Efectos de la proteína whey, leucina y entrenamiento de fuerza en la composición corporal / Effects of whey protein, leucine and resistance training on body composition

INTRODUCCIÓN: Los deportistas y las personas activas que entrenan la fuerza para lograr un aumento de su masa muscular tienen requerimientos calóricos y proteicos aumentados, por esta razón emplean diversas estrategias como la suplementación con proteína whey aislada y aminoácidos aislados como la leucina después del entrenamiento sustentados en la premisa de que promueven el incremento en la síntesis de proteínas musculares, y por ende un aumento de la masa magra. OBJETIVO: Comparar cambios de la composición corporal aplicando el método de Absorciometría Dual de Rayos X (DEXA) en personas físicamente activas expuestas a un programa de entrenamiento de la fuerza con la suplementación de proteína whey aislada y/o leucina durante 12 semanas. METODOLOGÍA: estudio aleatorizado prospectivo longitudinal en un grupo de 10 varones físicamente activos, los cuales fueron asignados al azar en 3 grupos de suplementación con proteína whey aislada, leucina o la mezcla de ambas bajo el mismo protocolo de entrenamiento de la fuerza. Se evaluó la composición corporal en 3 momentos: semana 0, semana 6 y semana 12 de la intervención. RESULTADOS: En las condiciones evaluadas no se observaron cambios estadísticamente significativos de las variables de composición corporal y fuerza en los diferentes protocolos de suplementación: leucina, proteína whey aislada con leucina y proteína whey aislada. CONCLUSIONES: Se observaron resultados superiores de la masa magra y la fuerza en el grupo de la suplementación de proteína whey aislada con leucina con respecto a los demás grupos, cabe aclarar que por el tamaño de muestra no alcanzó a ser estadísticamente significativo.

INTRODUCTION: Athletes and active people who work hard to increase their muscle mass have increased caloric and protein requirements. For this reason, they use different strategies such as whey protein isolate supplementation and/or branched-chain amino acids after sustained training on the premise that they promote an increase in muscle protein synthesis, and therefore an increase in lean mass. OBJECTIVE: To compare body composition changes in physically active people exposed to a strength training program withwhey protein isolate and/or leucine supplementation for 12 weeks. METHODS: Longitudinal prospective randomized study in a group of 10 physically active males, which were randomly assigned to 3 supplementation groups with whey protein isolate, leucine, or a mixture of both, under the same strength training protocol. Body composition was evaluated in 3 moments: week 0, week 6 and week 12 of the intervention. RESULTS: In the evaluated conditions, no statistically significant changes were observed in the variables of body composition and strength based on the different supplementation protocols: Leucine, protein with leucine and protein. CONCLUSIONS: Compared with the other groups, higher results were observed in lean mass and strength in group using the whey protein isolate supplementation with leucine. It should be noted that due to the size of the sample, the difference was not statistically significant.

Study of serum vitamin D2 and calcium in young and middle aged healthy male smokers in rural tertiary care center

Background: Smoking is an essential determinant of various diseases. The study is aimed to understand the influence of smoking on serum vitamin D2/D3 levels and serum calcium levels in healthy young/middle-aged men.Methods: Prospective observational study was done among young and middle-aged healthy male smokers in a rural territory care center. Two hundred patients were studied and analyzed, who fulfill the inclusion and exclusion criteria.Results: The prevalence of vitamin D deficiency (25(OH)D <20 ng/ml) was 50.3%. Only 8.8% of the participants had vitamin D sufficiency (25 hydroxyvitamin D ?30 ng/ml). There is a strong correlation between 25(OH)D and smoking in the participants (p<0.001). 25 hydroxyvitamin D level was lower by approximately 4.3 ng/ml (p<0.001) in a smoker compared to a non-smoker among the total participants, this value increased to 9.2 ng/ml in the 40-50y subgroup (p=0.003). A multinomial logistic regression model demonstrated that a young smoker (20-29y) had a 58% increased likelihood of having vitamin D deficiency compared to a non-smoker of the same age group (p=0.041). Irrespective of age and chronicity of smoking, there was a significantly increased level of serum calcium and significant vitamin D2/D3 deficiency in smokers.Conclusion: A high prevalence of vitamin D deficiency was identified in young and middle-aged male smokers, which is not likely to be explained by other confounding lifestyle factors. The depression of the vitamin D-PTH system seen among smokers may represent another potential mechanism for the harmful effects of smoking on the skeleton

Association of measures of central fat accumulation indices with body fat distribution and metabolic, hormonal, and inflammatory parameters in women with polycystic ovary syndrome

ABSTRACT Objective To investigate the associations among visceral adiposity index (VAI), lipid accumulation product (LAP), body fat percentage (%), and android/gynoid ratio (A/G ratio) in women with polycystic ovary syndrome (PCOS) and verify if the parameters representative of visceral obesity correlate with and exhibit the same frequency as body composition variables; anthropometric indices; and metabolic, hormonal, and inflammatory parameters. Subjects and methods This was a cross-sectional study that included 94 women with PCOS. Hormonal, metabolic, and inflammatory parameters were analyzed in all women. Free androgen index (FAI) and homeostasis model assessment (HOMA-IR), as well as LAP, VAI, and anthropometric indices, were calculated. The regions of interest (ROIs) in body composition and body composition indices were evaluated using a dual X-ray absorptiometry (DXA). Overall, 32 variables were selected as markers of body fat distribution. Results Among the 32 markers evaluated, 29 correlated with LAP, whereas 25 correlated with VAI, 19 with body fat (%), and 30 with A/G ratio. Additionally, some markers correlated with the four adiposity indices evaluated: ROIs, except for total mass and leg fat (%); body composition (body mass index, waist circumference, and hip circumference) indices; fasting insulin; and C-reactive protein. Conclusion LAP and VAI may be sensitive measures for screening and preventing metabolic syndrome and insulin resistance in PCOS, with LAP being more sensitive than VAI, and the A/G ratio may be more sensitive than body fat percentage.

Bone mineral density and mandibular osteoporotic alterations in type 2 diabetes / Densidade mineral óssea e alterações osteoporóticas na mandíbula em pacientes diabéticos do tipo 2

Objective: To assess the influence of type 2 diabetes on bone mineral density in a group of type 2 diabetic patients, in comparison with non-diabetic patients. Additionally, to evaluate the correlation between mandibular cortical index and bone mineral density. Material and Methods: 48 patients (24 diabetics and 24 non-diabetics) referred for femur and spine densitometry and panoramic radiograph examination were included in this study. Patients were diagnosed based on densitometric results of the total femur and total spine. All panoramic radiomorphometric measurements were performed by 3 observers. Differences in T and Z-scores between both groups were evaluated with Mann-Whitney test and non-parametric correlations between mandibular cortical index and T/Z-scores were carried out with Spearman's test. Results: Median T and Z-scores for total femur and total spine presented no statistical significant difference between diabetic and nondiabetic patients. In addition, only diabetics total femur and non-diabetics total spine T-scores were significantly correlated with mandibular cortical index. Conclusion: The present results suggest that type 2 diabetic patients have similar Z and T-scores in femur and spine when compared to non-diabetic patients. Mandibular cortical index, assessed on panoramic radiographs is inversely correlated with femur densitometry results in diabetics and spine bone mineral density in nondiabetic patients. (AU)

Objetivo: avaliar a influência do diabetes tipo 2 na densidade mineral óssea em um grupo de pacientes diabéticos do tipo 2, em comparação com pacientes não diabéticos. Adicionalmente, analisar a correlação entre o índice cortical mandibular e a densidade mineral óssea. Material e Métodos: 48 pacientes (24 diabéticos e 24 não diabéticos) que realizaram densitometria óssea de fêmur e coluna vertebral e exame radiográfico panorâmico foram incluídos neste estudo. Os pacientes foram diagnosticados com base nos resultados densitométricos do fêmur total e da coluna total. Por meio das radiografias panorâmicas, 3 observadores avaliaram o índice da cortical mandibular. Diferenças em T e Z scores entre os dois grupos foram avaliadas com o teste de MannWhitney e as correlações não paramétricas entre o índice cortical mandibular e os scores da densitometria foram verificadas por meio do teste de Spearman. Resultados: A mediana dos T e Z-scores para fêmur total e coluna total não apresentaram diferença estatisticamente significante entre diabéticos e não-diabéticos. Além disso, houve correlação significativa com o índice da cortical mandibular somente os T-scores de fêmur total do grupo de pacientes diabéticos e de coluna total dos paciente não-diabéticos. Conclusão: Os resultados deste estudo sugerem que pacientes diabéticos tipo 2 tem densidade mineral óssea aferida por meio de densitometria óssea do fêmur e coluna total semelhantes aos não-diabéticos. O índice cortical mandibular, avaliado em radiografias panorâmicas, foi inversamente correlacionado com os resultados da densitometria do fêmur em pacientes diabéticos e da densitometria de coluna total de pacientes não diabéticos. (AU)

Equations based on anthropometry to predict body fat measured by absorptiometry in schoolchildren and adolescents / Equações com base na antropometria para prever a gordura corporal medida por absorciometria em crianças em idade escolar e adolescentes

Abstract Objective: To develop and validate equations to estimate the percentage of body fat of children and adolescents from Mexico using anthropometric measurements. Methods: A cross-sectional study was carried out with 601 children and adolescents from Mexico aged 5-19 years. The participants were randomly divided into the following two groups: the development sample (n = 398) and the validation sample (n = 203). The validity of previously published equations (e.g., Slaughter) was also assessed. The percentage of body fat was estimated by dual-energy X-ray absorptiometry. The anthropometric measurements included height, sitting height, weight, waist and arm circumferences, skinfolds (triceps, biceps, subscapular, supra-iliac, and calf), and elbow and bitrochanteric breadth. Linear regression models were estimated with the percentage of body fat as the dependent variable and the anthropometric measurements as the independent variables. Results: Equations were created based on combinations of six to nine anthropometric variables and had coefficients of determination (r2) equal to or higher than 92.4% for boys and 85.8% for girls. In the validation sample, the developed equations had high r2 values (≥85.6% in boys and ≥78.1% in girls) in all age groups, low standard errors (SE ≤ 3.05% in boys and ≤3.52% in girls), and the intercepts were not different from the origin (p > 0.050). Using the previously published equations, the coefficients of determination were lower, and/or the intercepts were different from the origin. Conclusions: The equations developed in this study can be used to assess the percentage of body fat of Mexican schoolchildren and adolescents, as they demonstrate greater validity and lower error compared with previously published equations.

Resumo Objetivo: Desenvolver e validar equações para estimar o percentual de gordura corporal (%GC) de crianças e adolescentes do México com medidas antropométricas. Métodos: Foi feito um estudo transversal com 601 crianças e adolescentes do México cinco e 19 anos. Os participantes foram divididos aleatoriamente nos seguintes dois grupos: a amostra de desenvolvimento (n = 398) e a amostra de validação (n = 203). A validade das equações publicadas anteriormente (por exemplo, Slaughter) também foi avaliada. O %GC foi estimado por absorciometria de dupla energia de raios X (raios X de dupla energia [DXA]). As medidas antropométricas incluíram estatura, altura sentado, peso, circunferências da cintura e do braço, dobras cutâneas (tríceps, bíceps, subescapular, suprailíaca e panturrilha) e larguras do cotovelo e bitrocantérica. Os modelos de regressão linear foram estimados com o %GC, a variável dependente e as medidas antropométricas como as variáveis independentes. Resultados: As equações foram criadas com base nas combinações de seis a nove variáveis antropométricas e apresentaram coeficientes de determinação (r2) iguais ou superiores a 92,4% para meninos e 85,8% para meninas. Na amostra de validação, as equações desenvolvidas apresentaram altos valores de r2 (≥ 85,6% em meninos e ≥ 78,1% em meninas) em todos os grupos, baixo nível de erros padrão (EP ≤ 3,05% em meninos e ≤ 3,52% em meninas) e os interceptos não foram diferentes da origem (p > 0,050). Com as equações publicadas anteriormente, os coeficientes de determinação foram menores e/ou os interceptos foram diferentes da origem. Conclusões: As equações desenvolvidas neste estudo podem ser usadas para avaliar o %GC das crianças em idade escolar e adolescentes mexicanos, pois têm uma maior validade e menor erro em comparação com as equações publicadas anteriormente.

Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

OBJECTIVE: The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. MATERIALS AND METHODS: An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. RESULTS: There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 (micro)Gy and 1.81 (micro)Gy, respectively. Also, the scan center dose in the women was 5.70 (micro)Gy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. CONCLUSION: We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry.

Cross-calibration of Bone Mineral Density between Two Different Dual X-ray Absorptiometry Systems: Hologic QDR 4500-A and Lunar EXPERT-XL / 대한핵의학회잡지

PURPOSE: A cross-calibration equation is needed to compare bone mineral density measured by different dual X-ray absoptiometry systems. We performed this study to establish appropriate cross-calibration equations between two different dual X-ray absorptiometry systems. MATERIALS AND METHODS: Bone mineral density of anterior-posterior lumbar spine (L2-4 level) and femoral neck were measured in 109 women (55+/-11yr) using two different dual X-ray absorptiometry systems (Lunar EXPERT-XL) and Hologic QDR 4500-A). Bone mineral density values measured by two systems, including area, bone mass content, bone mineral density and percentile of young normals were compared and cross-calibration equations between two systems derived. RESULTS: The bone mineral density values of 109 women measured by Lunar system were 0.958+/-0.17 g/cm2 at L2-4 and 0.768+/-0.131 g/cm2 at femur neck, which were significantly higher (13+/-6% at L2-4 and 19+/-7% at femur neck, p0.05). There was a high correlation between bone mineral density values of L2-4 and femoral neck obtained with both dual X-ray absortiometry systems (r=0.96 and 0.95, respectively). Cross-calibration equations relating the bone mineral density were Lunar=1.1287xHologic-0.0027 for L2-4 and Lunar=l.1556xHologic+0.0l82 for femoral neck. CONCLUSION:: We obtained cross-calibration equations of bone mineral density between Lunar EXPERT-XL and Hologic QDR 4500-A. These equations can be useful in comparing bone mineral density obtained by different dual X-ray absorptiometry systems.