Associations between company at dinner and daily diet quality in Dutch men and women from the NQplus study.

BACKGROUND/OBJECTIVES: Consuming the evening meal in the company of others has been associated with overall diet quality. Nevertheless, studies on the association between type of company at dinner and diet quality in adults are scarce. SUBJECTS/METHODS: Dutch men (n=895) and women (n=845) aged between 20 and 70 years, included in a population-based observational study, were studied. Dietary intake was assessed by multiple 24-h recalls (6013 recalls) to estimate the Dutch Healthy Diet index (0-80 points) representing daily diet quality. Sex-specific linear mixed models adjusting for covariates were calculated. Out-of-home dinners and company at dinner were strongly associated (r=0.66), and hence in additional analyses, out-of-home dinners were excluded to avoid multicollinearity. RESULTS: Among men, daily diet quality was similar when dinners were consumed in company or consumed alone, but higher when dinner was accompanied by family (mean 46.0, s.e. 0.3) than when dinner was accompanied by others (mean 42.3, s.e. 0.7; P=0.001). Adjustment for dinner location attenuated this association, but it remained significant when excluding out-of-home dinners. Among women, daily diet quality was lower when dinner was consumed in company (mean 48.9, s.e. 0.3) than when consumed alone (mean 51.1, s.e. 0.6; P<0.001). Dinners consumed in the company of family were associated with higher daily diet quality (mean 49.3, s.e. 0.4) than dinners consumed with others (mean 45.7, s.e. 0.6; P=0.001). These associations persisted when excluding out-of-home dinners. CONCLUSIONS: Only among women, dinners consumed alone as compared with dinners in company were associated with higher diet quality. In both men and women, dinners consumed with family were associated with higher diet quality as compared with dinners with others.

Adherence to the Dutch dietary guidelines is inversely associated with 20-year mortality in a large prospective cohort study.

BACKGROUND/OBJECTIVES: The Dutch guidelines for a healthy diet aim to reduce major chronic diseases. However, supporting evidence on their overall association with all-cause and cause-specific mortality is limited. Recently, the Dutch Healthy Diet-index (DHD-index) has been developed to assess adherence to these guidelines. The aim was to examine the association between the DHD-index and all-cause mortality and deaths from cardiovascular disease (CVD), coronary heart disease (CHD), stroke and cancer. SUBJECTS/METHODS: We followed 3593 men and women aged 55 years and older enrolled in the Rotterdam Study, a population-based prospective cohort study, from baseline in 1990-1993 to 2011. A validated 170-item food frequency questionnaire at baseline was used to calculate the DHD-index score (maximum 90 points). Cox proportional hazard models were used to estimate hazard ratios (HRs) adjusting for age, sex, total energy intake, smoking and educational level. RESULTS: During the 20-year follow-up, 1831 (51%) deaths were reported. Mean DHD-index score was 60.6 (s.d. 10.6). The score was inversely associated with all-cause mortality (highest vs lowest quartile HR 0.77; 95% confidence interval (CI) 0.67, 0.89). Inverse but non-significant associations were observed for mortality due to CVD (HR 0.74; 95% CI 0.55, 1.01), CHD (HR 0.60; 95% CI 0.34, 1.06) and stroke (HR 0.67; 95% CI 0.36, 1.22), whereas no association was observed with cancer mortality (HR 0.99; 95% CI 0.90, 1.11). CONCLUSIONS: A higher level of adherence to the Dutch dietary guidelines, as assessed with the DHD-index, was associated with a lower risk of all-cause mortality, probably due to an inverse association with cardiovascular causes of death.

Large inter-individual variation in isoflavone plasma concentration limits use of isoflavone intake data for risk assessment.

BACKGROUND/OBJECTIVES: Isoflavones are present in soy foods and soy-based supplements. Despite low plasma isoflavone concentrations in the general Western population, concentrations in supplement users exceed those suggested to be beneficial for health in Asian populations, raising concerns for adverse effects. To aid risk assessment, quantification of the relation between isoflavone intake and plasma concentrations is essential. SUBJECTS/METHODS: Plasma samples were collected from postmenopausal women in three placebo-controlled crossover studies with 8-week periods for supplements (two studies, ~100 mg isoflavones/day, n=88) or 4-week periods for soy foods (one study, ~48 mg isoflavones/day, n=15). Plasma isoflavone concentrations (daidzein, equol, genistein and glycitein) were quantified using high-performance liquid chromatography and electrochemical detection. The association between plasma concentrations and isoflavone intake, equol producer status, intake-producer interaction and background dietary intake was assessed based on the assumption of a log-linear relation. RESULTS: Median plasma total isoflavone concentrations after the soy food and supplement interventions were respectively 2.16 and 3.47 µmol/l for equol producers and 1.30 and 2.39 µmol/l for non-producers. Regression analysis showed that doubling isoflavone intake increased plasma concentrations by 55-62% (±s.e. 1-2%, R(2)>0.87) for daidzein, genistein, equol (only for producers) and total isoflavones; for glycitein the association was weaker (15±1%, R(2)=0.48). Adjustments for energy, carbohydrate and fat intake did not affect these estimates. Inter-individual variation, estimated based on repeated measures in one of the studies, was 30-96%. CONCLUSIONS: Although the relation between isoflavone intake and plasma concentrations was adequately quantified, the use of isoflavone intake data for risk assessment needs caution due to large inter-individual variation in plasma concentrations.

Vitamin B12, folate, homocysteine, and bone health in adults and elderly people: a systematic review with meta-analyses.

Elevated homocysteine levels and low vitamin B12 and folate levels have been associated with deteriorated bone health. This systematic literature review with dose-response meta-analyses summarizes the available scientific evidence on associations of vitamin B12, folate, and homocysteine status with fractures and bone mineral density (BMD). Twenty-seven eligible cross-sectional (n = 14) and prospective (n = 13) observational studies and one RCT were identified. Meta-analysis on four prospective studies including 7475 people showed a modest decrease in fracture risk of 4% per 50 pmol/L increase in vitamin B12 levels, which was borderline significant (RR = 0.96, 95% CI = 0.92 to 1.00). Meta-analysis of eight studies including 11511 people showed an increased fracture risk of 4% per µ mol/L increase in homocysteine concentration (RR = 1.04, 95% CI = 1.02 to 1.07). We could not draw a conclusion regarding folate levels and fracture risk, as too few studies investigated this association. Meta-analyses regarding vitamin B12, folate and homocysteine levels, and BMD were possible in female populations only and showed no associations. Results from studies regarding BMD that could not be included in the meta-analyses were not univocal.

Evaluation of food and nutrient intake assessment using concentration biomarkers in European adolescents from the Healthy Lifestyle in Europe by Nutrition in Adolescence study.

Accurate food and nutrient intake assessment is essential for investigating diet-disease relationships. In the present study, food and nutrient intake assessment among European adolescents using 24 h recalls (mean of two recalls) and a FFQ (separately and the combination of both) were evaluated using concentration biomarkers. Biomarkers included were vitamin C, ß-carotene, DHA+EPA, vitamin B12 (cobalamin and holo-transcobalamin) and folate (erythrocyte folate and plasma folate). For the evaluation of the food intake assessment 390 adolescents were included, while 697 were included for the nutrient intake assessment evaluation. Spearman rank and Pearson correlations, and validity coefficients, which are correlations between intake estimated and habitual true intake, were calculated. Correlations were higher between frequency of food consumption (from the FFQ) and concentration biomarkers than between mean food intake (from the recalls) and concentration biomarkers, especially for DHA+EPA (r 0·35 v. r 0·27). Most correlations were higher among girls than boys. For boys, the highest validity coefficients were found for frequency of fruit consumption (0·88) and for DHA+EPA biomarker (0·71). In girls, the highest validity coefficients were found for fruit consumption frequency (0·76), vegetable consumption frequency (0·74), mean fruit intake (0·90) and DHA+EPA biomarker (0·69). After exclusion of underreporters, correlations slightly improved. Correlations between usual food intakes, adjusted for food consumption frequency, and concentration biomarkers were higher than correlations between mean food intakes and concentration biomarkers. In conclusion, two non-consecutive 24 h recalls in combination with a FFQ seem to be appropriate to rank subjects according to their usual food intake.

Rationale and methods of the European Food Consumption Validation (EFCOVAL) Project.

BACKGROUND/OBJECTIVES: The overall objective of the European Food Consumption Validation (EFCOVAL) Project was to further develop and validate a trans-European food consumption method to be used for the evaluation of the intake of foods, nutrients and potentially hazardous chemicals within the European population. SUBJECTS/METHODS: The EFCOVAL Project was carried out by 13 institutes from 11 European countries. The main activities were centered on the three main objectives of the project organized in different sub-projects. RESULTS: In EFCOVAL, EPIC-Soft (the software developed to conduct 24-h dietary recalls (24-HDRs) in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study) was reprogrammed and adapted according to prioritized specifications, resulting in a software program working under the Windows operating system. In parallel of the EPIC-Soft development, the repeated 24-HDR method using EPIC-Soft and a food propensity questionnaire was evaluated against biomarkers in 24-h urine collections and in blood samples among adults from Belgium, the Czech Republic, (the South of) France, the Netherlands and Norway. As a result from an expert workshop on a proposed dietary assessment method for children (4-12 years), the suggested method was tested in a feasibility study in Denmark and Spain among children of 4-5, 7-8 and 12-13 years. To ensure that collected data had sufficient detail in food description for the assessment of additives and contaminants to foods the EPIC-Soft databases were adapted. Finally, the EFCOVAL Consortium developed a statistical tool (Multiple Source Method) for estimating the usual intake and distribution, which has been tested using real food consumption data and compared with three other statistical methods through a simulation study. In addition, a methodology was developed to quantify uncertainty due to portion-size estimation in usual intake distributions. CONCLUSION: The findings of EFCOVAL provide sufficient evidence to conclude that the repeated 24-HDR using EPIC-Soft for standardization in combination with a food propensity questionnaire and modeling of usual intake is a suitable method for pan-European surveillance of nutritional adequacy and food safety among healthy adults and maybe in children aged 7 years and older.

The European Food Consumption Validation Project: conclusions and recommendations.

BACKGROUND/OBJECTIVES: To outline and discuss the main results and conclusions of the European Food Consumption Validation (EFCOVAL) Project. SUBJECTS/METHODS: The EFCOVAL Project was carried out within the EU Sixth Framework Program by researchers in 11 EU countries. The activities focused on (1) the further development of the EPIC-Soft software (the software developed to conduct 24-h dietary recalls (24-HDRs) in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study) and the validation of the 2-day non-consecutive 24-HDR method using EPIC-Soft, (2) defining and investigating the applicability of the most appropriate dietary assessment method to younger age groups and expanding the applicability of the software for use in exposure assessment of some potentially hazardous chemicals and (3) to improve the methodology and statistical methods that estimate usual intake distributions from short-term dietary intake information and develop a methodology to quantify uncertainty in usual intake distributions. RESULTS: The preexisting EPIC-Soft application was reprogrammed into a Windows environment and more than 60 new specifications were implemented in the software. A validation study showed that two non-consecutive EPIC-Soft 24-HDRs are suitable to estimate the usual intake distributions of protein and potassium of European adult populations. The 2-day non-consecutive 24-HDRs in combination with a food propensity questionnaire also appeared to be appropriate to rank individuals according to their fish and fruit and vegetable intake in a comparable way in five European centers. Dietary intake of (young) children can be assessed by the combination of EPIC-Soft 24-HDRs and food recording booklets. The EPIC-Soft-standardized method of describing foods is useful to estimate dietary exposure to potentially hazardous chemicals such as specific flavoring substances. With the developed Multiple Source Method, repeated non-consecutive 24-HDR data in combination with food propensity data can be used to estimate the population distribution of the usual intake by estimating the individual usual intakes. CONCLUSIONS: The findings provide sufficient evidence to conclude that the repeated 24-HDR using EPIC-Soft for standardization in combination with a food propensity questionnaire and modeling of usual intake is a suitable method for pan-European surveillance of nutritional adequacy and food safety among healthy adults and maybe in children aged 7 years and older. To facilitate this methodology in other European countries, the next step is to provide and standardize an implementation plan that accounts for maintenance and updates, sampling designs, national surveillance programs, tailored capacity building and training, and linkage to food composition and occurrence databases.

Biomarker-based evaluation of two 24-h recalls for comparing usual fish, fruit and vegetable intakes across European centers in the EFCOVAL Study.

BACKGROUND/OBJECTIVES: A standardized methodology is important to enable consistent monitoring of dietary intake across European countries. For this reason, we evaluated the comparability of the assessment of usual food intake collected with two non-consecutive computerized 24-h dietary recalls (24-HDRs) and a food propensity questionnaire (FPQ) among five European centers. SUBJECTS/METHODS: Two 24-HDRs using EPIC-Soft (the software developed to conduct 24-HDRs in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study) were performed to determine fish, fruit and vegetable (FV) consumed by 600 adults in Belgium (BE), the Czech Republic (CZ), France (FR), the Netherlands (NL) and Norway (NO) in a validation study. An FPQ was used to identify non-consumers. Information from the 24-HDRs and FPQ were used to estimate individual usual food intake by the Multiple Source Method (MSM). Blood samples were drawn to determine fatty acids in phospholipids and serum carotenoids as biomarkers of fish, and FV intake, respectively. RESULTS: The pooled correlation between usual fish intake and eicosapentaenoic acid plus docosahexaenoic acid in phospholipids was 0.19 in men and 0.31 in women (P for heterogeneity >0.50) and center-specific correlations ranged between 0.08 (CZ) and 0.28 (BE and NO) in men, and between 0.19 (BE) and 0.55 (FR) in women. For usual FV intake, the pooled correlation with serum carotenoids was 0.31 in men and 0.40 in women (P for heterogeneity >0.10); the center-specific correlations varied between 0.07 (NO) and 0.52 (FR) in men, and between 0.25 (NL) and 0.45 (NO) in women. CONCLUSION: Two standardized 24-HDRs using EPIC-Soft and an FPQ appeared to be appropriate to rank individuals according to their fish and FV intake in a comparable way among five European centers.

Comparing four methods to estimate usual intake distributions.

BACKGROUND/OBJECTIVES: The aim of this paper was to compare methods to estimate usual intake distributions of nutrients and foods. As 'true' usual intake distributions are not known in practice, the comparison was carried out through a simulation study, as well as empirically, by application to data from the European Food Consumption Validation (EFCOVAL) Study in which two 24-h dietary recalls (24-HDRs) and food frequency data were collected. The methods being compared were the Iowa State University Method (ISU), National Cancer Institute Method (NCI), Multiple Source Method (MSM) and Statistical Program for Age-adjusted Dietary Assessment (SPADE). SUBJECTS/METHODS: Simulation data were constructed with varying numbers of subjects (n), different values for the Box-Cox transformation parameter (λ(BC)) and different values for the ratio of the within- and between-person variance (r(var)). All data were analyzed with the four different methods and the estimated usual mean intake and selected percentiles were obtained. Moreover, the 2-day within-person mean was estimated as an additional 'method'. These five methods were compared in terms of the mean bias, which was calculated as the mean of the differences between the estimated value and the known true value. The application of data from the EFCOVAL Project included calculations of nutrients (that is, protein, potassium, protein density) and foods (that is, vegetables, fruit and fish). RESULTS: Overall, the mean bias of the ISU, NCI, MSM and SPADE Methods was small. However, for all methods, the mean bias and the variation of the bias increased with smaller sample size, higher variance ratios and with more pronounced departures from normality. Serious mean bias (especially in the 95th percentile) was seen using the NCI Method when r(var) = 9, λ(BC) = 0 and n = 1000. The ISU Method and MSM showed a somewhat higher s.d. of the bias compared with NCI and SPADE Methods, indicating a larger method uncertainty. Furthermore, whereas the ISU, NCI and SPADE Methods produced unimodal density functions by definition, MSM produced distributions with 'peaks', when sample size was small, because of the fact that the population's usual intake distribution was based on estimated individual usual intakes. The application to the EFCOVAL data showed that all estimates of the percentiles and mean were within 5% of each other for the three nutrients analyzed. For vegetables, fruit and fish, the differences were larger than that for nutrients, but overall the sample mean was estimated reasonably. CONCLUSIONS: The four methods that were compared seem to provide good estimates of the usual intake distribution of nutrients. Nevertheless, care needs to be taken when a nutrient has a high within-person variation or has a highly skewed distribution, and when the sample size is small. As the methods offer different features, practical reasons may exist to prefer one method over the other.

European micronutrient recommendations aligned: a general framework developed by EURRECA.

BACKGROUND: In Europe, micronutrient recommendations have been established by (inter)national committees of experts and are used by public health-policy decision makers to monitor and assess the adequacy of the diets of population groups. Current micronutrient recommendations are, however, heterogeneous, whereas the scientific basis for this is not obvious. Alignment of setting micronutrient recommendations is necessary to improve the transparency of the process, the objectivity and reliability of recommendations that are derived by diverse regional and (inter)national bodies. OBJECTIVE: This call for alignment of micronutrient recommendations is a direct result of the current sociopolitical climate in Europe and uncovers the need for an institutional architecture. There is a need for evidence-based policy making, transparent decision making, stakeholder involvement and alignment of policies across Europe. RESULTS: In this paper, we propose a General Framework that describes the process leading from assessing nutritional requirements to policy applications, based on evidence from science, stakeholder interests and the sociopolitical context. The framework envisions the derivation of nutrient recommendations as scientific methodology, embedded in a policy-making process that also includes consumer issues, and acknowledges the influences of the wider sociopolitical context by distinguishing the principal components of the framework: (a) defining the nutrient requirements for health, (b) setting nutrient recommendations, (c) policy options and (d) policy applications. CONCLUSION: The General Framework can serve as a basis for a systematic and transparent approach to the development and review of micronutrient requirements in Europe, as well as the decision making of scientific advisory bodies, policy makers and stakeholders involved in this process of assessing, developing and translating these recommendations into public health nutrition policy.

Prioritizing micronutrients for the purpose of reviewing their requirements: a protocol developed by EURRECA.

BACKGROUND: The EURRECA (EURopean micronutrient RECommendations Aligned) Network of Excellence (http://www.eurreca.org) is working towards the development of aligned recommendations. A protocol was required to assign resources to those micronutrients for which recommendations are most in need of alignment. METHODS: Three important 'a priori' criteria were the basis for ranking micronutrients: (A) the amount of new scientific evidence, particularly from randomized controlled trials; (B) the public health relevance of micronutrients; (C) variations in current micronutrient recommendations. A total of 28 micronutrients were included in the protocol, which was initially undertaken centrally by one person for each of the different population groups defined in EURRECA: infants, children and adolescents, adults, elderly, pregnant and lactating women, and low income and immigrant populations. The results were then reviewed and refined by EURRECA's population group experts. The rankings of the different population groups were combined to give an overall average ranking of micronutrients. RESULTS: The 10 highest ranked micronutrients were vitamin D, iron, folate, vitamin B12, zinc, calcium, vitamin C, selenium, iodine and copper. CONCLUSIONS: Micronutrient recommendations should be regularly updated to reflect new scientific nutrition and public health evidence. The strategy of priority setting described in this paper will be a helpful procedure for policy makers and scientific advisory bodies.

Nutri-RecQuest: a web-based search engine on current micronutrient recommendations.

BACKGROUND: The EURRECA (EURopean micronutrient RECommendations Aligned) Network of Excellence collated current micronutrient recommendations. A user-friendly tool, Nutri-RecQuest, was developed to allow access to the collated data and to create a database source for use in other nutritional software tools. METHODS: Recommendations, that is, intakes of micronutrients sufficient to meet the requirements of the majority of healthy individuals of that population, from 37 European countries/organizations and eight key non-European countries/regions comprising 29 micronutrients were entered into a database. General information on the source of the recommendations, as well scientific background information, was added. RESULTS: A user-friendly web-based interface was developed to provide efficient search, comparison, display, print and export functions. CONCLUSION: Easy access to existing recommendations through the web-based tool may be valuable for bodies responsible for setting recommendations, as well as for users of recommendations including scientists, policy makers, health professionals and industry. Adding related dietary reference values such as average nutrient requirements and upper limits may extend the utility of the tool.

Positive and negative experiences of social support and long-term mortality among middle-aged Dutch people.

This study investigated the relation between positive and negative experiences of social support and mortality in a population-based sample. Data were derived from Dutch men and women aged 20-59 years who participated in the Doetinchem Cohort Study in 1987-1991. Social support was measured at baseline and after 5 years of follow-up by using the Social Experiences Checklist indicating positive (n = 11,163) and negative (n = 11,161) experiences of support. Mortality data were obtained from 1987 until 2008. Cox proportional hazards regression models, adjusted for age and sex, showed that low positive experiences of support at baseline were associated with an increased mortality risk after, on average, 19 years of follow-up (hazard ratio = 1.26, 95% confidence interval: 1.04, 1.52). Even after additional adjustment for socioeconomic factors, lifestyle factors, and indicators of health status, the increased mortality risk remained statistically significant (hazard ratio = 1.23, 95% confidence interval: 1.01, 1.49). For participants with repeated measurements of social support at 5-year intervals, a stable low level of positive experiences of social support was associated with a stronger increase in age- and sex-adjusted mortality risk (hazard ratio = 1.57, 95% confidence interval: 1.03, 2.39). Negative experiences of social support were not related to mortality.

Dietary exposure to flavouring substances: from screening methods to detailed assessments using food consumption data collected with EPIC-Soft software.

This study aimed to compare different methods of assessing dietary exposure to flavourings in the context of a stepwise approach. The dietary exposure to four flavourings--raspberry ketone, glycyrrhizinic acid, coumarin, and caffeine--was determined. When dietary exposure exceeded the safety limits, the need for more detailed assessment using less aggregated data was judged necessary. First, screening methods--maximized survey-derived daily intake (MSDI), single-portion exposure technique (SPET), and modified theoretical added maximum daily intake (mTAMDI)--were applied. Next, individual food consumption data were used for creating models with different levels of detail to identify the foods: a model based on food groups and models based on food items. These were collected from 121 Dutch adults using a standardized 2 x 24-h dietary recall (EPIC-Soft) in the European Food Consumption Validation (EFCOVAL) study. Three food item models were developed: without improvements of the flavouring descriptor built in the software; with improvements; and with use of non-specified flavour descriptors. Based on the results of at least one of the three screening methods, refined assessment was necessary for raspberry ketone, glycyrrhizinic acid, and caffeine. When applying the food group model, the need for refinement was indicated for the four flavourings. When applying the food item models, only glycyrrhizinic acid and caffeine presented dietary exposure above the safety limits. In the raspberry ketone case, dietary exposure increased when improvements in food description were considered. The use of non-specified flavour descriptors hardly changed the results. The collection of detailed food consumption data at the individual level is useful in the dietary exposure assessment of these flavourings.

Characterization of different groups of elderly according to social engagement activity patterns.

OBJECTIVE: The aim of this research was to segment older people in subgroups with similar social engagement activity patterns in order to better target public health interventions. DESIGN: Cross-sectional data, collected in 2005 by Dutch community health services (response 79%), from 22026 independently living elderly aged 65 or older were used. Cluster analysis was performed to derive subgroups with common social engagement activity patterns, which were compared for their self-perceived health, mental health, physical health, and loneliness. RESULTS: Among the independently living older people, five subgroups were identified with different patterns of social engagement activities: less social engaged elderly, less social engaged caregivers, social engaged caregivers, leisure engaged elderly, and productive engaged elderly. The subgroups differed significantly in social engagement activities, socio-demographics, and health (p < 0.001). The groups with the highest relative numbers of older people who were frequently engaged in leisure and productive-related activities, also included relatively more elderly with a good self-perceived health (85.8% versus 58.8%), mental health (91.3% versus 74.6%), physical health (97.7% versus 73.0%), and elderly who were not lonely (70.0% versus 52.0%) when compared to the least healthy subgroup. CONCLUSION: Older people could be segmented in subgroups based on similar social engagement patterns. Groups with elderly who were less socially engaged demonstrate to be possible target groups for public health interventions, given the relatively high shares of unhealthy older people among them.

Personalized nutrition communication through ICT application: how to overcome the gap between potential effectiveness and reality.

The potential effectiveness of personalized nutrition communication through the Internet is promising in terms of addressing personal relevance, flexibility, interactive options and amount of people that can be reached. However, little research on the contribution to behaviour change has been done. The MyFood program at Wageningen University aims at providing insight into strategies to implement personalized nutrition communication through interactive tools. In this article we present the framework for research on social acceptance of personalized nutrition communication through interactive computer technology as part of the MyFood program.

Plasma carotenoid levels in Dutch men and women, and the relation with vegetable and fruit consumption.

OBJECTIVE: Fruit and vegetable intake is inversely associated with cancer risk in many epidemiological studies. Accurate assessment of consumption of these foods is difficult, and biomarkers of intake would overcome several drawbacks of currently used dietary assessment methods. Therefore, we investigated the relation between plasma carotenoids and usual vegetable and fruit intake. DESIGN: Plasma carotenoid concentrations were measured and vegetable, fruit and juice consumption was assessed by a food frequency questionnaire (FFQ) in a random sample of 591 Dutch men and women aged 20-59 y from the MORGEN-project, one of the contributions to the European Prospective Investigation into Cancer and Nutrition (EPIC)-study. RESULTS: In this sample of the general Dutch population, in both genders, relative to the other carotenoids, plasma beta-cryptoxanthin was the best indicator for fruit intake, and for the sum of vegetable, fruit and juice intake, while lutein concentrations best reflected intake of vegetables, although quartiles of intake were not consistently separated. Since levels of lycopene were not associated with any of the main food groups examined, associations with total carotenoids improved when excluding lycopene, and monotonously increasing plasma levels were seen for intakes of vegetables, of fruits, and of the sum of vegetables, fruits and juices. Several vegetable types and orange/grapefruit juice were associated with plasma levels of one of the carotenoids. CONCLUSION: Plasma carotenoids were only crude indicators of vegetable and fruit intake as assessed by a FFQ; beta-cryptoxanthin for fruit intake and lutein for vegetable intake. None of the plasma carotenoids could distinguish all four quartiles of vegetables, fruit and/or juice intake.

Determinants of skin sensitivity to solar irradiation.

BACKGROUND: Acute effects of UV irradiation include UV-induced erythema. Sunlight plays an important role in the development of skin cancer. Several predictive factors of UV-induced erythema could also be predictive for skin cancer. OBJECTIVE: Our objective was to quantitatively assess phenotypical and nutritional determinants of sensitivity to UV irradiation, as assessed by the minimal erythema dose (MED). DESIGN: We conducted a cross-sectional study among 335 volunteers. Sensitivity to UV irradiation was established through assessment of the MED. Phenotypical determinants, including skin melanin content, hair color and iris color were determined by skin reflectance spectrometry, a subjective questionnaire and an objective classification system, respectively. Furthermore, dietary exposure was measured by carotenoids, vitamin C, retinol and alpha-tocopherol in serum. RESULTS: Male subjects were found to be more sensitive to UV irradiation; that is, the MED was significantly lower compared to female subjects. Skin melanin content, which was positively associated with iris color in both sexes and with hair color in men, was the main phenotypical determinant of sensitivity to UV irradiation. No associations were found between serum carotenoids and MED in the total study group. Vitamin C was inversely associated with MED. However, associations between carotenoids concentrations and MED showed a positive trend in subjects with melanin values above and a negative trend in subjects below the median after adjustment for gender and total cholesterol. CONCLUSIONS: Skin melanin content and gender are important determinants of sensitivity to UV irradiation. No relation was found between serum carotenoids and MED in the total study group. The inverse association between vitamin C and MED was against our hypothesis. For the modifying effect of melanin on the association between carotenoids and MED, we do not have a clear biological explanation.

Tissue levels of fish fatty acids and risk of colorectal adenomas: a case-control study (Netherlands).

Epidemiological and animal studies have suggested that a high ratio of n-3 fish fatty acids to arachidonic acid (AA), might protect against colorectal carcinogenesis. Competition of n-3 and n-6 fatty acids, especially AA, for the enzyme cyclooxygenase-2 may be responsible for this effect. To examine the relation between fish intake and colorectal adenomas, data from a Dutch case-control study were analysed. All 52 cases and 57 controls filled out a food questionnaire, underwent a full colonic examination and have had a fat biopsy from the buttock. Intake of fish and fish fatty acids was inversely associated with colorectal adenomas although not statistically significant. For the ratio of fish fatty acids to AA, the ORs in the second and third tertile were 1.2 and 0.8 (p-trend = 0.78). Tissue levels of fish fatty acids were inversely associated and tissue levels of AA were positively associated with adenomas, although not statistically significant. However, the OR for the ratio of fish fatty acids to AA was 0.2 in the second and third tertile (p-trend = 0.002). In line with the hypothesis, a high ratio of fish fatty acids to AA in adipose tissue was associated with a lower risk of colorectal adenomas.