Effect of Red Orange Juice Consumption on Body Composition and Nutritional Status in Overweight/Obese Female: A Pilot Study.

The main objective of this research was to determine whether a commercial orange juice rich in anthocyanins could have an effect on body weight and on clinical parameters related to obesity including antioxidant status, lipid profile, and metabolic and inflammatory biomarkers. 11 women with an average BMI of 34.4 ± 4.8 kg/m2 were enrolled in a pilot study. Over a period of 12 weeks they received 500 mL daily dose into two doses (250 mL) of commercial red orange juice (COJ). The biochemical parameters were measured at baseline and at the end of the study (12 weeks). One month later upon free diet, a follow-up was performed measuring the same variables. The daily consumption of 500 mL of COJ had no significant effects on body weight, while there was a decrease in total cholesterol and LDL cholesterol. The grade of obesity implies different changes in inflammation biomarkers. In obese women, our data do not seem to support evidence that commercial red orange juice consumption acts as functional food preventing obesity and metabolic disorders such as insulin resistance and/or inflammatory status.

Effects of consumption of whole grain foods rich in lignans in healthy postmenopausal women with moderate serum cholesterol: a pilot study.

This study aims at investigating the effect of an experimental period of intake of whole grain foods rich in lignans as part of an habitual diet on the plasma and urinary excretion of enterolignans, the biomarkers of lipid metabolism and the immunological and antioxidant status in a group of postmenopausal women with moderate serum cholesterol. A randomized double-blind crossover study was completed on 13 subjects in 12-weeks after protocol approval of an ethical committee. The subjects consumed whole grain foods high in lignans (30 g/d of breakfast cereals or biscuits, etc., 80 g/d of whole grain pasta) or refined grain foods for 4 weeks, separated by a 2-weeks wash-out period. A modest hypocholesterolemic effect (p < 0.05) of the whole grain diet was observed and the intake of whole grain products rich in lignans was also associated with an increase in urinary enterodiol excretion (p < 0.05).

Lifestyle habits and mortality from all and specific causes of death: 40-year follow-up in the Italian Rural Areas of the Seven Countries Study.

OBJECTIVES: Three lifestyle factors were investigated in a population study to explore their relationships with a long-term mortality. MATERIAL AND METHODS: In a cohort of 1564 men aged 45-64 and examined in 1965 within the Italian Rural Areas of the Seven Countries Study, smoking habits, physical activity at work and eating habits (as derived from factor analysis) were determined. During the follow-up 693 men died in 20 years and 1441 in 40 years. RESULTS: In Cox proportional hazards models men smoking cigarettes (versus never smokers), those having a sedentary activity (versus the very active) and those following the Diet Score 1, indexing an unhealthy Diet (versus men with a Diet close to the healthy Mediterranean style) had highly significant hazards ratios (HR) in relations with 20- and 40-year mortality from all causes, coronary heart disease (CHD), cardiovascular disease (CVD) and cancer. HR for all causes in 40 years were 1.44 (95% confidence intervals, CI, 1.27 and 1.64) for smokers, 1.43 (CI 1.23 and 1.67) for sedentary people, and 1.31 (CI 1.15 and 1.50) for men with unhealthy diet. Larger HR were found for CHD, CVD and cancers deaths. Combination of 3 unhealthy risk factors versus their absence was associated with 4.8-year life loss in the 20-year follow-up and 10.7-year in the 40-year follow-up. CONCLUSIONS: Lifestyle behavior linked to physical activity and smoking and eating habits is strongly associated with mortality and survival in middle aged men during long-term follow-up.

Antioxidant effect of zinc supplementation on both plasma and cellular red-ox status markers in a group of elderly Italian population.

OBJECTIVES: The aim of this work was to evaluate the effect of long term supplementation with two moderate dose of Zn on plasma and cellular red-ox status markers in elderly volunteers. DESIGN, SETTING AND SUBJECTS: In a double blind study 108 healthy volunteers, aged 70-85 years, were enrolled. They were randomly divided in 3 groups of treatment, receiving placebo, 15 mg/day and 30 mg/day of Zn for 6 months. Red-ox status markers were assessed at baseline and after 6 months evaluating carotenoids, vitamin A and E in plasma; glutathione (GSH), thiol groups (RSH), malondialdehyde (MDA), percentage of haemolysis and methemoglobin in erythrocytes. RESULTS: Zn supplementation had no significant effects on red-ox status markers except for vitamin A levels (from 1.94±0.44 to 2.18±0.48 µM in volunteers receiving 15 mg of Zn and from 1.95±0.46 to 2.26±0.56 µM in volunteers receiving 30 mg of Zn), which increased proportionally to zinc dose. CONCLUSIONS: It appears that, differently from unhealthy populations, long-term supplementation with two moderate doses of Zn in a healthy elderly population, with an adequate Zn nutritive status and macro and micronutrients intakes in the range of normality, is an inefficient way to increase antioxidant defences.

Measuring the food and built environments in urban centres: reliability and validity of the EURO-PREVOB Community Questionnaire.

OBJECTIVES: The authors designed an instrument to measure objectively aspects of the built and food environments in urban areas, the EURO-PREVOB Community Questionnaire, within the EU-funded project 'Tackling the social and economic determinants of nutrition and physical activity for the prevention of obesity across Europe' (EURO-PREVOB). This paper describes its development, reliability, validity, feasibility and relevance to public health and obesity research. STUDY DESIGN: The Community Questionnaire is designed to measure key aspects of the food and built environments in urban areas of varying levels of affluence or deprivation, within different countries. The questionnaire assesses (1) the food environment and (2) the built environment. METHODS: Pilot tests of the EURO-PREVOB Community Questionnaire were conducted in five to 10 purposively sampled urban areas of different socio-economic status in each of Ankara, Brno, Marseille, Riga, and Sarajevo. Inter-rater reliability was compared between two pairs of fieldworkers in each city centre using three methods: inter-observer agreement (IOA), kappa statistics, and intraclass correlation coefficients (ICCs). RESULTS: Data were collected successfully in all five cities. Overall reliability of the EURO-PREVOB Community Questionnaire was excellent (inter-observer agreement (IOA) > 0.87; intraclass correlation coefficients (ICC)s > 0.91 and kappa statistics > 0.7. However, assessment of certain aspects of the quality of the built environment yielded slightly lower IOA coefficients than the quantitative aspects. CONCLUSIONS: The EURO-PREVOB Community Questionnaire was found to be a reliable and practical observational tool for measuring differences in community-level data on environmental factors that can impact on dietary intake and physical activity. The next step is to evaluate its predictive power by collecting behavioural and anthropometric data relevant to obesity and its determinants.

Monitoring antioxidant defenses and free radical production in space-flight, aviation and railway engine operators, for the prevention and treatment of oxidative stress, immunological impairment, and pre-mature cell aging.

Degenerative diseases, immune impairment, and premature ageing commonly affect professional categories exposed to severe environmental and psychological stress. Among these, cosmonauts routinely experience extreme conditions due to microgravity, space radiation, altered oxygen supply, physical and mental fatigue during training, spaceflight, and post-flight. Long route aviation pilots display elevated oncogenic risk, connected with cosmic radiation overexposure, and high mortality rates for cardiovascular causes. Engine drivers, like pilots, are affected by health consequences of psycho-emotional stress, and burnout syndrome. The free radical (FR)/antioxidant (AO) imbalance is a common feature in all these pathological conditions. To assess the effective relevance of oxidative stress, we analyzed blood and urine reliable markers of FR production and AO defenses in 12 Russian cosmonauts, 55 airline pilots, 63 train engine drivers, and 50 age-matched controls by measuring the following: (a) lipophilic/hydrophilic low-molecular weight AO and AO enzyme activities, (b) nitric oxide, superoxide anion, hydroperoxide production, and (c) urinary catecholamine/serotonine metabolites and lipoperoxidation markers. Cosmonauts showed elevated granulocyte superoxide and nitric oxide production, increased erythrocyte superoxide dismutase activity and glutathione oxidation, and drastically decreased plasma/leucocyte lipophilic AO levels (P < 0.001-0.01). Aviation pilots, like train drivers, displayed a mild but constant oxidative stress, more pronounced in intercontinental routes pilots, and consistent with lymphocyte chromosomal alterations, DNA oxidation, and cardiovascular malfunction. Results obtained on these selected professionals operating under wearing conditions offer a solid molecular basis for advising the regular monitoring of clinical biochemistry laboratory markers of AO/FR status, to tailor individually specific AO supplementation and diet regimen, and monitor treatment outcomes.

Sampling and processing of fresh blood samples within a European multicenter nutritional study: evaluation of biomarker stability during transport and storage.

INTRODUCTION: Analysis of several biological markers improves the quality and physiologic comprehension of data obtained in epidemiological nutritional studies. AIM: To develop a methodology that guarantees the centralized analysis and quality assurance of the most relevant blood parameters from fresh blood samples in adolescents in a European multicenter study. MATERIALS AND METHODS: Stability of selected nutrients and biomarkers (vitamins, fatty acids, iron metabolism and immunological parameters) chosen with respect to time and temperature of sample transport and storage was evaluated as part of the pilot study of the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) project. RESULTS: Routine biochemistry and iron status parameters included in the HELENA Cross-Sectional Study (CSS) protocol could be analyzed within 24 h from fresh blood samples without any stability problems (coefficient of variation (CV)<5%, P<0.05). However, stability tests for lymphocyte subpopulations, vitamin C and fatty acids showed that they are very unstable at room temperature without any treatment. Therefore, a special handling for these samples was developed. Vitamin C was stabilized with metaphosphoric acid and transported under cooled conditions (CV 4.4%, recovery rate >93%, P>0.05). According to the results, a specific methodology and transport system were developed to collect blood samples at schools in 10 European cities and to send them to the centralized laboratory (IEL, Bonn, Germany). To guarantee good clinical practice, the field workers were instructed in a training workshop and a manual of operation was developed. CONCLUSION: The handling and transport system for fresh blood samples developed for the European multicenter study HELENA is adequate for the final part of the HELENA-CSS and will provide, for the first time, reference values for several biological markers in European adolescents.

Effect of zinc supplementation on vitamin status of middle-aged and older European adults: the ZENITH study.

OBJECTIVE: To assess the effects of zinc supplementation on vitamin status in middle-aged and older volunteers. SUBJECTS/METHODS: Three hundred and eighty-seven healthy middle-aged (55-70 years) and older (70-85 years) men and women, randomly allocated to three groups to receive 15 or 30 mg Zn/day or placebo for 6 months. Dietary intake was assessed by means of a validated 4-day recall record. Fasting blood samples were simultaneously analysed for levels of plasma retinol and alpha-tocopherol by high-performance liquid chromatography. Erythrocyte folates were measured by a competitive immunoassay with direct chemiluminescence detection on an automatized immunoanalyser. Biochemical measurements were performed at baseline and after 3 and 6 months of zinc supplementation. RESULTS: Plasma vitamin A levels were significantly increased proportionally with zinc dose and period of treatment, particularly at 6 months (for 15 mg Zn/day, P<0.05; for 30 mg Zn/day, P<0.0001); no significant changes were observed in the placebo group. There was no effect of zinc supplementation on vitamin E/cholesterol ratio and erythrocyte folates. CONCLUSIONS: Our results show that a long-term zinc supplementation increases plasma vitamin A levels in middle-aged and older people of similar characteristics to those involved in this study. Moreover, supplementation influences serum zinc levels but does not affect erythrocyte zinc concentration and both plasma vitamin E and erythrocyte folate status.

Absorption and metabolism of bioactive molecules after oral consumption of cooked edible heads of Cynara scolymus L. (cultivar Violetto di Provenza) in human subjects: a pilot study.

The current growing interest for natural antioxidants has led to a renewed scientific attention for artichoke, due not only to its nutritional value, but, overall, to its polyphenolic content, showing strong antioxidant properties. The major constituents of artichoke extracts are hydroxycinnamic acids such as chlorogenic acid, dicaffeoylquinic acids caffeic acid and ferulic acid, and flavonoids such as luteolin and apigenin glycosides. In vitro studies, using cultured rat hepatocytes, have shown its hepatoprotective functions and in vivo studies have shown the inhibition of cholesterol biosynthesis in human subjects. Several studies have shown the effect on animal models of artichoke extracts, while information on human bioavailability and metabolism of hydroxycinnamates derivatives is still lacking. Results showed a plasma maximum concentration of 6.4 (SD 1.8) ng/ml for chlorogenic acid after 1 h and its disappearance within 2 h (P< 0.05). Peak plasma concentrations of 19.5 (SD 6.9) ng/ml for total caffeic acid were reached within 1 h, while ferulic acid plasma concentrations showed a biphasic profile with 6.4 (SD1.5) ng/ml and 8.4 (SD4.6) ng/ml within 1 h and after 8 h respectively. We observed a significant increase of dihydrocaffeic acid and dihydroferulic acid total levels after 8 h (P<0.05). No circulating plasma levels of luteolin and apigenin were present. Our study confirms the bioavailability of metabolites of hydroxycinnamic acids after ingestion of cooked edible Cynara scolymus L. (cultivar Violetto di Provenza).

Descriptive data on lifestyle, anthropometric status and mental health in italian elderly people.

OBJECTIVE: The objective of this paper is to provide descriptive information on anthropometric status, pathological conditions, cognitive impairment and lifestyle in apparently healthy elderly Italian people. DESIGN, SETTING AND SUBJECTS: In order to recruit the volunteers for the ZENITH study, 359 Italian participants (167 men and 192 women), aged between 70 and 85 years, free living in Rome, were selected. Volunteers underwent a full clinical examination, anthropometric measurements (height, weight), a lifestyle questionnaire and mental health assessment (cognitive impairment and depression). RESULTS: The prevalence of overweight and obesity was high (57% and 22% in men; 43% and 27% in women). Obesity was associated with low socio-economic profile in about 40% of participants. Although the sample was selected by family doctors and was apparently healthy, after medical screening the presence of several pathologies, particularly diabetes in 21% of participants was observed. There was a low prevalence of cognitive impairment in 4% of men and 7% of women and possible depression in 9% of men and 19% of women. The lifestyle questionnaire showed that most of their time was spent in light activities such as reading, watching TV or playing cards and significant differences between sex and BMI categories were observed (P=0.000). CONCLUSION: The results confirm the increasingly sedentary lifestyle of modern populations and demonstrate the need for sensitive and individualised strategies to design appropriate health promotion and disease prevention programs for older adults.

Importance of zinc in the elderly: the ZENITH study.

The elderly are at nutritional risk as a result of multiple physiological, social, psychological, and economic factors. Physiological functions naturally decline with age, which may influence absorption and metabolism. Social and economic conditions can adversely affect dietary choices and eating patterns. However, at the same time, the nutrient needs of the elderly for certain nutrient (such as vitamins, minerals, proteins) is higher than for younger adults. This article reviews the importance of zinc (Zn) in elderly people, particularly for behavioural and mental function, micronutrient status, immune and antioxidant system, and bone metabolism.

Estimation of intake and status of vitamin A, vitamin E and folate in older European adults: the ZENITH.

OBJECTIVE: To report selected dietary intake and vitamin status at baseline of volunteers participating in the ZENITH study and the correlation of vitamin status with zinc. DESIGN: A multicentre prospective intervention study employing a randomised double-blind design. SETTING: Clermont-Ferrand, Theix (France), Coleraine (Northern Ireland), Grenoble (France), Rome (Italy). PARTICIPANTS: In total, 387 healthy middle-aged (55-70 y) and older (70-87 y) men and women participated in the study. METHODS: Dietary intake was assessed by means of a validated 4-d recall record. Fasting blood samples were simultaneously analysed for retinol and alpha-tocopherol by the HLPC method. Erythrocyte folates were measured by a competitive immunoassay with direct chemiluminescence detection on an automatised immunoanalyser. RESULTS: In all centres, men had a significantly (P < 0.0001) higher mean nutrient intake than women. Comparison between age-groups showed that older individuals had significantly lower intakes of macro- and selected micronutrients than middle-aged subjects (P < 0.0001). A high fat intake (from 36 to 40% of total energy) was observed in all examined groups. In relation to biochemical measures of vitamin status, all parameters were above their respective cut-off values for normality and, thus, none of the subjects had biochemical evidence of deficiency of these selected vitamins. A moderate correlation was found with plasma vitamin A and serum zinc (r = 0.12, P < 0.05) or red blood cell zinc (r = 0.12, P < 0.01) and with erythrocyte folates and red blood cell zinc (r = 0.11, P < 0.05). CONCLUSIONS: There were only moderate differences in the nutrient intake of the ZENITH study volunteers among the four European centres. Their biochemical status for retinol, alpha-tocopherol and folate appeared adequate.

Introduction to the ZENITH study and summary of baseline results.

Zinc is known to be essential for a great number of biochemical activities and physiological and cognitive functions. The objective of Zenith study was to investigate the effects of Zn, as a nutritional supplement, on psychological and behavioural factors and on surrogate markers that are indicative of trends towards better health in order to evaluate the need for dietary recommendations specific to the studied population. We report in this paper the summary of baseline results obtained before Zn supplementation.

Age-related oxidative stress and antioxidant parameters in middle-aged and older European subjects: the ZENITH study.

OBJECTIVE: Oxidative stress has been reported to increase with ageing. However, the data in healthy humans remain controversial and studies in free-living elderly people are scarce. The objective of the present study was to compare age-related oxidative stress in late middle-aged and older free-living subjects. DESIGN: The effect of ageing on oxidative stress and antioxidant parameters was investigated in 188 middle-aged subjects from Clermont-Ferrand (France) and Coleraine (UK), and in 199 older subjects from Grenoble (France) and Roma (Italy). Plasma thiol (SH) groups, define definition (TBAR's) and total glutathione (GSH), define definition (FRAP), and superoxide dismutase (SOD) activity were measured at baseline of the ZENITH study. RESULTS: Plasma SH groups and FRAP and, surprisingly, TBAR's were significantly lower in free-living older subjects compared to younger subjects (P < 0.001, P < 0.001, P < 0.01, respectively), but there was no significant differences in GSH levels. CONCLUSION: European free-living healthy older do not appear to be exposed to an acute oxidative stress. However, the highly significant positive correlation between plasma SH group oxidation or decreased FRAP and ageing is predictive of an increased risk of oxidative stress in older subjects. Moreover, the comparison between middle-aged and older subjects regarding oxidative stress parameters suggests also a progressive and slow decline of antioxidant status in healthy free-living older elderly and underline the impact on life-style factors on successful ageing.

Screening and recruitment procedure of late-middle aged and older subjects: the ZENITH study.

OBJECTIVE: To report the rational, design, recruitment, baseline characteristics and preliminary overview of volunteers in the ZENITH study. DESIGN: A multicentre prospective intervention study employing a randomised double-blind design. SETTING: Clermont-Ferrand, Theix (France), Coleraine (Northern Ireland), Grenoble (France), Rome (Italy). PARTICIPANTS: Healthy men and women middle-aged (55-70 y) and older volunteers (70-87 y). INTERVENTIONS: At baseline (prior to zinc (Zn) supplementation), all volunteers underwent a full clinical examination, anthropometric measurements, health and lifestyle questionnaire, Mini Mental State Examination, Geriatric Depression Scale, and biochemistry profile. RESULTS: In total, 842 volunteers (378 men and 464 women) were invited to take part in the study. A total of 49% of these volunteers were excluded on the basis of inclusion/exclusion criteria. In total, 433 participants were admitted to the Zn supplementation for 6 months. During this period, about 10% of volunteers dropped out from the study. CONCLUSIONS: A total of 387 subjects (197 male and 190 female subjects) successfully completed the supplementation phase of the ZENITH study.

Effect of domestic cooking on human bioavailability of naringenin, chlorogenic acid, lycopene and beta-carotene in cherry tomatoes.

BACKGROUND: Epidemiological data showed that tomato and tomato product (sauce, paste) consumption is associated with a protective effect against the development of some chronic-degenerative diseases. Tomato antioxidant bioactive molecules such as carotenoids and polyphenols could be responsible, at least in part, for the healthy effect observed. The bioavailability of these compounds is an essential requirement to sustain their in vivo role. While it is well known that many factors can influence the bioaccessibility of carotenoids from the food matrix, there is little information about the factors affecting phenolic compounds' bioaccessibility. AIM OF THE STUDY: This investigation was carried out to evaluate the effect of domestic cooking on the bioavailability in humans of antioxidant molecules after the administration of a test meal containing cherry tomatoes. METHODS: A cross-over design was conducted. Subjects (3 females and 2 males) consumed experimental meals containing fresh and cooked cherry tomatoes. Blood collection was performed at different time intervals (0, 2, 4, 6, 8 and 24 h). RESULTS: Carotenoid and phenol plasma concentrations were measured. Plasma levels of lycopene and beta-carotene were not significantly different with respect to the baseline after ingestion of both the test meals, while plasma concentrations of naringenin and chlorogenic acid increased significantly with respect to the baseline (P<0.05) after administration of cooked cherry tomatoes, but not after administration of fresh cherry tomatoes. CONCLUSIONS: The present study indicated that domestically cooked tomatoes significantly increase naringenin and chlorogenic acid plasma levels. Considering that both naringenin and chlorogenic acid are widely studied for their potential healthy properties, evidence of their bioavailability and of the factors influencing their bioaccessibility is an important tool to sustain the possibility that these polyphenols play a biological role in human physiology.

Flavonoids uptake and their effect on cell cycle of human colon adenocarcinoma cells (Caco2).

Green tea, mainly through its constituents epigallocatechin gallate, epigallocatechin, epicatechin gallate and epicatechin, has demonstrated anticarcinogenic activity in several animal models, including those for skin, lung and gastro-intestinal tract cancer, although less is known about colorectal cancer. Quercetin, the major flavonoid present in vegetables and fruit, exerts potential anticarcinogenic effects in animal models and cell cultures, but less is known about quercetin glucosides. The objectives of this study were to investigate (i) the antioxidant activity of the phenolic compounds epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside; (ii) the cytotoxicity of different concentrations of epicatechin, epigallocatechin gallate, and gallic acid; (iii) the cellular uptake of epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside and (iv) their effect on the cell cycle. Human colon adenocarcinoma cells were used as experimental model. The results of this study indicate that all dietary flavonoids studied (epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside) show a significant antioxidant effect in a chemical model system, but only epigallocatechin gallate or gallic acid are able to interfere with the cell cycle in Caco2 cell lines. These data suggest that the antioxidant activity of flavonoids is not related to the inhibition of cellular growth. From a structural point of view, the galloyl moiety appears to be required for both the antioxidant and the antiproliferative effects.

Accumulation and interactions of beta-carotene and alpha-tocopherol in patients with adenomatous polyps.

OBJECTIVE: The aims of the present study were: (1) to determine whether short-term supplementation of beta-carotene (BC) or vitamin E (VE; alpha-tocopherol) would result in their respective accumulation in normal colonic mucosa and in adenomatous polyps; (2) to determine whether the intake of BC would interfere with the concentration of VE in these target tissues. DESIGN: Blood and colonic biopsy samples were taken before and after supplementation. SUBJECTS: Eighteen volunteers with colonic adenomatous polyps were enrolled into this study. INTERVENTIONS: The supplementation lasted for 43 days and patients were examined over the whole period. Subjects were randomised into four groups according to the four different supplementations: placebo, natural BC (25 000 IU/day), natural VE (400 IU/day), combination BC/VE. RESULTS: Initially we were aiming for recruitment of 20 patients in each group, however after 2 y of study (1997-1999), we terminated the study because of slow recruitment and analysed the data. In placebo subjects after supplementation, the plasma concentrations of BC and VE remained unchanged, however only two patients were recruited in this group and therefore we did not include this group in our final analysis. In BC group, the plasma BC concentrations increased significantly (P<0.001), while VE concentrations were unchanged. In VE group, VE concentrations increased (P<0.01) and BC did not change, and in BC/VE group both BC (P<0.001) and VE levels (P<0.01) increased significantly. After supplementation, the tissue concentration of BC in normal colonic mucosa in BC group increased significantly (P<0.01) while the VE concentration did not change. In VE group, the concentration of VE in normal colonic mucosa increased slightly but did not reach statistical significance. However, VE concentration increased significantly (P<0.05) in the polyps of this group. In BC/VE group, in which patients received the combination treatment, the BC concentration of normal colonic mucosa increased (P<0.05) but, surprisingly, the VE concentration decreased significantly (P<0.01). Interestingly in the polyps, although the BC concentration increased (P<0.01), the concentration of VE was reduced moderately but did not reach statistical significance. CONCLUSIONS: Supplementation of BC in doses used in this study may have significantly interfered with the VE concentration in the examined tissue and probably with its metabolic pathway.

A critical assessment of some biomarker approaches linked with dietary intake.

In this review many examples are given of the complexities involved in using some biomarkers in relation to assessing the effects of dietary exposure, when there is frequently a need to determine changes following long-term low level exposure to dietary components. These range from understanding why the biomarker might be valuable and how best it can be measured, to the pitfalls which can occur in the interpretation of data. Analytical technique is considered in relation to folate and selenium, and flavonoid and carotenoid species are used to illustrate how the metabolism of a compound may alter the validity or adequacy of a marker. Vitamin A is discussed in relation to the difficulties which can arise when there are several biomarkers that may be available to assess exposure to one nutrient. Vitamin B12 is discussed in relation to the dietary choices made by individuals. Possible interactions and the role of measuring total antioxidant capacity is considered in some detail. In contrast to most nutrients, there is a marked lack of biomarkers of either exposure or effect for most non-nutrients. The role of biological effect monitoring is considered for dietary contaminants, fumonisins and polyhalogenated aromatic hydrocarbons. Aflatoxins are discussed to exemplify food contaminants for which the biomarker approach has been extensively studied. Finally some compounds which are deliberately added to foods and some which appear as processing contaminants are each considered briefly in relation to the requirement for a biomarker of exposure to be developed.

High-performance liquid chromatography with coulometric electrode array detector for the determination of quercetin levels in cells of the immune system.

There is mounting evidence emphasizing the importance of intracellular antioxidant levels for maintenance of the immune function. The flavonoid quercetin, a natural antioxidant, has been shown to modulate enzymes involved in the regulation of the inflammatory response. However, up to now, there have been no studies describing quercetin levels in cells of the immune system. A gradient reversed-phase HPLC technique to identify and quantify intracellular levels of quercetin and its application in mice splenocytes are described. Mobile phases were a 0.01 M sodium phosphate monobasic solution adjusted to pH 2.8 with 85% orthophosphoric acid (buffer, Solvent A) and methanol (Solvent B) with a flow rate of 1 ml/min. An eight-channel coulometric electrode array detector was used. In vitro supplementation with increasing concentration of quercetin (25, 50, and 100 microM) raises intracellular quercetin levels in a dose-dependent manner. The method has the required features of specificity and sensitivity for monitoring quercetin uptake in cells of the immune system.