124 research outputs found
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Nutrition epidemiology of flavan-3-ols: the known unknowns
Nutritional epidemiology has an important role, as it can provide long-term data from large populations and does not rely on surrogate markers for morbidity/mortality. Meaningful interpretation and applications of outcomes from epidemiological studies depend on the accurate assessment of dietary intake, which is currently mainly based on a combination of self-reporting and food composition data. Flavan-3-ols are a group of bioactives (non-essential dietary components with significant impact on health) that is a possible candidate for the development of dietary recommendations. The breadth of data available on their effect on health also provides the basis for investigating the suitability of the methods currently used in nutritional epidemiology to assess the health effects of bioactives. The outcomes of this assessment demonstrate that the limitations of currently used methods make it virtually impossible to estimate intake accurately from self-reported dietary data. This is due to the limitations of self-reporting, especially from food-frequency questionnaires, and the inability of currently used methods to deal with the high variability of food composition. Indeed, the estimated intake of flavan-3-ols, can only be interpreted as a marker of specific dietary patterns, but not as the actual intake amount. The interpretation of results from such studies are fraught with serious limitations, especially for establishing associations between intake and health and the development of dietary recommendations. Alternative assessment not affected by these limitations, such as biomarkers, are required to overcome these limitations. The development of nutritional biomarkers is therefore crucial to investigate the health effect of bioactives
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Vegetable oil as fat replacer inhibits formation of heterocyclic amines and 2 polycyclic aromatic hydrocarbons in reduced fat pork patties
Formation of heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons 9 (PAHs) was examined to evaluate the impact of using vegetable oil as fat 10 replacement on carcinogen formation in meat product. Pork patties were formulated 11 with 40% fat replacement by olive oil, sunflower oil or grape seed oil, respectively 12 and cooked at 180oC or 220oC. Control patties contained the highest amount of 13 HCAs compared with all other patties at both temperatures. Olive oil and sunflower 14 oil replacement completely inhibited formation of MeIQ (2-amino-3, 4-15 methylimidazo[4,5-f]quinoline), while grape seed oil completely inhibited MeIQx (2-
16 amino-3,8-dimethylimidazo[4,5-f]quinoxaline), 4,8-DiMeIQx (2-amino-3,4,8-
17 trimethylimidazo[4,5-f]quinoxaline) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-
18 b]pyridine) in patties. Grape seed oil achieved the highest inhibition capacity
19 compared with sunflower oil and olive oil. HCAs increased significantly with cooking
20 temperature (p<0.05), but no difference was observed in total PAHs for patties
21 cooked at different temperature (p>0.05). In conclusion, fat replacement with
22 sunflower oil, olive oil or grape seed oil in pork patties could reduce the formation of
23 HCAs without compromising eating quality
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Sugar intake among German adolescents: trends from 1990-2016 based on biomarker excretion in 24-h urine samples
Trend analyses based on dietary records suggest decreases in the intakes of total (TS), added (AS) and free sugar (FS) since 2005 among children and adolescents in Germany. In terms of age trends, TS intake decreased with increasing age. However, self-reported sugar intake in epidemiological studies is criticized, as it may be prone to bias due to selective underreporting. Furthermore, adolescents are more susceptible to underreporting than children. We thus analyzed time and age trends in urinary fructose excretion (FE), sucrose excretion (SE) and the sum of both (FE+SE) as biomarkers for sugar intake among 8.5-16.5-year-old adolescents. Urinary sugar excretion was measured by UPLC-MS/MS in 997 24-h urine samples collected from 239 boys and 253 girls participating in the DONALD study cohort between 1990 and 2016. Time and age trends of log-transformed FE, SE and FE+SE were analyzed using polynomial mixed-effects regression models. Between 1990 and 2016 FE as well as FE+SE decreased (linear time trend: p=0.0272 and p<0.0001, respectively). A minor increase in excretion during adolescence was confined to FE (linear age trend: p=0.0017). The present 24-h excretion measurements support a previously reported dietary-record based decline in sugar intake since 2005. However, the previous seen dietary record-based decrease in TS from childhood to late adolescence was not confirmed by our biomarker analysis, suggesting a constant sugar intake for the period of adolescence
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Phytoestrogen consumption and association with breast, prostate and colorectal cancer in EPIC Norfolk
Phytoestrogens are polyphenolic secondary plant metabolites that have structural and functional similarities to 17β-oestradiol and have been associated with a protective effect against hormone-related cancers. Most foods in the UK only contain small amounts of phytoestrogens (median content 21 μg/100 g) and the highest content is found in soya and soya-containing foods. The highest phytoestrogen content in commonly consumed foods is found in breads (average content 450 μg/100 g), the main source of isoflavones in the UK diet. The phytoestrogen consumption in cases and controls was considerably lower than in Asian countries. No significant associations between phytoestrogen intake and breast cancer risk in a nested case-control study in EPIC Norfolk were found. Conversely, colorectal cancer risk was inversely associated with enterolignan intake in women but not in men. Prostate cancer risk was positively associated with enterolignan intake, however this association became non-significant when adjusting for dairy intake, suggesting that enterolignans can act as a surrogate marker for dairy or calcium intake
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Assays for the identification and quantification of sialic acids: challenges, opportunities and future perspectives
N-Acetyl neuraminic acid (sialic acid) is a monosaccharide generally found as the terminating unit on glycans, which in turn are found on the surface of cells and glycoproteins. These glycans aid in a variety of biological functions such as cell interactions and immune response. Sialic acid has been identified as a biomarker for cardiovascular disease, diabetes and a range of other inflammatory and degenerative conditions. It has also been identified as a marker for different types of cancer. Sialic acid levels vary depending on the level of inflammation present during the course of an inflammatory disease and it is overexpressed by tumours as a shield against the immune system. Since the discovery of sialic acid, numerous assays have been developed for the identification and quantification of different sialic acid derivative monosaccharides and these assays fall into four main groups: colorimetric, fluorometric, enzymatic and chromatographic/mass spectrometric, with much overlap between these. Given the importance of sialic acids in biological pathways, this review article critically appraises assays that are used to detect and quantify sialic acid and its derivatives. Thus it details the method, sensitivity, specificity and wider scope of a range of assays, and concludes by suggesting some future directions for assay development and application. In this way, insight is provided into assays that allow for the accurate quantitation of sialic acid in biological samples, which may facilitate identification of the roles of sialic acid in healthy and disease pathways
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The mediating role of obesity on the prospective association between urinary sucrose and diabetes incidence in a sub-cohort of the EPIC-Norfolk
Background/objectives
Findings from epidemiological studies showed controversial findings between dietary sugar intake and the development of diabetes. Most of these studies assessed dietary sugar intake by self-reports which might be prone to bias. Urinary sucrose, an objective biomarker of sucrose intake, might provide better insights into this association. Thus, the aim of this study was to investigate the associations between sucrose intake, measured via self-reports and urinary sucrose, with incident diabetes and to detect the impact of obesity on this association.
Subjects/methods
Data of a sub-group (n = 2996) from the prospective EPIC-Norfolk cohort were investigated. Sucrose intake was assessed by self-reports (validated food frequency questionnaire (FFQ) and 7-day diet diaries (7DD)) and as an objective urinary sucrose biomarker. Cox proportional hazard models were conducted to calculate hazard ratios (HRs) and 95% confidence intervals (CI) for the associations between urinary and dietary sucrose intake and incident diabetes. Mediation analysis was performed to investigate the mediated percentage of body mass index (BMI) and waist circumference (WC) on this association.
Results
The mean age of the participants was 60.6 ± 9.5 years and 53% were women. After a mean follow-up of 11.2 ± 2.9 years, 97 participants developed diabetes. Findings suggested inverse associations regarding incident diabetes for self-reported sucrose intake per 50 g/d via 7DD [HR: 0.63 (95% CI: 0.43, 0.91)], and a tendency via FFQ [HR: 0.81 (95% CI: 0.46, 1.42)]. Urinary sucrose indicated a positive association with incident diabetes for each increase of 100 µM [HR: 1.14 (95% CI: 0.95, 1.36)]. The proportion mediated of BMI and WC for this association was 16 and 22%.
Conclusions
These findings indicate that sucrose measured as objective urinary biomarker points to a positive association with incident diabetes. BMI might partly mediate this association. However, to obtain more precise results, more studies are warranted that consider this objective biomarker
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Estimated intake of dietary phyto-oestrogens in Australian women and evaluation of correlates of phyto-oestrogen intake.
The role of dietary phyto-oestrogens in health has been of continued interest and debate, but data available on the distribution of intake in the Australian diet are scarce. Therefore, we aimed to estimate phyto-oestrogen consumption in Australian women, describe the pattern of intake and identify correlates of high phyto-oestrogen intake. Study participants were 2078 control women (18-79 years) from two population-based case-control studies on gynaecological cancers (2002-2007). Dietary information was obtained using a 135-item FFQ, and the intakes of isoflavones, lignans, enterolignans and coumestans, including their individual components, were estimated using a database of phyto-oestrogen content in food developed in the UK. Median total intake (energy-adjusted) of phyto-oestrogens was 1·29 mg/d, including 611 µg/d isoflavones, 639 µg/d lignans, 21 µg/d enterolignans and 8 µg/d coumestrol. Both isoflavone and lignan intakes were strongly skewed towards higher values and positively correlated with age. Women consumed on average two servings of soyabean foods/week. Compared to lower phyto-oestrogen consumers (≤1·29 mg/d, median split), higher phyto-oestrogen consumers (>1·29 mg/d) were slightly older, less likely to be smokers, had a higher educational and physical activity level, lower BMI, lower intake of dietary fat, and higher intake of fibre, selected micronutrients and soyabean foods (all P < 0·03). The daily intake of phyto-oestrogens in Australian women with predominantly Caucasian ethnicity is approximately 1 mg; this is similar to other Western populations, but considerably lower than that among Asian women. However, those with a relatively high phyto-oestrogen diet seem to have a healthier lifestyle and a more favourable dietary profile compared to others
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Structurally-related (−)-epicatechin metabolites in humans: assessment using de novo chemically synthesized authentic standards
Accumulating data suggest that diets rich in flavanols and procyanidins are beneficial for human health. In this context, there has been a great interest in elucidating the systemic levels and metabolic profiles at which these compounds occur in humans. While recent progress has been made, there still exist considerable differences and various disagreements with regard to the mammalian metabolites of these compounds, which in turn is largely a consequence of the lack of availability of authentic standards that would allow for the directed development and validation of expedient analytical methodologies. In the present study, we developed a method for the analysis of structurally-related flavanol metabolites using a wide range of authentic standards. Applying this method in the context of a human dietary intervention study using comprehensively characterized and standardized flavanol- and procyanidin-containing cocoa, we were able to identify the structurally-related (−)-epicatechin metabolites (SREM) postprandially extant in the systemic circulation of humans. Our results demonstrate that (−)-epicatechin-3′-β-D-glucuronide, (−)-epicatechin-3′-sulfate, and a 3′-O-methyl(−)-epicatechin-5/7-sulfate are the predominant SREM in humans, and further confirm the relevance of the stereochemical configuration in the context of flavanol metabolism. In addition, we also identified plausible causes for the previously reported discrepancies regarding flavanol metabolism, consisting to a significant extent of inter-laboratory differences in sample preparation (enzymatic treatment and sample conditioning for HPLC analysis) and detection systems. Thus, these findings may also aid in the establishment of consensus on this topic
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