NUTRITIONAL INTAKE AND NUTRITIONAL STATUS IN ELITE MEXICAN TEENAGERS SOCCER PLAYERS OF DIFFERENT AGES.

INTRODUCTION: nutritional intake and status of soccer players has attracted not much research attention. Many soccer players follow an inadequate nutritional intake and have a poor nutritional status. This is relevant in youngsters soccer players, in order to improve performance and promote healthy dietary practices. AIMS: analyze anthropometric characterizes, evaluate nutritional intake and status, dietary habits and pre- and post-exercise meals in elite teenagers soccer players. METHODS: seventy-two young male soccer players (15-20 years) from four junior teams of a soccer Club from the Mexican National Soccer League were measured for height, seat height, weight, 6 skinfolds, 6 diameters and 7 circumferences, height-for-age and BMI-for-age values. Skin, adipose, muscle, bone and residual tissue masses were calculated with the Ross and Kerr equation. Resting energy expenditure and intake was also measured. Daily dietary intake was self-recorded for 4 consecutive days (excluding the match day) using a digital food-weighing scale and a food record questionnaire. Dietary analysis was performed using the NutriBase 7 Clinical software. Several biochemical values were determined. One-way analysis of variance (ANOVA) and post hoc testing was performed using t-tests with a Bonferroni correction. RESULTS: all soccer players were within the normal range values for anthropometric parameters studies, when compared with other adolescent elite soccer teams. Values of plasma glucose, urea, creatinine, uric acid, lipid profile and total proteins were within normal range for young adult population, although albumin levels were high. Moreover, 14% and 20% of soccer players presented hyperuricemia and elevated total cholesterol levels respectively. Energy expenditure and intake were within normal range for all teenager elite soccer players. However, two teams shower significant lower intakes than demands. All macronutrient intakes were within recommendations, except protein that was higher. Micronutrient intake exceeded the recommendations for general population. Soccer players had pre- and post-exercise meals with an appropriate range of carbohydrates. Food intake was mainly based on cereals, derivatives and potatoes; meat, poultry, fish, shellfish and eggs and biscuits and confectionery and poor in fruit, vegetables and milk and dairy products. CONCLUSIONS: the population of soccer players did not have optimal nutritional habits. However, their nutritional intake and status was better than in other published studies. The main problems of these teams were that they had a high protein diet and that in some teams the nutritional intake was not enough to cover the demands. Finally, nutritional intake was found to be of poor quality. Thus, we recommend nutritional education for soccer players of these teams.

Introducción: la ingesta nutricional y el estado nutricional de los futbolistas no han suscitado mucha atención. La mayoría de los futbolistas siguen una dieta inadecuada y tienen una condición nutricional pobre. Esto adquiere mayor importancia cuando se trata de jugadores jóvenes, ya que se podrían mejorar su juego y sus hábitos nutricionales. Objetivos: analizar las características antropométricas, la ingesta y el estado nutricional, los hábitos dietéticos y la alimentación antes y después del ejercicio en equipos de élite de futbolistas adolescentes. Métodos: se estudiaron a 72 jugadores masculinos de 15-20 años, pertenecientes a cuatro equipos junior de un club mejicano de la Liga de Fútbol Nacional. A los jugadores se les midió el peso, la altura, la altura sentado, seis pliegues cutáneos, seis diámetros, siete circunferencias, los valores estatura para la edad e IMC para la edad. La masa de piel, tejido adiposo, músculo, hueso y masa residual se calcularon con la ecuación de Ross y Kerr. Se midió el gasto energético y la ingesta energética diaria. Se recogió la ingesta diaria durante cuatro días (excluyendo el día del partido) y se empleó una báscula digital y un cuestionario dietético. El análisis dietético se realizó con el programa NutriBase 7 Clinical. Se midieron varios parámetros bioquímicos. Se empleó el test ANOVA y los test post hoc usados fueron el de la t´Student y el de Bonferroni. Resultados: los parámetros antropométricos de todos los futbolistas estudiados se encontraban dentro de los valores normales para futbolistas de élite adolescentes. Los valores plasmáticos de glucosa, urea, creatinina, ácido úrico, perfil lipídico y proteínas totales estaban dentro de los valores normales de la población adolescente. Sin embargo, la albúmina se encontraba elevada y el 14 y el 20% de los futbolistas presentaban niveles altos de ácido úrico y colesterol. La ingesta energética y el gasto energético eran los habituales en los futbolistas de élite adolescentes, aunque dos equipos tenían una ingesta energética inferior a sus necesidades. El consumo de micronutrientes era superior a las recomendaciones para la población normal. Los futbolistas ingerían comidas pre y post-ejercicio, con unas cantidades adecuadas de carbohidratos. Su alimentación se basaba fundamentalmente en el consumo de cereales, pastas y derivados; productos cárnicos; pescados; huevos; bollería industrial y golosinas. Además era muy pobre en frutas, verduras y productos lácteos. Conclusiones: la población de futbolistas estudiados no tuvo unos hábitos nutricionales óptimos. Sin embargo, fueron mejores que los que se vieron en otros estudios publicados. Los principales problemas nutricionales observados fueron que la dieta era elevada en proteínas, que en algunos casos era insuficiente para cubrir las demandas energéticas y que era poco variada. Así pues, se recomienda una educación nutricional para esos equipos de futbolistas.

Nutritional intake and nutritional status in elite Mexican teenagers soccer players of different ages / Ingesta nutricional y estado nutricional de jugadores de élite adolescentes, de fútbol mexicano, de diferentes edades

Introduction: nutritional intake and status of soccer players has attracted not much research attention. Many soccer players follow an inadequate nutritional intake and have a poor nutritional status. This is relevant in youngsters soccer players, in order to improve performance and promote healthy dietary practices. Aims: analyze anthropometric characterizes, evaluate nutritional intake and status, dietary habits and pre- and post-exercise meals in elite teenagers soccer players. Methods: seventy-two young male soccer players (15-20 years) from four junior teams of a soccer Club from the Mexican National Soccer League were measured for height, seat height, weight, 6 skinfolds, 6 diameters and 7 circumferences, height-for-age and BMI-for-age values. Skin, adipose, muscle, bone and residual tissue masses were calculated with the Ross and Kerr equation. Resting energy expenditure and intake was also measured. Daily dietary intake was self-recorded for 4 consecutive days (excluding the match day) using a digital food-weighing scale and a food record questionnaire. Dietary analysis was performed using the NutriBase 7 Clinical software. Several biochemical values were determined. One-way analysis of variance (ANOVA) and post hoc testing was performed using t-tests with a Bonferroni correction. Results: all soccer players were within the normal range values for anthropometric parameters studies, when compared with other adolescent elite soccer teams. Values of plasma glucose, urea, creatinine, uric acid, lipid profile and total proteins were within normal range for young adult population, although albumin levels were high. Moreover, 14% and 20% of soccer players presented hyperuricemia and elevated total cholesterol levels respectively. Energy expenditure and intake were within normal range for all teenager elite soccer players. However, two teams shower significant lower intakes than demands. All macronutrient intakes were within recommendations, except protein that was higher. Micronutrient intake exceeded the recommendations for general population. Soccer players had pre- and post-exercise meals with an appropriate range of carbohydrates. Food intake was mainly based on cereals, derivatives and potatoes; meat, poultry, fish, shellfish and eggs and biscuits and confectionery and poor in fruit, vegetables and milk and dairy products. Conclusions: the population of soccer players did not have optimal nutritional habits. However, their nutritional intake and status was better than in other published studies. The main problems of these teams were that they had a high protein diet and that in some teams the nutritional intake was not enough to cover the demands. Finally, nutritional intake was found to be of poor quality. Thus, we recommend nutritional education for soccer players of these teams (AU)

Introducción: la ingesta nutricional y el estado nutricional de los futbolistas no han suscitado mucha atención. La mayoría de los futbolistas siguen una dieta inadecuada y tienen una condición nutricional pobre. Esto adquiere mayor importancia cuando se trata de jugadores jóvenes, ya que se podrían mejorar su juego y sus hábitos nutricionales. Objetivos: analizar las características antropométricas, la ingesta y el estado nutricional, los hábitos dietéticos y la alimentación antes y después del ejercicio en equipos de élite de futbolistas adolescentes. Métodos: se estudiaron a 72 jugadores masculinos de 15-20 años, pertenecientes a cuatro equipos junior de un club mejicano de la Liga de Fútbol Nacional. A los jugadores se les midió el peso, la altura, la altura sentado, seis pliegues cutáneos, seis diámetros, siete circunferencias, los valores estatura para la edad e IMC para la edad. La masa de piel, tejido adiposo, músculo, hueso y masa residual se calcularon con la ecuación de Ross y Kerr. Se midió el gasto energético y la ingesta energética diaria. Se recogió la ingesta diaria durante cuatro días (excluyendo el día del partido) y se empleó una báscula digital y un cuestionario dietético. El análisis dietético se realizó con el programa NutriBase 7 Clinical. Se midieron varios parámetros bioquímicos. Se empleó el test ANOVA y los test post hoc usados fueron el de la t´Student y el de Bonferroni. Resultados: los parámetros antropométricos de todos los futbolistas estudiados se encontraban dentro de los valores normales para futbolistas de élite adolescentes. Los valores plasmáticos de glucosa, urea, creatinina, ácido úrico, perfil lipídico y proteínas totales estaban dentro de los valores normales de la población adolescente. Sin embargo, la albúmina se encontraba elevada y el 14 y el 20% de los futbolistas presentaban niveles altos de ácido úrico y colesterol. La ingesta energética y el gasto energético eran los habituales en los futbolistas de élite adolescentes, aunque dos equipos tenían una ingesta energética inferior a sus necesidades. El consumo de micronutrientes era superior a las recomendaciones para la población normal. Los futbolistas ingerían comidas pre y post-ejercicio, con unas cantidades adecuadas de carbohidratos. Su alimentación se basaba fundamentalmente en el consumo de cereales, pastas y derivados; productos cárnicos; pescados; huevos; bollería industrial y golosinas. Además era muy pobre en frutas, verduras y productos lácteos. Conclusiones: la población de futbolistas estudiados no tuvo unos hábitos nutricionales óptimos. Sin embargo, fueron mejores que los que se vieron en otros estudios publicados. Los principales problemas nutricionales observados fueron que la dieta era elevada en proteínas, que en algunos casos era insuficiente para cubrir las demandas energéticas y que era poco variada. Así pues, se recomienda una educación nutricional para esos equipos de futbolistas (AU)

MCT2 expression and lactate influx in anorexigenic and orexigenic neurons of the arcuate nucleus.

Hypothalamic neurons of the arcuate nucleus control food intake, releasing orexigenic and anorexigenic neuropeptides in response to changes in glucose concentration. Several studies have suggested that the glucosensing mechanism is governed by a metabolic interaction between neurons and glial cells via lactate flux through monocarboxylate transporters (MCTs). Hypothalamic glial cells (tanycytes) release lactate through MCT1 and MCT4; however, similar analyses in neuroendocrine neurons have yet to be undertaken. Using primary rat hypothalamic cell cultures and fluorimetric assays, lactate incorporation was detected. Furthermore, the expression and function of MCT2 was demonstrated in the hypothalamic neuronal cell line, GT1-7, using kinetic and inhibition assays. Moreover, MCT2 expression and localization in the Sprague Dawley rat hypothalamus was analyzed using RT-PCR, in situ hybridization and Western blot analyses. Confocal immunohistochemistry analyses revealed MCT2 localization in neuronal but not glial cells. Moreover, MCT2 was localized to ∼90% of orexigenic and ~60% of anorexigenic neurons as determined by immunolocalization analysis of AgRP and POMC with MCT2-positives neurons. Thus, MCT2 distribution coupled with lactate uptake by hypothalamic neurons suggests that hypothalamic neurons control food intake using lactate to reflect changes in glucose levels.

Glucose increases intracellular free Ca(2+) in tanycytes via ATP released through connexin 43 hemichannels.

The ventromedial hypothalamus is involved in regulating feeding and satiety behavior, and its neurons interact with specialized ependymal-glial cells, termed tanycytes. The latter express glucose-sensing proteins, including glucose transporter 2, glucokinase, and ATP-sensitive K(+) (K(ATP) ) channels, suggesting their involvement in hypothalamic glucosensing. Here, the transduction mechanism involved in the glucose-induced rise of intracellular free Ca(2+) concentration ([Ca(2+) ](i) ) in cultured ß-tanycytes was examined. Fura-2AM time-lapse fluorescence images revealed that glucose increases the intracellular Ca(2+) signal in a concentration-dependent manner. Glucose transportation, primarily via glucose transporters, and metabolism via anaerobic glycolysis increased connexin 43 (Cx43) hemichannel activity, evaluated by ethidium uptake and whole cell patch clamp recordings, through a K(ATP) channel-dependent pathway. Consequently, ATP export to the extracellular milieu was enhanced, resulting in activation of purinergic P2Y(1) receptors followed by inositol trisphosphate receptor activation and Ca(2+) release from intracellular stores. The present study identifies the mechanism by which glucose increases [Ca(2+) ](i) in tanycytes. It also establishes that Cx43 hemichannels can be rapidly activated under physiological conditions by the sequential activation of glucosensing proteins in normal tanycytes.

MCT expression and lactate influx/efflux in tanycytes involved in glia-neuron metabolic interaction.

Metabolic interaction via lactate between glial cells and neurons has been proposed as one of the mechanisms involved in hypothalamic glucosensing. We have postulated that hypothalamic glial cells, also known as tanycytes, produce lactate by glycolytic metabolism of glucose. Transfer of lactate to neighboring neurons stimulates ATP synthesis and thus contributes to their activation. Because destruction of third ventricle (III-V) tanycytes is sufficient to alter blood glucose levels and food intake in rats, it is hypothesized that tanycytes are involved in the hypothalamic glucose sensing mechanism. Here, we demonstrate the presence and function of monocarboxylate transporters (MCTs) in tanycytes. Specifically, MCT1 and MCT4 expression as well as their distribution were analyzed in Sprague Dawley rat brain, and we demonstrate that both transporters are expressed in tanycytes. Using primary tanycyte cultures, kinetic analyses and sensitivity to inhibitors were undertaken to confirm that MCT1 and MCT4 were functional for lactate influx. Additionally, physiological concentrations of glucose induced lactate efflux in cultured tanycytes, which was inhibited by classical MCT inhibitors. Because the expression of both MCT1 and MCT4 has been linked to lactate efflux, we propose that tanycytes participate in glucose sensing based on a metabolic interaction with neurons of the arcuate nucleus, which are stimulated by lactate released from MCT1 and MCT4-expressing tanycytes.