Dietary Patterns and Fitness Level in Mexican Teenagers.

BACKGROUND: Nowadays, the term "physical fitness" has evolved from sports performance to health status, and it has been considered a strong predictor of cardiovascular disease. In this sense, test batteries have been developed to evaluate physical fitness such as the ALPHA-FIT battery. On the other hand, the analysis of dietary patterns has emerged as an alternative method to study the relationship between diet and chronic noncommunicable diseases. However, the association between dietary patterns and the physical fitness level has not been evaluated in both adults and adolescents. This association is most important in adolescents due to the fact that establishing healthy dietary behaviors and a favorable nutritional profile in early stages of life prevents various chronic-degenerative diseases. OBJECTIVE: To analyze the association between dietary patterns and the level of fitness in Mexican teenagers. METHODS: We analyzed the relationship between dietary patterns and the fitness level of 42 teenage students in Toluca, Mexico. Students were weighed and measured, and their food intake was recorded for 2 weekdays and one weekend day. Dietary patterns were obtained by factorial analysis. The ALPHA-FIT battery was used to measure the fitness level. RESULTS: Fifty percent of the students were found to have a low fitness level (62.1% men; 37.9% women). There was no association (X2 = 0.83) between the dietary patterns "high in fat and sugar," "high in protein", and "low in fat and protein" and the level of physical condition in teens. CONCLUSIONS: In this study, all of teenagers with a very low level of fitness obtained a high dietary pattern in protein; however, 40% with a high level of physical condition resulted in the same pattern; that is why we did not find a relationship between the fitness level and the patterns investigated in this study.

Overweight or Obesity, Gender, and Age Influence on High School Students of the City of Toluca's Physical Fitness.

MATERIAL AND METHOD: This is a prospective, cross-sectional, and correlational study with a probabilistic sampling in which 150 teenagers from three different high schools from the city of Toluca, Mexico, aged 15-17, were assessed. OBJECTIVE: To determine if weight, age, and gender have an influence on physical fitness evaluated with the EUROFIT and ALPHA-FITNESS batteries. RESULTS: Women have a higher overweight and obesity rate than men (3 : 1). Adolescents who have normal weight have regular physical fitness (74.9%). When comparing genders we found that men have a higher mean than women in the tests, except for skinfold thickness and waist circumference. Age was only correlated with the plate tapping test (p = 0.001). There are significant differences in the standing broad jump test and the Course-Navette of the EUROFIT and ALPHA-FITNESS batteries (p = 0.000). CONCLUSIONS: It is likely that regular physical activity, and not normal weight, helps generate healthy physical fitness. Male subjects had a higher mean than women, reporting a better physical fitness and more frequent physical activity.

El B-hidroxi-B-metilbutirato (HMB) como suplemento nutricional (I): metabolismo y toxicidad / B-Hidroxy-B-Methylbutyrate as a dietary supplement (I); metabolism and toxicity

Introducción: El β-hidroxi-β-metilbutirato (HMB) es un metabolito de la leucina producido a partir del ácido α-cetoisocaproico. El HMB se utiliza como suplemento nutricional en el deporte desde 1997, atribuyéndosele una disminución de la proteólisis muscular. En los últimos años, se han descrito efectos positivos del HMB en diversas patologías, lo cual aumenta su probable utilidad para la mejora de la salud. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se abordan el metabolismo y la posible toxicidad del HMB. Resultados: Diversos estudios relacionan al HMB con el metabolismo del colesterol en el músculo esquelético, probablemente reduciendo la proteólisis, a través del 3-hidroxi-3-metilglutaril-coenzima A, que se transforma a mevalonato, actuando como precursor en la síntesis de colesterol. Sin embargo, el HMB podría transformarse en beta-hidroxi-butirato a través del metabolismo del acetoacetato, por medio de la beta-hidroxibutirato dehidrogenasa. Por otra parte, la forma química más habitual en los suplementos nutricionales es la sal de calcio de HMB y la dosis más utilizada, de 3 g de HMB/día. Los estudios realizados en humanos y en animales muestran que no existen efectos adversos por el consumo de HMB. Conclusiones: Los efectos metabólicos y la ausencia de toxicidad del HMB lo hacen adecuado para su uso como suplemento nutricional (AU)

Introduction: β-hydroxy-β-methylbutyrate (HMB) is a leucine metabolite produced from α-ketoisocaproic acid. HMB supplementation has been used as a dietary supplement in sports since 1997, with the aim of decreasing muscle proteolysis. In recent years, positive effects have been reported in different pathologies, which suggests potential health benefits. Aims: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. Methods: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. Results were divided into two parts; this article presents the results about both HMB metabolism and possible toxicity. Results: Studies show that HMB is related to cholesterol metabolism in skeletal muscle, which could reduce proteolysis, through hydroxy-methyl-glutaryl-coenzyme A and mevalonate as a precursor in the synthesis of cholesterol. However, HMB could also be transformed from acetoacetate to beta-hydroxybutyrate by beta-hydrozybutyrate dehydrogenase. The calcium salt of HMB is the most used chemical form in dietary supplements, being the most common dose 3 g of HMB/day. Studies in humans and animals provide evidence that there are no adverse effects associated with HMB supplementation. Conclusion: Metabolic effects and lack of toxicity of HMB make it an adequate compound to be used as a dietary supplement (AU)

El B-hidroxi-B-metilbutirato (HMB) como suplemento nutricional (II): mecanismos de acción moleculares y celulares / B-hydroxy-B-metilbutirato as a dietary supplement (II): celland molecular mechanism of action

Introducción: En los últimos años el β-hidroxi-β-metilbutirato (HMB) ha sido foco de diversas investigaciones que le atribuyen un efecto sobre la disminución de la proteólisis muscular y un incremento de la masa muscular. Por tanto, se han realizado estudios centrados en los mecanismos celulares y moleculares responsables de dichos efectos. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se presentan los resultados referentes a los mecanismos de acción del HMB. Resultados: No existen suficientes datos que apoyen que la ingesta de HMB incremente la síntesis de colesterol en el músculo. Es posible que existan efectos positivos en el metabolismo muscular a través de la vía mTOR y del sistema ubiquitin-proteasoma, aunque no se conoce su mecanismo de acción. Probablemente, el HMB eleva los niveles sanguíneos de βhidroxibutirato y esto podría explicar sus principales efectos sobre la disminución de la proteólisis muscular. Conclusiones: De acuerdo a nuestros resultados, la posibilidad de justificar la acción del HMB a través de la vía del beta-hidroxibutirato abre una interesante línea de investigación para futuros estudios (AU)

Introduction: In recent years, several investigations have related β-hydroxy-β-methylbutyrate (HMB) to a reduced muscle proteolysis and to an increase in muscle mass. Therefore, a number of studies focused on the cellular and molecular mechanisms regulating these effects have been carried out. Aims: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. Methods: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. Results were divided into two parts; this article presents aspects referring to HMB mechanisms of action. Results: There is insufficient evidence that HMB intake increases muscle cholesterol synthesis. It probably has positive effects on muscle metabolism through both the mTOR and ubiquitin-proteasome pathways, although the mechanism of action is unknown. HMB may increase blood levels of β-hydroxybutyrate and this couldexplain the main effects of HMB on muscle proteolysis. Conclusion: According to these results, the possibility of justifying the action of HMB through the beta-hydroxybutyrate pathway opens an interesting line of research for future studies (AU)

[ß-hydroxy-ß-methylbutyrate as a dietary supplement (I): metabolism and toxicity]. / El ß-hidroxi-ß-metilbutirato (HMB) como suplemento nutricional (I): metabolismo y toxicidad.

INTRODUCTION: -hydroxy--methylbutyrate (HMB) is a leucine metabolite produced from -ketoisocaproic acid. HMB supplementation has been used as a dietary supplement in sports since 1997, with the aim of decreasing muscle proteolysis. In recent years, positive effects have been reported in different pathologies, which suggests potential health benefits. AIMS: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. METHODS: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. RESULTS were divided into two parts; this article presents the results about both HMB metabolism and possible toxicity. RESULTS: Studies show that HMB is related to cholesterol metabolism in skeletal muscle, which could reduce proteolysis, through hydroxy-methyl-glutaryl-coenzyme A and mevalonate as a precursor in the synthesis of cholesterol. However, HMB could also be transformed from acetoacetate to beta-hydroxybutyrate by beta-hydrozybutyrate dehydrogenase. The calcium salt of HMB is the most used chemical form in dietary supplements, being the most common dose 3 g of HMB/day. Studies in humans and animals provide evidence that there are no adverse effects associated with HMB supplementation. CONCLUSION: Metabolic effects and lack of toxicity of HMB make it an adequate compound to be used as a dietary supplement.

Introducción: El -hidroxi--metilbutirato (HMB) es un metabolito de la leucina producido a partir del ácido -cetoisocaproico. El HMB se utiliza como suplemento nutricional en el deporte desde 1997, atribuyéndosele una disminución de la proteólisis muscular. En los últimos años, se han descrito efectos positivos del HMB en diversas patologías, lo cual aumenta su probable utilidad para la mejora de la salud. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se abordan el metabolismo y la posible toxicidad del HMB. Resultados: Diversos estudios relacionan al HMB con el metabolismo del colesterol en el músculo esquelético, probablemente reduciendo la proteólisis, a través del 3-hidroxi-3-metilglutaril-coenzima A, que se transforma a mevalonato, actuando como precursor en la síntesis de colesterol. Sin embargo, el HMB podría transformarse en beta-hidroxi-butirato a través del metabolismo del acetoacetato, por medio de la beta-hidroxibutirato dehidrogenasa. Por otra parte, la forma química más habitual en los suplementos nutricionales es la sal de calcio de HMB y la dosis más utilizada, de 3 g de HMB/día. Los estudios realizados en humanos y en animales muestran que no existen efectos adversos por el consumo de HMB. Conclusiones: Los efectos metabólicos y la ausencia de toxicidad del HMB lo hacen adecuado para su uso como suplemento nutricional.

[ß-hydroxy-ß-methylbutyrate as a dietary supplement (II): cell and molecular mechanism of action]. / El ß-hidroxi-ß-metilbutirato (HMB) como suplemento nutricional (II): mecanismos de acción moleculares y celulares.

INTRODUCTION: In recent years, several investigations have related -hydroxy--methylbutyrate (HMB) to a reduced muscle proteolysis and to an increase in muscle mass. Therefore, a number of studies focused on the cellular and molecular mechanisms regulating these effects have been carried out. AIMS: The objectives of this review are: to know both HMB metabolism and toxicity, and to identify HMB cellular and molecular mechanisms of action when used as a dietary supplement. METHODS: A search was performed in the Web of Science, Pubmed and SportDiscus data bases. RESULTS were divided into two parts; this article presents aspects referring to HMB mechanisms of action. RESULTS: There is insufficient evidence that HMB intake increases muscle cholesterol synthesis. It probably has positive effects on muscle metabolism through both the mTOR and ubiquitin-proteasome pathways, although the mechanism of action is unknown. HMB may increase blood levels of -hydroxybutyrate and this could explain the main effects of HMB on muscle proteolysis. CONCLUSION: According to these results, the possibility of justifying the action of HMB through the beta-hydroxybutyrate pathway opens an interesting line of research for future studies.

Introducción: En los últimos años el -hidroxi--metilbutirato (HMB) ha sido foco de diversas investigaciones que le atribuyen un efecto sobre la disminución de la proteólisis muscular y un incremento de la masa muscular. Por tanto, se han realizado estudios centrados en los mecanismos celulares y moleculares responsables de dichos efectos. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB, así como su absorción y excreción; estudiar la posible toxicidad del HMB; e identificar los mecanismos celulares y moleculares de acción del HMB cuando se utiliza como suplemento nutricional. Métodos: Se utilizaron las bases de datos Web of Science, Pubmed y SportDiscus para realizar la búsqueda de artículos. Los resultados se dividieron en dos partes; en este artículo se presentan los resultados referentes a los mecanismos de acción del HMB. Resultados: No existen suficientes datos que apoyen que la ingesta de HMB incremente la síntesis de colesterol en el músculo. Es posible que existan efectos positivos en el metabolismo muscular a través de la vía mTOR y del sistema ubiquitin-proteasoma, aunque no se conoce su mecanismo de acción. Probablemente, el HMB eleva los niveles sanguíneos de hidroxibutirato y esto podría explicar sus principales efectos sobre la disminución de la proteólisis muscular. Conclusiones: De acuerdo a nuestros resultados, la posibilidad de justificar la acción del HMB a través de la vía del beta-hidroxibutirato abre una interesante línea de investigación para futuros estudios.

Effects of creatine supplementation in taekwondo practitioners.

INTRODUCTION: Taekwondo (TKD) is a combat sport, which has also been proposed as a fitness program, with a strong anaerobic component. Creatine (Cr) supplementation is used to improve both anaerobic exercise performance and body composition. Therefore, Cr supplementation could be beneficial in TKD. AIMS: To determine the effect of Cr supplementation (50 mg/kg body wt) on body composition, anaerobic power and blood chemistry in young male TKD practitioners. METHODS: Ten male TKD practitioners (age [20 ± 2 yr], height [1.69 ± 0.06 m], and mass [67 ± 9.8 kg]) participated in a placebo-controlled, double blind, crossover study. Body composition (DEXA), anaerobic power (Wingate Test), blood lactate and blood chemistry were measured before and after supplementation. Differences between data before and after supplementation were calculated for each treatment (Cr and Placebo) and were compared using the Wilcoxon signed-rank test. RESULTS: Fat mass (kg) decreased after placebo (Mdn [IqR] = -0.75 [-1.44 to 0.03]) and increased following Cr intake (0.17 [-0.77 to 1.13] kg) (Z = 2.191, p < 0.028, r = 0.49). Serum triglyceride concentration (mg/mL) increased after Cr (45.00 [-7.50 to 75.00]) and decrease with placebo (-7.00 [-10.75 to 12.00]) (Z = 2.090, p < 0.037, r = 0.47). No changes were found in others parameters. CONCLUSION: Cr supplementation may increase fat mass and serum triglycerides concentration in young male TKD practitioners without improvement in anaerobic power. Cr supplementation appears to be safe, but athletes should be careful when they want to loss fat.

Introducción: El Taekwondo (TKD) es un arte marcial, que ha sido propuesto también en programas de actividad física, con un fuerte componente anaeróbico. La suplementación con creatina (Cr), utilizada para mejorar el rendimiento deportivo y la composición corporal, puede ser beneficiosa en TKD. Objetivos: Determinar el efecto de la suplementación de Cr sobre la composición corporal, potencia anaeróbica y bioquímica sanguínea en practicantes jóvenes de TKD. Métodos: Diez practicantes varones de TKD (edad [20 ± 2 AÑOs], estatura [1,69 ± 0,06 m], peso [67,0 ± 9,8 kg]) participaron en un ensayo aleatorizado cruzado (grupo control + placebo). Se evaluaron (pre-post suplementación) la composición corporal (DEXA), la potencia anaeróbica (Test de Wingate), el lactato y la bioquímica sanguínea. Se calculó la diferencia entre los valores pre y post ingestión para ambos tratamientos (Cr y placebo) y se compararon las diferencias usando la prueba de signos y rangos de Wilcoxon. Resultados: La masa grasa (kg) disminuyó después del placebo (Mdn [IqR] = -0,75 [-1,44 a 0,03]) mientras que con Cr se elevó significativamente (0,17 [-0,77 a 1,13] kg) (Z = 2,191, p < 0,028, r = 0,49). La concentración sanguínea de triglicéridos (mg/mL) aumentó con Cr (45,00 [- 7,50 a 75,00]) y disminuyó con Placebo (-7,00 [-10,75 a 12,00]) (Z = 2,090, p < 0,037, r = 0,47). No hubo cambios significativos en otros parámetros. Conclusiones: La suplementación con creatina puede incrementar la masa grasa y la concentración sanguínea de triglicéridos en jóvenes practicantes de TKD, sin mejorar la potencia anaerobia. La suplementación parece ser segura, pero es necesario ser cuidadosos cuando se busca disminuir el peso corporal.

Effects of creatine supplementation in taekwondo practitioners / Efectos de la suplementación con creatina en practicantes de taekwondo

Introduction: Taekwondo (TKD) is a combat sport, which has also been proposed as a fitness program, with a strong anaerobic component. Creatine (Cr) supplementation is used to improve both anaerobic exercise performance and body composition. Therefore, Cr supplementation could be beneficial in TKD. Aims: To determine the effect of Cr supplementation (50 mg/kg body wt) on body composition, anaerobic power and blood chemistry in young male TKD practitioners. Methods: Ten male TKD practitioners (age [20 ± 2 yr], height [1.69 ± 0.06 m], and mass [67 ± 9.8 kg]) participated in a placebo-controlled, double blind, crossover study. Body composition (DEXA), anaerobic power (Wingate Test), blood lactate and blood chemistry were measured before and after supplementation. Differences between data before and after supplementation were calculated for each treatment (Cr and Placebo) and were compared using the Wilcoxon signed-rank test. Results: Fat mass (kg) decreased after placebo (Mdn [IqR] = -0.75 [-1.44 to 0.03]) and increased following Cr intake (0.17 [-0.77 to 1.13] kg) (Z = 2.191, p < 0.028, r = 0.49). Serum triglyceride concentration (mg/mL) increased after Cr (45.00 [-7.50 to 75.00]) and decrease with placebo (-7.00 [-10.75 to 12.00]) (Z = 2.090, p < 0.037, r = 0.47). No changes were found in others parameters. Conclusion: Cr supplementation may increase fat mass and serum triglycerides concentration in young male TKD practitioners without improvement in anaerobic power. Cr supplementation appears to be safe, but athletes should be careful when they want to loss fat (AU)

Introducción: El Taekwondo (TKD) es un arte marcial, que ha sido propuesto también en programas de actividad física, con un fuerte componente anaeróbico. La suplementación con creatina (Cr), utilizada para mejorar el rendimiento deportivo y la composición corporal, puede ser beneficiosa en TKD. Objetivos: Determinar el efecto de la suplementación de Cr sobre la composición corporal, potencia anaeróbica y bioquímica sanguínea en practicantes jóvenes de TKD. Métodos: Diez practicantes varones de TKD (edad [20 ± 2 años], estatura [1,69 ± 0,06 m], peso [67,0 ± 9,8 kg]) participaron en un ensayo aleatorizado cruzado (grupo control + placebo). Se evaluaron (pre-post suplementación) la composición corporal (DEXA), la potencia anaeróbica (Test de Wingate), el lactato y la bioquímica sanguínea. Se calculó la diferencia entre los valores pre y post ingestión para ambos tratamientos (Cr y placebo) y se compararon las diferencias usando la prueba de signos y rangos de Wilcoxon. Resultados: La masa grasa (kg) disminuyó después del placebo (Mdn [IqR] = -0,75 [-1,44 a 0,03]) mientras que con Cr se elevó significativamente (0,17 [-0,77 a 1,13] kg) (Z = 2,191, p < 0,028, r = 0,49). La concentración sanguínea de triglicéridos (mg/mL) aumentó con Cr (45,00 [7,50 a 75,00]) y disminuyó con Placebo (-7,00 [-10,75 a 12,00]) (Z = 2,090, p < 0,037, r = 0,47). No hubo cambios significativos en otros parámetros. Conclusiones: La suplementación con creatina puede incrementar la masa grasa y la concentración sanguínea de triglicéridos en jóvenes practicantes de TKD, sin mejorar la potencia anaerobia. La suplementación parece ser segura, pero es necesario ser cuidadosos cuando se busca disminuir el peso corporal (AU)