Sugar-sweetened beverage consumption and obesity in children's meta-analyses: reaching wrong answers for right questions.

BACKGROUND: Recent studies assert that sugar-containing drinks may play a key role in the etiology of obesity. However, scientific reviews show contradictory results. Whether there is just association or clear causation still is a matter of debate. It is also subject to discussion whether the quality/adequacy of the different studies may influence their outcome. OBJECTIVE: The aim of this study is to explore the most recent scientific evidence focused on sugar-sweetened beverages (SSB) and child obesity and to further analyze the adequacy of the meta-analyses in terms of their results, with special emphasis in the methodology, clarity and transparence of their procedures. METHODS: Only meta-analyses of randomized control trial studies were selected. The search was performed on PubMed and Cochrane Website until January, 2016. Adherence to PRISMA was assessed. RESULTS: Six meta-analyses were included. All of them showed some degree of evidence of heterogeneity in theirs pool estimates. Two of them showed a positive association between SSB and obesity but the other four found no association. The adherence to the PRISMA criteria was higher in two of the meta-analyses that showed opposite conclusions regarding the association or non-association of SSB and obesity in children. Thus, there is no relation between the adequacy of the meta-analyses to the PRISMA criteria and the results obtained. CONCLUSION: The use of meta-analysis as a scientific tool still demand more polishing, agreement and spread out use by researchers. SSB are being accused of being a main cause of the existing obesity, but this subject requires a broader approach that includes a thorough analysis of diet and lifestyle and a stronger body of scientific evidence based on data from epidemiological studies conducted in different populations.

Beverage Consumption Habits among the European Population: Association with Total Water and Energy Intakes.

BACKGROUND: Fluid and water intake have received limited attention in epidemiological studies. The aim of this study was to compare the average daily consumption of foods and beverages in adults of selective samples of the European Union (EU) population in order to understand the contribution of these to the total water intake (TWI), evaluate if the EU adult population consumes adequate amounts of total water (TW) according to the current guidelines, and to illustrate the real water intake in Europe. METHODS: Three national European dietary surveys have been selected: Spain used the Anthropometry, Intake, and Energy Balance Study (ANIBES) population database, Italy analyzed data from the Italian National Food Consumption Survey (INRAN-SCAI 2005-06), and French data came from the NutriNet-Santé database. Mean daily consumption was used to compare between individuals. TWI was compared with European Food Safety Authority (EFSA) reference values for adult men and women. RESULTS: On average, in Spain, TWI was 1.7 L (SE 22.9) for men and 1.6 L (SE 19.4) for women; Italy recorded 1.7 L (SE 16.9) for men and 1.7 L (SE 14.1) for women; and France recorded 2.3 L (SE 4.7) for men and 2.1 L (SE 2.4) for women. With the exception of women in France, neither men nor women consumed sufficient amounts of water according to EFSA reference values. CONCLUSIONS: This study highlights the need to formulate appropriate health and nutrition policies to increase TWI in the EU population. The future of beverage intake assessment requires the use of new instruments, techniques, and the application of the new available technologies.

Reply to C. Ferreira-Pêgo's Letter to the Editor Re: Nissensohn M. et al.; Nutrients 2016, 8, 232.

n/a.

Beverage Consumption Habits around the World: The Burden of Disease Attributable to Hydration.

Dehydration occurs when the body loses more water than is taken in.[...].

Beverage Intake Assessment Questionnaire: Relative Validity and Repeatability in a Spanish Population with Metabolic Syndrome from the PREDIMED-PLUS Study.

We assess the repeatability and relative validity of a Spanish beverage intake questionnaire for assessing water intake from beverages. The present analysis was performed within the framework of the PREDIMED-PLUS trial. The study participants were adults (aged 55-75) with a BMI ≥27 and <40 kg/m², and at least three components of Metabolic Syndrome (MetS). A trained dietitian completed the questionnaire. Participants provided 24-h urine samples, and the volume and urine osmolality were recorded. The repeatability of the baseline measurement at 6 and 1 year was examined by paired Student's t-test comparisons. A total of 160 participants were included in the analysis. The Bland-Altman analysis showed relatively good agreement between total daily fluid intake assessed using the fluid-specific questionnaire, and urine osmolality and 24-h volume with parameter estimates of -0.65 and 0.22, respectively (R² = 0.20; p < 0.001). In the repeatability test, no significant differences were found between neither type of beverage nor total daily fluid intake at 6 months and 1-year assessment, compared to baseline. The proposed fluid-specific assessment questionnaire designed to assess the consumption of water and other beverages in Spanish adult individuals was found to be relatively valid with good repeatability.

Comparison of beverage consumption in adult populations from three different countries: do the international reference values allow establishing the adequacy of water and beverage intakes?

INTRODUCTION: Recommendations of adequate total water intake (aTWI) have been proposed by the European Food Safety Agency (EFSA) and the Institute of Medicine (IOM)of the United States of America. However, there are differences in the approach used to support them: IOM recommendation is based on average intakes observed in NHANES III (Third National Health and Nutrition Examination Survey) and EFSA recommendation on a combination of observed intakes from 13 different European countries. Despite these recommendations of aTWI, the currently available scientifi c evidence is not sufficient to establish a cut-off value that would prevent disease, reduce the risk for chronic diseases or improve health status. OBJECTIVE: To compare the average daily consumption of fluids (water and other beverages) in selective samples of population from Mexico, US and Spain, evaluating the quantity of fluid intake and understanding the contribution of each fluid type to the total fl uid intake. We also aim to determine if they reached adequate intake (AI) values, as defi ned by three different criteria: IOM, EFSA and water density. METHODS: Three studies were compared: from Mexico, the National Health and Nutrition Survey conducted in 2012 (NHNS 2012); from US, the NHANES III 2005-2010 and from Spain the ANIBES study leaded in 2013. Different categories of beverages were used to establish the pattern of energy intake for each country. Only adult population was selected. TWI of each study was compared with EFSA and IOM AI recommendations, as well as applying the criterion of water density (mL/kcal). RESULTS: The American study obtained the higher value of total kcal/day from food and beverages (2,437 ± 13). Furthermore, the percentage of daily energy intake coming from beverages was, for American adults, 21%. Mexico was slightly behind with 19% and Spain ANIBES study registered only 12%. ANIBES showed signifi cantly low AI values for the overall population, but even more alarming in the case of males. Only 12% of men, in contrast with 21% of women, do satisfy the EFSA criterion. The IOM criterion reaches even less with higher recommended values for daily intake. In contrast, 60% of the American population reached the recommended intake of the IOM criterion. However, available data did not allow calculating the percentage reached by the EFSA criterion. Data from the Mexican study did not permit conducting comparisons with IOM or with EFSA. However, the water density criteria (mL/kcal) was higher than 1. CONCLUSION: There is a notable difference between all three populations in terms of TWI. Furthermore, within the same population, values of adequacy of TWI changed signifi cantly when they were assessed using different criteria. More scientifi c evidence is required for the production of better defined water intake recommendations in the future as well as more studies focusing on beverage consumption patterns in different settings.

Beverage Consumption Habits and Association with Total Water and Energy Intakes in the Spanish Population: Findings of the ANIBES Study.

BACKGROUND: Inadequate hydration is a public health issue that imposes a significant economic burden. In Spain, data of total water intake (TWI) are scarce. There is a clear need for a national study that quantifies water and beverage intakes and explores associations between the types of beverages and energy intakes. METHODS: The Anthropometry, Intake and Energy Balance Study ANIBES is a national survey of diet and nutrition conducted among a representative sample of 2285 healthy participants aged 9-75 years in Spain. Food and beverage intakes were assessed in a food diary over three days. Day and time of beverage consumption were also recorded. RESULTS: On average, TWI was 1.7 L (SE 21.2) for men and 1.6 L (SE 18.9) for women. More than 75% of participants had inadequate TWI, according to European Food Safety Authority (EFSA) recommendations. Mean total energy intake (EI) was 1810 kcal/day (SE 11.1), of which 12% was provided by beverages. Water was the most consumed beverage, followed by milk. The contribution of alcoholic drinks to the EI was near 3%. For caloric soft drinks, a relatively low contribution to the EI was obtained, only 2%. Of eight different types of beverages, the variety score was positively correlated with TWI (r = 0.39) and EI (r = 0.23), suggesting that beverage variety is an indicator of higher consumption of food and drinks. CONCLUSIONS: The present study demonstrates that well-conducted surveys such as the ANIBES study have the potential to yield rich contextual value data that can emphasize the need to undertake appropriate health and nutrition policies to increase the total water intake at the population level promoting a healthy Mediterranean hydration pattern.

The Effect of the Mediterranean Diet on Hypertension: A Systematic Review and Meta-Analysis.

OBJECTIVE: The adoption of a Mediterranean diet (MD) pattern of eating is often described as a strategy to help prevent or manage hypertension. However, this dietary regimen has not been reviewed systematically for its efficacy against hypertension. Therefore, the purpose of this study was to analyze the effect of interventions of at least 1 year duration on blood pressure (BP) values through a systematic review and meta-analysis. The focus was on interventions comparing an MD with a low-fat diet. DESIGN: The authors accessed and searched PubMed and Scopus databases up to March, 2015. Randomized control trials comparing MD vs low-fat diet were included. The researchers assessed the methodological quality, extracted the valid data, and conducted the meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. RESULTS: Six trials (more than 7,000 individuals) were identified. Meta-analysis showed that interventions aiming at adopting an MD pattern for at least 1 year reduced both the systolic BP and diastolic BP levels in individuals with normal BP or mild hypertension. The effect was higher for the systolic BP (-1.44 mm Hg) but also consistent for the diastolic BP (-0.70 mm Hg). However, the results have to be interpreted with caution owing to the reduced number of studies eligible for inclusion in this meta-analysis. This situation limited the statistical power of the analyses. Furthermore, in all analyses, the pooled effect estimation showed a high evidence of heterogeneity, which compromises the validity of the pooled estimates. CONCLUSIONS AND IMPLICATIONS: A positive and significant association was found between the MD and BP in adults. However, in all cases the magnitude of the effect was small. Based on this limited group of studies and their heterogeneity, the authors found insufficient convincing evidence to suggest that the MD decreased BP. Further standardized research is urgently needed to reach evidence-based conclusions to clarify the role of MD in BP management, particularly in Europe and other societies where prevalence of cardiovascular diseases is increasing.

Assessment of beverage intake and hydration status.

UNLABELLED: Water is the main constituent of the human body. It is involved in practically all its functions. It is particularly important for thermoregulation and in the physical and cognitive performance. Water balance reflects water intake and loss. Intake of water is done mainly through consumption of drinking water and beverages (70 to 80%) plus water containing foods (20 to 30%). Water loss is mainly due to excretion of water in urine, faeces and sweat. The interest in the type and quantity of beverage consumption is not new, and numerous approaches have been used to assess beverage intake, but the validity of these approaches has not been well established. There is no standardized questionnaire developed as a research tool for the evaluation of water intake in the general population. Sometimes, the information comes from different sources or from different methodological characteristics which raises problems of the comparability. In the European Union, current epidemiological studies that focus exclusively on beverage intake are scarce. Biomarkers of intake are able to objectively assess dietary intake/status without the bias of self-reported dietary intake errors and also overcome the problem of intra-individual diet variability. Furthermore, some methods of measuring dietary intake used biomarkers to validate the data it collects. Biological markers may offer advantages and be able to improve the estimates of dietary intake assessment, which impact into the statistical power of the study. There is a surprising paucity of studies that systematically examine the correlation of beverages intake and hydration biomarker in different populations. A pilot investigation was developed to evaluate the comparative validity and reliability of newly developed interactive multimedia (IMM) versions compared to validated paper-administered (PP) versions of the Hedrick et al. beverage questionnaire. The study showed that the IMM appears to be a valid and reliable measure to assess habitual beverage intake. Similar study was developed in China, but in this case, the use of Smartphone technology was employed for beverage assessment. CONCLUSION: The methodology for measuring beverage intake in population studies remains controversial. There are few validated and reproducible studies, so there is still lacking an ideal method (ie, short, easy to administer, inexpensive and accurate) in this regard. Clearly, this is an area of scientific interest that is still in development and seems to be very promising for improving health research.

El agua es el principal constituyente del cuerpo humano. Está implicado en prácticamente la totalidad de sus funciones. Es especialmente importante en la termorregulación y en el rendimiento físico y cognitivo. El balance de agua refleja la ingesta y la pérdida de agua. La ingesta se realiza principalmente a través del consumo de agua potable y de bebidas (70 a 80%) más el agua que contienen los alimentos (20 a 30%). La pérdida de agua se realiza gracias a su excreción a través de la orina, las heces y el sudor. El interés por el tipo y la cantidad de bebidas consumidas no es nuevo, y numerosos enfoques se han utilizado para evaluarla, pero la validez de estos enfoques no se han establecido correctamente. Aún no existe, en población general, un cuestionario estandarizado desarrollado como herramienta de investigación para la evaluación de la ingesta de agua. El uso de información de diferentes fuentes y diferentes características metodológicas plantea problemas de comparabilidad entre estudios. En Europa los estudios epidemiológicos actuales que se centran exclusivamente en el consumo de bebidas son escasos. Los biomarcadores de ingesta permiten evaluar objetivamente la ingesta dietética sin el sesgo producido por los errores del auto-reporte. Además permiten superar el problema de la variabilidad intra-individual. Algunos métodos para medir ingesta alimentaria utilizan biomarcadores para validar los datos que recoge. Los marcadores biológicos ofrecen ventajas y son capaces de mejorar las estimaciones de la evaluación de ingesta dietética. Sin embargo, existen muy pocos estudios que examinen sistemáticamente la correlación entre la ingesta de bebidas y los biomarcadores de hidratación en diferentes poblaciones. Utilizando el cuestionario de bebidas de Hedrick y col. se realizó un estudio piloto para evaluar la validez y fiabilidad de un modelo multimedia interactivo (IMM) y para compararlo con una versión en papel-auto administrado (PP). El estudio mostró que el IMM parece ser un modelo válido y fiable para evaluar la ingesta de bebidas habitual. Un estudio similar se realizó en China, pero en este caso, se empleó para evaluar ingesta de bebidas la tecnología Smartphone. Conclusión: La metodología para valorar el consumo de bebidas en estudios poblacionales sigue siendo un tema controvertido. Existen pocos estudios validados y reproducibles, por lo que todavía no se dispone de un método ideal (corto, fácil de administrar, económico y preciso). Esta es un área de interés científico que aún está en desarrollo y que parece ser muy prometedora para mejorar las investigaciones en el área de la salud.

EURRECA-Estimating zinc requirements for deriving dietary reference values.

Zinc was selected as a priority micronutrient for EURRECA, because there is significant heterogeneity in the Dietary Reference Values (DRVs) across Europe. In addition, the prevalence of inadequate zinc intakes was thought to be high among all population groups worldwide, and the public health concern is considerable. In accordance with the EURRECA consortium principles and protocols, a series of literature reviews were undertaken in order to develop best practice guidelines for assessing dietary zinc intake and zinc status. These were incorporated into subsequent literature search strategies and protocols for studies investigating the relationships between zinc intake, status and health, as well as studies relating to the factorial approach (including bioavailability) for setting dietary recommendations. EMBASE (Ovid), Cochrane Library CENTRAL, and MEDLINE (Ovid) databases were searched for studies published up to February 2010 and collated into a series of Endnote databases that are available for the use of future DRV panels. Meta-analyses of data extracted from these publications were performed where possible in order to address specific questions relating to factors affecting dietary recommendations. This review has highlighted the need for more high quality studies to address gaps in current knowledge, in particular the continued search for a reliable biomarker of zinc status and the influence of genetic polymorphisms on individual dietary requirements. In addition, there is a need to further develop models of the effect of dietary inhibitors of zinc absorption and their impact on population dietary zinc requirements.

Beverage and water intake of healthy adults in some European countries.

INTRODUCTION: Nutritional surveys frequently collect some data of consumption of beverages; however, information from different sources and different methodologies raises issues of comparability. The main objective of this review was to examine the available techniques used for assessing beverage intake in European epidemiological studies and to describe the most frequent method applied to assess it. MATERIALS AND METHODS: Information of beverage intake available from European surveys and nutritional epidemiological investigations was obtained from gray literature. RESULTS: Twelve articles were included and relevant data were extracted. The studies were carried out on healthy adults by different types of assessments. The most frequent tool used was a 7-d dietary record. Only Germany used a specific beverage assessment tool (Beverage Dietary History). CONCLUSION: From the limited data available and the diversity of the methodology used, the results show that consumption of beverages is different between countries. Current epidemiological studies in Europe focusing on beverage intake are scarce. Further research is needed to clarify the amount of beverage intake in European population.

Effect of zinc intake on serum/plasma zinc status in infants: a meta-analysis.

A systematic review and meta-analysis of available randomised controlled trials (RCTs) was conducted to evaluate the effect of zinc (Zn) intake on serum/plasma Zn status in infants. Out of 5500 studies identified through electronic searches and reference lists, 13 RCTs were selected after applying the exclusion/inclusion criteria. The influence of Zn intake on serum/plasma Zn concentration was considered in the overall meta-analysis. Other variables were also taken into account as possible effect modifiers: doses of Zn intake, intervention duration, nutritional status and risk of bias. The pooled ß of status was 0.09 [confidence interval (CI) 0.05 to 0.12]. However, a substantial heterogeneity was present in the analyses (I(2) = 98%; P = 0.00001). When we performed a meta-regression, the effect of Zn intake on serum/plasma Zn status changed depending on the duration of the intervention, the dose of supplementation and the nutritional situation (P ANCOVA = 0.054; <0.001 and <0.007, respectively). After stratifying the sample according to the effect modifiers, the results by duration of intervention showed a positive effect when Zn intake was provided during medium and long periods of time (4-20 weeks and >20 weeks). A positive effect was also seen when doses ranged from 8.1 to 12 mg day(-1). In all cases, the pooled ß showed high evidence of heterogeneity. Zn supplementation increases serum/plasma Zn status in infants, although high evidence of heterogeneity was found. Further standardised research is urgently needed to reach evidence-based conclusions to clarify the role of Zn supplementation upon infant serum/plasma Zn status, particularly in Europe.

Association between vitamin B12 intake and EURRECA's prioritized biomarkers of vitamin B12 in young populations: a systematic review.

OBJECTIVE: To review evidence on the associations between vitamin B12 intake and its biomarkers, vitamin B12 intake and its functional health outcomes, and vitamin B12 biomarkers and functional health outcomes. DESIGN: A systematic review was conducted by searching electronic databases, until January 2012, using a standardized strategy developed in the EURRECA network. Relevant articles were screened and sorted based on title and abstract, then based on full text, and finally included if they met inclusion criteria. A total of sixteen articles were included in the review. SETTING: Articles covered four continents: America (n 4), Europe (n 8), Africa (n 1) and Asia (n 3). SUBJECTS: Population groups included healthy infants, children and adolescents, and pregnant and lactating women. RESULTS: From the total number of 5815 papers retrieved from the initial search, only sixteen were eligible according to the inclusion criteria: five for infants, five for children and adolescents, and six for pregnant and lactating women. CONCLUSIONS: Only one main conclusion could be extracted from this scarce number of references: a positive association between vitamin B12 intake and serum vitamin B12 in the infant group. Other associations were not reported in the eligible papers or the results were not provided in a consistent manner. The low number of papers that could be included in our systematic review is probably due to the attention that is currently given to research on vitamin B12 in elderly people. Our observations in the current systematic review justify the idea of performing well-designed studies on vitamin B12 in young populations.

Validation of beverage intake methods vs. hydration biomarkers; a short review.

INTRODUCTION: Fluid intake is difficult to monitor. Biomarkers of beverage intake are able to assess dietary intake/hydration status without the bias of self-reported dietary intake errors and also the intra-individual variability. Various markers have been proposed to assess hydration, however, to date; there is a lack of universally accepted biomarker that reflects changes of hydration status in response to changes in beverage intake. AIM: We conduct a review to find out the questionnaires of beverage intake available in the scientific literature to assess beverage intake and hydration status and their validation against hydration biomarkers. METHODS: A scientific literature search was conducted. Only two articles were selected, in which, two different beverage intake questionnaires designed to capture the usual beverage intake were validated against Urine Specific Gravidity biomarker (Usg). RESULTS: Water balance questionnaire (WBQ) reported no correlations in the first study and the Beverage Intake Questionnaire (BEVQ), a quantitative Food frequency questionnaire (FFQ) in the second study, also found a negative correlation. FFQ appears to measure better beverage intake than WBQ when compared with biomarkers. However, the WBQ seems to be a more complete method to evaluate the hydration balance of a given population. CONCLUSIONS: Further research is needed to understand the meaning of the different correlations between intake estimates and biomarkers of beverage in distinct population groups and environments.

Resumen: Introducción: La ingesta de líquidos es difícil de monitorear. Los biomarcadores de ingesta de bebidas son capaces de evaluar la ingesta dietética / estado de hidratación sin el sesgo producido por los errores de los auto- registros de ingesta dietaria, así como por la variabilidad intra-individual. Se han propuesto diversos marcadores para evaluar el estado de hidratación; sin embargo, hasta la fecha, no existe ningún biomarcador universalmente aceptado que refleje los cambios del estado de hidratación en respuesta a cambios en la ingesta de bebidas. Objetivo: Hemos llevado a cabo una revisión para determinar los cuestionarios de ingesta de bebidas disponibles en la literatura científica que evalúan la ingesta de bebidas y el estado de hidratación y que han sido validados con biomarcadores de hidratación. Métodos: Se realizó una búsqueda bibliográfica en la literatura científica. Se seleccionaron sólo dos artículos, los cuales contenían dos cuestionarios de ingesta de bebidas diferentes, diseñados para capturar la ingesta habitual de bebidas. Ambos cuestionarios fueron validados con el biomarcador Gravedad específica de la orina (Usg). Resultados: El Cuestionario de Balance Hídrico (WBQ) no reportó correlaciones en el primer estudio y el Cuestionario de Ingesta de Bebidas (BEVQ), que es un cuestionario de frecuencia de consumo alimentario (FFQ) en el segundo estudio, tampoco encontró una correlación positiva. El FFQ parece medir mejor la ingesta de bebidas que el WBQ en comparación con los biomarcadores. Sin embargo, el WBQ parece ser un método más completo para evaluar el balance hídrico de una población dada. Conclusión: Se necesita más investigación para entender el significado de las diferentes correlaciones entre las estimaciones de ingesta y los biomarcadores de bebidas en distintos grupos de población y en diferentes entornos.

Effect of zinc intake on mental and motor development in infants: a meta-analysis.

A systematic review and meta-analysis of available randomized controlled trials (RCTs) was conducted to evaluate the effect of zinc (Zn) intake on mental and motor development in infants. Out of 5500 studies identified through electronic searches and reference lists, 5 RCTs were selected after applying the exclusion/inclusion criteria. The influence of Zn intake on mental and motor development was considered in the overall meta-analysis. Other variables were also taken into account as possible effect modifiers: doses of Zn intake, intervention duration, nutritional situation, and risk of bias. Indices of mental and motor development assessed were the Mental Development Index (MDI) and Psychomotor Development Index (PDI). Additionally we carried out a sensitivity analysis. The pooled ß was -0.01 (95 %CI -0.02, 0) for MDI and 0 (95 %CI -0.03, 0.02) for PDI, with a substantial heterogeneity in both analyses. When we performed a meta-regression, the effect of Zn supplementation on MDI changed depending on the dose of supplementation. Regarding PDI, there was a differential effect of Zn intake depending on intervention duration, dose of supplementation, nutritional situation, and risk of bias. Zn supplementation showed a negative, weak and significant effect on PDI score in those studies with a length of 4 to 20 weeks (ß= -0.05; CI 95 % -0.06 to -0.04). In conclusion, no association was found between Zn intake and mental and motor development in infants. Further standardized research is urgently needed to clarify the role of Zn supplementation upon infant mental and motor development, particularly in Europe.

The relationship between zinc intake and serum/plasma zinc concentration in adults: a systematic review and dose-response meta-analysis by the EURRECA Network.

Dietary Zn recommendations vary widely across Europe due to the heterogeneity of approaches used by expert panels. Under the EURopean micronutrient RECommendations Aligned (EURRECA) consortium a protocol was designed to systematically review and undertake meta-analyses of research data to create a database that includes 'best practice' guidelines which can be used as a resource by future panels when setting micronutrient recommendations. As part of this process, the objective of the present study was to undertake a systematic review and meta-analysis of previously published data describing the relationship between Zn intake and status in adults. Searches were performed of literature published up to February 2010 using MEDLINE, Embase and the Cochrane Library. Data extracted included population characteristics, dose of Zn, duration of study, dietary intake of Zn, and mean concentration of Zn in plasma or serum at the end of the intervention period. An intake-status regression coefficient (ß ) was estimated for each individual study, and pooled meta-analysis undertaken. The overall pooled ß for Zn supplementation on serum/plasma Zn concentrations from randomised controlled trials and observational studies was 0·08 (95 % CI 0·05, 0·11; P < 0·0001; I² 84·5 %). An overall ß of 0·08 means that for every doubling in Zn intake, the difference in Zn serum or plasma concentration is ß (2(0·08) = 1·06), which is 6 %. Whether the dose-response relationship, as provided in the present paper, could be used as either qualitative or quantitative evidence to substantiate the daily Zn intake dose necessary to achieve normal or optimal levels of biomarkers for Zn status remains a matter of discussion.

The relationship between zinc intake and serum/plasma zinc concentration in children: a systematic review and dose-response meta-analysis.

Recommendations for zinc intake during childhood vary widely across Europe. The EURRECA project attempts to consolidate the basis for the definition of micronutrient requirements, taking into account relationships among intake, status and health outcomes, in order to harmonise these recommendations. Data on zinc intake and biomarkers of zinc status reported in randomised controlled trials (RCTs) can provide estimates of dose-response relationships which may be used for underpinning zinc reference values. This systematic review included all RCTs of apparently healthy children aged 1-17 years published by February 2010 which provided data on zinc intake and biomarkers of zinc status. An intake-status regression coefficient (ß) was calculated for each individual study and calculated the overall pooled and SE (ß) using random effects meta-analysis on a double log scale. The pooled dose-response relationship between zinc intake and zinc status indicated that a doubling of the zinc intake increased the serum/plasma zinc status by 9%. This evidence can be utilised, together with currently used balance studies and repletion/depletion studies, when setting zinc recommendations as a basis for nutrition policies.

Dietary methods and biomarkers of omega 3 fatty acids: a systematic review.

The aims of the present study were to review the validity of dietary methods used to measure the usual long chain (LC) omega-3 polyunsaturated fatty acid (n-3 PUFA) intake of a population and to assess the usefulness of different biomarkers of n-3 PUFA in healthy humans. Two systematic literature searches were conducted until May 2011 to update previous systematic reviews. The first literature search aimed to find studies validating the methodology used for measuring the dietary intake of n-3 PUFA. The second search aimed to find human intervention studies in which n-3 PUFA status changed after 2 weeks of n-3 PUFA supplementation. Sixteen studies were identified for inclusion in the first review. Correlation coefficients between fatty acids in subcutaneous fat or blood lipids and dietary intake of n-3 PUFA from different questionnaires were similar. Subcutaneous fat has been reported as the best reference method for some authors, and these studies showed moderate correlation coefficients with no dietary intake method being superior to any other. As for the evaluation of biomarkers of docosahexaenoic acid (DHA, 22 : 6 n-3) and eicosapentaenoic acid (EPA, 20 : 5n-3) status in response to supplementation, the new search reaffirmed and reinforced the evidence supporting that plasma phospholipid DHA, erythrocyte DHA, and platelet DHA were all effective and robust biomarkers of DHA status. Our findings only confirmed earlier studies and did not provide evidence for reaching new conclusions.

Methodological aspects of the study of dietary patterns during pregnancy and maternal and infant health outcomes. A systematic review.

The objective of the present study was to systematically review the literature exploring the associations between different dietary patterns obtained from Food Frequency Questionnaires during pregnancy and the development of health-related maternal and infant outcomes in the Framework of the EURRECA Network of Excellence. A systematic search was conducted on Pubmed for literature published up to September 2009. The search strategy resulted in an initial amount of 2048 articles. After applying the selection criteria, seven studies were finally identified. Five articles were based on prospective cohort studies and the other two were case-control studies. The methods used to elaborate the dietary pattern could be classified as hypothesis-oriented (three studies) or empirically-derived (four studies). The different food frequency questionnaires used for diet assessment were self-administered, semi-quantitative and had been previously validated, but just four studies employed questionnaires validated specifically for their use in a pregnant population. The divergent methods used to assess the dietary patterns make it difficult to compare results. However, some resulting recommendations can be applied when dietary patterns during pregnancy are analyzed: to employ a validated food frequency questionnaire designed for use in pregnancy, to consider the special role exerted by mineral and vitamin supplements in this particular population group, to adequately select the time in which dietary data is collected, to adjust the results for life-style and educational characteristics, and in the case of hypothesis-oriented dietary patterns, to correctly choose the components comprising the score.