0.001, adjusted r2 = 0.83) in models adjusting for age, sex and body mass index. These data demonstrate a quantitative correlation between DON exposure and urinary DON, and serve to validate the use of urinary DON as an exposure biomarker.

Dietary wheat reduction decreases the level of urinary deoxynivalenol in UK adults

In animals deoxynivalenol (DON) causes vomiting, feed refusal, growth retardation, and affects the immune system. DON is a common contaminant of wheat, however, validated biomarker data to assess exposure at the individual level and therefore any associated health effects are lacking. The development of a highly robust assay for urinary DON involving immunoaffinity (IAC) clean-up and liquid chromatography (LC)-mass spectrometric (MS) detection has allowed the assessment of (1) DON exposure within UK individuals and (2) a wheat intake intervention on urinary DON levels. Twenty-five volunteers from the United Kingdom (aged 21–59 years) completed semi-weighed food diaries on days 1 and 2 (normal diet), and a morning urine sample was provided on day 3. On days 3–6 (intervention), individuals restricted major sources of wheat intake following dietary guidance. Diaries were completed on days 5 and 6, and a further morning urine was provided on day 7. Urinary DON was measured following IAC clean-up and analysis by LC–MS. Wheat-based food intake (mean 322 g/day, range: 131–542 g/day), was significantly (P<0.001) reduced during the intervention to 26 g/day (range: 0–159 g/day) indicating good compliance. DON was detected in all 25 urine samples taken on day 3 (geometric mean 7.2 ng DON/mg creatinine (95% confidence interval (CI) 4.9–10.5 ng/mg), but following the intervention there was a significant 11-fold reduction (P<0.001) to 0.6 ng per mg (95% CI 0.4–0.9 ng/mg). These data are unique in demonstrating human exposure to DON in the United Kingdom using a urinary biomarker. Furthermore, the study demonstrates that exposure can be markedly reduced by avoiding wheat in the diet. On the basis of urinary biomarker levels some individuals are predicted to exceed current recommended daily intakes of DON, and thus the health consequences of these exposures merit further investigation.

Assessment of deoxynivalenol metabolite profiles in UK adults

Deoxynivalenol (DON) requires no activation for toxicity, though susceptibility may reflect individual variations in detoxification. This study reports the measurement of un-metabolised urinary DON (free DON) and DOM-1 in samples previously analysed for the combined measure of free DON+DON-glucuronide (fD+DG), with a concentration >5 ng/ml, for 34 UK adults. Four consecutive daily urine samples were analysed from twenty-two individuals, whilst from 12 individuals only a single sample was analysed. The mean (median) concentration of urinary fD+DG in this sub-set was 17.8 ng/ml (13.8 ng/ml), range 5.0-78.2 ng/ml. In 23/34 (68%) individuals, free DON was detected, mean 2.4 ng/ml; range 0.5-9.3 ng/ml. Urinary DOM-1 was detected in 1/34 (3%) of individuals; present at ∼1% of urinary fD+DG concentration for that individual. The concentration of fD+DG combined was significantly correlated with urinary free DON (p<0.001, R(2)=0.65), but not with the percentage of free DON to fD+DG (p=0.615, R(2)=0.01), suggesting that the level of DON exposure did not affect the metabolism to DG within the range observed. In this survey most individuals had no detectable urinary DOM-1 and 68% did not detoxify all of the ingested DON to DON-glucuronide. This study needs to be extended to understand whether the fD / DG ratio provides a phenotypic measure of DON susceptibility.

Deoxynivalenol: rationale for development and application of a urinary biomarker.

Mycotoxins are common dietary contaminants in most regions of the world. The frequency of exposure to the various families of mycotoxins is often dependent on geographic location, national wealth and related agricultural and regulatory infrastructure, combined with diversity of diet and degree of food sufficiency. Deoxynivalenol (DON) is a Fusarium mycotoxin that frequently contaminates wheat, corn and barley in temperate regions. A number of acute poisoning incidences have been linked to DON-contaminated foods and chronic exposure to lower levels of DON has been predicted in many regions. DON is a potent animal toxin and exposure in humans may cause gastroenteritis, growth faltering and immune toxicity. An ability to conduct accurate exposure assessment at the individual level is required to fully understand the potential health consequences for humans. To date, such exposure biomarkers have been lacking for many important mycotoxins, including DON. To better assess exposure to DON at the individual level, we have developed a robust urinary assay, incorporating immunoaffinity column (IAC) enrichment and LC–MS detection. Further refinement of this urinary assay, by inclusion of 13C-DON as an internal standard, was then undertaken and tested within the UK. DON was frequently observed in urine and was significantly associated with cereal intake. A dietary intervention study demonstrated that avoiding wheat in the diet markedly reduced urinary levels of DON. This biomarker requires further validation but our initial data suggest it may provide a useful tool in epidemiological investigations of the potential health consequences of this common environmental toxin.

Plasma and Esophageal Mucosal Levels of Vitamin C: Role in the Pathogenesis and Neoplastic Progression of Barrett's Esophagus

Antioxidants may protect against the development of esophageal adenocarcinoma. Blood samplesand endoscopic biopsies (squamous, Barretts, and gastric mucosa) were obtained from 48 Barrettsesophagus (BE) patients, while 48 age- and sex-matched controls provided blood samples only.Plasma concentrations of vitamins A, C, and E were measured in all subjects, while vitamin C wasmeasured in relation to the type of mucosa. Plasma total vitamin C level, but not vitamin A or E,was lower in BE patients compared to controls ( P = 0.014). Tissue levels of total vitamin C weresignificantly lower in Barretts compared with squamous mucosa ( P = 0.047). Apositive associationwas observed between plasma vitamin C and dietary intake of vitamin C, while there was an inverseassociation with alcohol consumption. The lower levels of vitamin C in plasma of BE patients andin Barretts mucosa compared with squamous mucosa are consistent with oxidative stress being ofimportance in the pathogenesis and neoplastic progression of BE.

Assessing caffeine exposure in pregnant women

Studies on the effects of caffeine on health, while numerous, have produced inconsistent results. One of the most uncertain and controversial effects is on pregnancy outcome. Studies have produced conflicting results due to a number of methodological variations. The major challenge is the accurate assessment of caffeine intake. The aim of the present study was to explore different methods of assessing caffeine exposure in pregnant women. Twenty-four healthy pregnant women from the UK city of Leeds completed both a detailed questionnaire, the caffeine assessment tool (CAT) designed specifically to assess caffeine intake and a prospective 3 d food and drink diary. The women also provided nine saliva samples over two consecutive days for estimation of caffeine and a metabolite (paraxanthine). Caffeine intakes from the CAT and diary showed adequate agreement (intra-class correlation coefficient of 0.5). For saliva caffeine and paraxanthine measures, the between-sample variation (within the same woman) was greater than between-woman and between-day variation. However, there was still adequate agreement between these measures and the CAT. The CAT is a valuable tool that is now being used in a large prospective study investigating caffeines role in pregnancy outcome.

A comparison of 24 h urinary deoxynivalenol with recent v. average cereal consumption for UK adults.

Deoxynivalenol (DON) is a toxic fungal metabolite found on wheat, maize and barley. We previously reported a significant association between the amount of DON in a single 24 h urine sample and the average cereal intake over 7 d for 300 UK adults. In this more detailed analysis of the data, food diary information (n 255) for the day of urine collection (model I), the previous 24 h period (model II) and the day of urine collection plus the previous 24 h combined (model III) were further examined to assess whether the recent intake of cereal correlated more strongly with urinary DON, compared with the longer-term assessment of usual cereal intake from 7 d food diaries (model IV). DON was detected in 254/255 (99.6 %) urine samples (mean 12.0 microg/d; range not detected-66 microg/d). For all the models, total cereal intake was positively associated with urinary DON (P < 0.001) in each model. The goodness of fit (adjusted R2 value) was used to assess how well each model explained the variation in urinary DON. Model I provided a better goodness of fit (adjusted R2 0.22) than model IV (adjusted R2 0.19), whereas model III provided the best fit (adjusted R2 0.27). These data suggest that the inter-individual variation in urinary DON was somewhat better explained by recent cereal intake compared with usual cereal intake assessed over 7 d.