Lead levels in retail samples of spanish infant formulae and their contribution to dietary intake of infants

Lead concentrations in a total of 82 different types of infant formulae (cow’s milk and soy based) marked in Spain were analysed by acid-microwave decomposition and anodic stripping voltammetry. Dietary lead intake from infant formula and tap water used for powder formula reconstitution were estimated in comparison with the provisional tolerable weekly intake (PTWI). Additionally, the influence of physical state (powder and ready to use formulae), the type of container used and the impact of industrial process from different manufacturers on lead levels were evaluated. According to our results, lead exposure from drinking water was negligible with respect to formulae investigated; where soya formulae contributed the highest intake (58 – 73 % PTWI), non adapted starter and specialised formulae gave an moderate intake (31 – 42 and 26 – 37 % PTWI, respectively) and, finally, pre-term, adapted starter and follow up formulae provided the lowest lead intake (22 – 25, 22 – 26 and 16 – 22 % PTWI, respectively). Based on the current state of knowledge about lead toxicity, manufacturers are called to make an additional effort in order to keep a maximum lead level at 20 g l-1 for all infant formulae, although it is recommendable that these formulations supply the upper limit (5 g l-1) of “normal” human milk

Selenium Content of Spanish Infant Formulae and Human Milk: Influence of Protein Matrix, Interactions with Other Trace Elements and Estimation of Dietary Intake by Infants

The Selenium content of infant formulae varies as a result of differences in the amount of intrinsic selenium compounds. Manufacturers have been gradually changing the protein profile of infant formula to reflect human milk contents more closely. Because of these variations in infant formula composition and their potential impact on selenium content, this trace element was analysed with regard to the different protein sources. The aims of this study were to determine the selenium content in infant formulae sold commercially in Spain, to estimate a daily dietary intake for infants fed on formulae and to compare with the selenium provided by Spanish breast milk samples used as a reference. We have also identified certain trace elements added to formulae which interact with selenium according to type and protein matrix of infant formula. Selenium concentration was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) with a hydride generator. The selenium concentrations in human milk and infant formula determined in this study are similar to those found by other researchers in different countries. Daily intake of studied formulae was estimated according to recommended doses from manufacturers. Theoretical intake of lactating infants has been studied in relation to the Recommended Dietary Allowance (RDA: 10 μg Se/day) and the specific recommendations for infant formula nutrient contents (10 – 35 μg/L) set by Expert Panel of Life Sciences Research Office (LSRO) of the American Society for Nutritional Sciences. According to our results, on an overall view, infants fed on the studied infant formulae have an intake between the basal and normative requirements. This might be considered to provide an adequate selenium intake. However, several formulae included in this research could provide an intake of selenium that does not reach the RDA for the first month of neonate life

Exploring the impact of atmospheric forcing and basal drag on the Antarctic Ice Sheet under Last Glacial Maximum conditions

Little is known about the distribution of ice in the Antarctic Ice Sheet (AIS) during the Last Glacial Maximum (LGM). Whereas marine and terrestrial geological data indicate that the grounded ice advanced to a position close to the continental-shelf break, the total ice volume is unclear. Glacial boundary conditions are potentially important sources of uncertainty, in particular basal friction and climatic boundary conditions. Basal friction exerts a strong control on the large-scale dynamics of the ice sheet and thus affects its size and is not well constrained. Glacial climatic boundary conditions determine the net accumulation and ice temperature and are also poorly known. Here we explore the effect of the uncertainty in both features on the total simulated ice storage of the AIS at the LGM. For this purpose we use a hybrid ice sheet shelf model that is forced with different basal drag choices and glacial background climatic conditions obtained from the LGM ensemble climate simulations of the third phase of the Paleoclimate Modelling Intercomparison Project (PMIP3). Overall, we find that the spread in the simulated ice volume for the tested basal drag parameterizations is about the same range as for the different general circulation model (GCM) forcings (4 to 6 m sea level equivalent). For a wide range of plausible basal friction configurations, the simulated ice dynamics vary widely but all simulations produce fully extended ice sheets towards the continental-shelf break. More dynamically active ice sheets correspond to lower ice volumes, while they remain consistent with the available constraints on ice extent. Thus, this work points to the possibility of an AIS with very active ice streams during the LGM. In addition, we find that the surface boundary temperature field plays a crucial role in determining the ice extent through its effect on viscosity. For ice sheets of a similar extent and comparable dynamics, we find that the precipitation field determines the total AIS volume. However, precipitation is highly uncertain. Climatic fields simulated by climate models show more precipitation in coastal regions than a spatially uniform anomaly, which can lead to larger ice volumes. Our results strongly support using these paleoclimatic fields to simulate and study the LGM and potentially other time periods like the last interglacial. However, their accuracy must be assessed as well, as differences between climate model forcing lead to a large spread in the simulated ice volume and extension

Time-scale synchronisation of oscillatory responses can lead to non-monotonous R-tipping

Rate-induced tipping (R-tipping) describes the fact that, for multistable dynamic systems, an abrupt transition can take place not only because of the forcing magnitude, but also because of the forcing rate. In the present work, we demonstrate through the case study of a piecewise-linear oscillator (PLO), that increasing the rate of forcing can make the system tip in some cases but might also prevent it from tipping in others. This counterintuitive effect is further called non-monotonous R-tipping (NMRT) and has already been observed in recent studies. We show that, in the present case, the reason for NMRT is the peak synchronisation of oscillatory responses operating on different time scales. We further illustrate that NMRT can be observed even in the presence of additive white noise of intermediate amplitude. Finally, NMRT is also observed on a van-der-Pol oscillator with an unstable limit cycle, suggesting that this effect is not limited to systems with a discontinuous right-hand side such as the PLO. This insight might be highly valuable, as the current research on tipping elements is shifting from an equilibrium to a dynamic perspective while using models of increasing complexity, in which NMRT might be observed but hard to understand

Niveles de concentración de aluminio en fórmulas infantiles

Los altos contenidos de aluminio encontrados en las fórmulas infantiles con mayor grado de procesamiento han llevado a las organizaciones pediátricas a solicitar una evaluación de estos niveles, especialmente los preparados para lactantes pretérmino. Los objetivos de este estudio son: valorar los contenidos de aluminio en los diferentes tipos de fórmula infantil comercializados en España; determinar los factores condicionantes de su preparación por parte de las diferentes casas comerciales; y, aportar un nivel máximo de aluminio recomendable para las fórmulas infantiles. La metodología empleada ha seguido un escrupuloso protocolo para evitar cualquier contaminación metálica durante el proceso de toma y tratamiento de la muestra. La digestión de las muestras se ha llevado a cabo con ácido nítrico subboiling en un sistema cerrado de microondas y bombas de digestión de teflón de alta presión. Los valores de concentración de aluminio se han determinado por espectrofotometría de absorción atómica con atomización electrotérmica. Los contenidos de aluminio obtenidos presentan una amplia variabilidad dependiendo del tipo de fórmula analizado. Globalmente, las fórmulas infantiles estudiadas proporcionan unos niveles de concentración muy superiores a los hallados en la leche materna, especialmente aquellas formulaciones de alta complejidad tecnológica (fórmulas especiales, de soja y para prematuros). A la luz de los resultados obtenidos, es conveniente solicitar de las diferentes casas comerciales continuados esfuerzos para reducir el nivel de aluminio, introducir programas rutinarios de control y observar el valor guía máximo de 300 g/L, principalmente en las fórmulas para lactantes pretérmino

Ingesta dietética y requerimientos nutricionales de elementos traza en la alimentación infantil

La deficiencia de elementos traza durante el periodo neonatal tiene gran influencia en el desarrollo posterior del lactante. Las cantidades diariamente requeridas de oligoelementos son mínimas, proporcionadas por la leche humana o de fórmula, única fuente nutricional durante la etapa de lactancia exclusiva. Los requerimientos de elementos traza son específicos para cada individuo. Considerando esta amplia variación interindividual, las recomendaciones dietéticas deben establecerse de una forma bastante amplia para cubrir las necesidades de la mayoría de la población. Por razones de ética, existen algunos datos que no pueden ser obtenidos de los lactantes en buen estado de salud sino por extrapolación de otros estudios, con todas las limitaciones inherentes a dicha deducción. La leche humana sirve de referencia en cuanto a los valores de elementos traza contenidos. En este estudio se revisan los valores de ingesta dietética diaria de elementos traza esenciales (Fe, Zn, Cu, Mn y Se) y potencialmente tóxicos (Al, Pb y Cd) proporcionada por la leche materna y las fórmulas infantiles, comparándolos con los valores de ingesta recomendados por organismos competentes. A pesar de los innumerables esfuerzos realizados por numerosos investigadores, permanecen existiendo discrepancias y desconocimiento en algunos aspectos relevantes de algunos elementos traza esenciales, manifestándose la gran necesidad de nuevos estudios relevantes con objeto de cubrir las necesidades nutricionales de elementos traza de todos los lactantes

Obtaining of repair lime renders with microencapsulated phase change materials: optimization of the composition, application, mechanical and microstructural studies

Different batches of repair lime rendering mortars were designed by mixing microencapsulated Phase Change Materials (PCMs) and other additives. The final aim of these renders is to improve the thermal efficiency of the envelope of the Built Heritage, while allowing the practitioners to apply a render with positive final performance. The combinations of the PCMs in different weight percentages, a superplasticiser (to increase the fluidity of the render keeping constant the mixing water), an adhesion improver and a pozzolanic additive were studied. The adhesion of these renders onto bricks and limestone specimens and the shrinkage and cracking of the mortars were studied in detail. X-ray diffraction technique was used to study the composition and evolution of the carbonation process. Compressive strength measurements were studied in hardened specimens. In addition, the porous structure of the rendering mortars was studied by mercury intrusion porosimetry to assess the effect of the PCMs' addition. Samples underwent accelerated climatic ageing to study their durability and the preservation of the thermal efficiency. Results have shown that these thermally enhanced mortars are feasible materia Is for real-life application in the context of architectural heritage restoration and conservation

Enhancement of latent heat storage capacity of lime rendering mortars

Microencapsulated Phase Change Materials (PCMs) were included in air lime rendering mortars in order to improve the thermal comfort of the inhabitants and the energy efficiency of buildings of the Architectural Heritage under the premises of mínimum intervention and maximum compatibility. Three different PCMs were tested and directly added during the mixing process to fresh air lime mortars in three different percentages: 5, 10 and 20 wt. %. Some chemical additives were also incorporated to improve the final performance of the renders: a starch derivative as an adhesion booster; metakaolin as pozzolanic addition to shorten the setting time and to increase the final strength; anda polycarboxylated ether as a superplasticizer to adjust the fluidity of the fresh renders avoiding an excess of mixing water. The specific heat Cp, the enthalpy ti.H ascribed to the phase change and the melting temperature of the PCMs were determined by Differential Scanning Calorimetry (DSC). The capacity of the renders to store/release heat was demonstrated at a laboratory scale. The favourable results proved the effect of these PCMs with respect to the thermal performance of these rendering mortars, offering a promising way of enhancement of the thermal efficiency of building materia Is of the Cultural Heritage

Contenidos de selenio en fórmulas infantiles y estimación de la ingesta dietética de lactantes en España

Los lactantes representan el grupo poblacional de mayor riesgo de padecer la deficiencia nutricional de selenio, considerándose un microconstituyente básico en la alimentación infantil. Su esencialidad viene determinada por el hecho de que su ingestión por debajo de las recomendaciones se traduce en una clara sintomatología de déficit. Este estudio determina los valores de concentración de selenio en los diferentes tipos de fórmulas infantiles comercializadas en España, incluyendo preparados para lactantes en polvo como líquidas, tanto fórmulas lácteas como a base de aislado de soja. La metodología empleada ha seguido un escrupuloso protocolo para evitar cualquier contaminación metálica durante el proceso de toma y tratamiento de la muestra. La digestión de las muestras se ha llevado a cabo con ácido nítrico subboiling en un sistema cerrado de microondas y bombas de digestión de teflón de alta presión. Los valores de concentración de selenio se ha determinado por espectrometría de emisión atómica con plasma acoplado por inducción y generador de hidruros. Los resultados obtenidos presentan, en términos generales, una amplia variabilidad dependiente de la fracción proteica contenida y son similares a los encontrados por otros autores en fórmulas europeas, asiáticas y americanas. Se expresan los niveles de concentración considerando su estado de agregación, comparativamente con los valores proporcionados por las casas comerciales. Se ha calculado el porcentaje de satisfacción de la RDA de selenio en relación con la estimación realizada de la ingesta dietética teórica proporcionada por las fórmulas infantiles. En general, las fórmulas infantiles investigadas cumplen las recomendaciones especificadas por los organismos pediátricos internacionales y la legislación europea, aunque algunas de ellas (formulas para toda la lactancia, adaptadas de inicio, especiales 3 sin lactosa y soja) proporcionan un aporte de selenio que no alcanza la RDA durante los primeros meses de vida del lactante, ocasionando un riesgo para la salud del neonato. A la luz de los conocimientos actuales, parece oportuno recomendar la suplementación de las fórmulas infantiles con selenio, considerando la forma química utilizada mediante estudios de especiación química

Ingestión de aluminio en lactantes alimentados con fórmulas infantiles

Las fórmulas infantiles comerciales deber proporcionar una alternativa eficaz a la leche humana, aportando una fuente nutricional segura y adecuada a las necesidades del lactante. La posibilidad de que el aluminio pueda ocasionar problemas de toxicidad justifica el objeto principal de este estudio: la comparación de la ingesta proporcionada con las fórmulas infantiles investigadas y la ingesta semanal tolerable provisional (ISTP) establecidas por el Comité Mixto FAO/OMS de expertos en Aditivos Alimentarios. Asimismo resulta interesante valorar el aporte de aluminio a la dieta del lactante a través del agua utilizada en la reconstitución de los biberones, dado que según la legislación vigente, se pueden aportar contenidos similares a los suministrados por las fórmulas infantiles. Los niveles de concentración de aluminio se han analizado mediante espectrofotometría de absorción atómica con cámara de grafito, empleándose escrupulosos protocolos de toma y tratamiento de la muestra para evitar la contaminación metálica. Las fórmulas para toda la lactancia, las adaptadas de inicio y continuación proporcionan las menores ingestas de aluminio (4 % de la ISTP), seguidas de las formulas especiales (11 - 12 %), siendo las fórmulas de soja las que aportan una mayor ingesta (15 %). Las fórmulas para prematuros presentan una ingesta del 8 - 10 %, muy lejos de los valores aportados por la leche humana de madres españolas (0,1 %) y del límite superior del valor de referencia bibliográfico de leche humana (1,3 %). El contenido de aluminio en el agua de reconstitución no constituye un gran riesgo potencial para la salud de los lactantes, aunque es necesario considerar la variabilidad en el agua potable dependiendo del medio geoquímico