l-Arginine and Beetroot Extract Supplementation in the Prevention of Sarcopenia.

Aging is associated with a significant decline in neuromuscular function, leading to a reduction in muscle mass and strength. The aim of the present report was to evaluate the effect of supplementation with nitric oxide precursors (l-arginine and beetroot extract) in muscular function during a training period of 6 weeks in elderly men and women. The study (double-blind, placebo-controlled) involved 66 subjects randomly divided into three groups: placebo, arginine-supplemented and beetroot extract-supplemented. At the end of this period, no changes in anthropometric parameters were observed. Regarding other circulating parameters, urea levels were significantly (p < 0.05) lower in women of the beetroot-supplemented group (31.6 ± 5.9 mg/dL) compared to placebo (41.3 ± 8.5 mg/dL) after 6 weeks of training. In addition, the circulating creatine kinase activity, as an index of muscle functionality, was significantly (p < 0.05) higher in women of the arginine- (214.1 ± 162.2 mIU/L) compared to the beetroot-supplemented group (84.4 ± 36.8 mIU/L) at the end of intervention. No significant effects were noticed with l-arginine or beetroot extract supplementation regarding strength, endurance and SPPB index. Only beetroot extract supplementation improved physical fitness significantly (p < 0.05) in the sprint exercise in men after 6 weeks (2.33 ± 0.59 s) compared to the baseline (2.72 ± 0.41 s). In conclusion, beetroot seems to be more efficient during short-term training while supplementing, preserving muscle functionality in women (decreased levels of circulating creatine kinase) and with modest effects in men.

L-Citrulline Supplementation and Exercise in the Management of Sarcopenia.

Sarcopenia is a process associated to aging. Persistent inflammation and oxidative stress in muscle favour muscle wasting and decreased ability to perform physical activity. Controlled exercise can optimize blood flux and moderate the production of reactive oxygen species. Therefore, supplements that can work as a vasodilators and control oxidative stress, might be beneficial for active elders. In this context, we have tested citrulline supplementation in a group of 44 participants aged from 60-73 years that followed a physical activity program adapted to their age and capacities. Volunteers were divided in two groups: placebo (n = 22) and citrullline supplemented (n = 22). Different physical tests and blood extractions were performed at the beginning and at the end of intervention (six weeks). Strength and endurance showed a tendency to increase in the citrulline supplemented group, with no significant differences respect to placebo. However, walking speed in the citrulline supplemented group improved significantly compared to placebo. Markers of muscle damage as well as circulating levels of testosterone, cortisol and vitamin D showed no significant changes, but a tendency to improve at the end of intervention in the supplemented group compared to placebo. Additional studies are necessary to confirm the effect of citrulline supplementation in sarcopenia delay.

Restricción calórica, un método eficaz, sencillo y saludable para perder peso / Caloric restriction, an effective, simple and healthy way to lose weight

Introducción: El modelo de Restricción Calórica (RC) pretende reducir el total de calorías ingeridas por semana. Las dos formas más usuales de alcanzar el déficit calórico deseado (% RC) son reducir la ingesta cada día o establecer unos días intermitentes de ayuno o restricción severa, donde el impacto de la restricción es más importante, tiene menor repercusión sobre la pérdida de masa muscular, y está más facilitada la adherencia al modelo de dieta. Se propone trabajar sobre un modelo de RC cercana al 40% del contenido calórico ordinario, intercalando 3 días de restricción severa (600-800Kcal) por semana con los restantes de ingesta habitual, durante un periodo de 6 semanas. Contenido de la investigación: Dieciocho sujetos sanos y físicamente activos, siguieron una pauta de restricción calórica (34,3 ± 15,4%) durante 6 semanas, en las que mantuvieron su actividad física regular. Al inicio y al final del experimento se determinó la composición corporal por densitometria (DEXA) y se cuantificó la pérdida de peso y su distribución en los diferentes tejidos. También se valoraron las consecuencias de la dieta en parámetros hematológicos y bioquímicos. Conclusiones: Se consigue una pérdida de peso considerable, principalmente a expensas de la masa grasa (de predominio androide), con un menor efecto sobre la masa libre de grasar, y existe una buena tolerancia y adherencia a la pauta propuesta. Consideramos la RC como una buena opción para el ajuste de peso en deportistas (AU)

Introduction: The Calorie Restriction (CR) model aims to reduce the total calories eaten per week. The two most common ways to achieve the desired caloric deficit (% CR) are to reduce intake every day or to establish intermittent fasting or severe restriction days, where the impact of the restriction is more important, has less impact on the loss of mass muscle, and adherence to the diet model is more facilitated. It is proposed to work on a CR model close to 40% of the normal caloric content, intercalating 3 days of severe restriction (600-800Kcal) per week with the rest of habitual intake, over a period of 6 weeks. Content of the research: Eighteen healthy and physically active subjects followed a caloric restriction pattern (34.3 ± 15.4%) for 6 weeks, in which they maintained their regular physical activity. At the beginning and at the end of the experiment the body composition by densitometry was determined and the weight loss and its distribution in the different tissues were quantified. The consequences of diet were also evaluated in hematological and biochemical parameters. Conclusions: A considerable weight loss is achieved, mainly at the expense of the fat mass (predominantly android), with a lower effect on the fat free mass, and there is a good tolerance and adherence to the proposed pattern. We consider CR as a good option for weight adjustment in athletes (AU)

Changes in circulating cytokines and markers of muscle damage in elite cyclists during a multi-stage competition.

The purpose of this study was to determine the changes in the basal and post-exercise plasma markers of muscular damage, lipid peroxidation and cytokines in eight male well-trained semiprofessional cyclists, in response to a three consecutive-day cycling competition. Serum markers of oxidative and muscular damage - creatine kinase activity, lactate dehydrogenase activity, myoglobin and malondialdehyde (MDA), creatinine and nitrite levels - followed a sawtooth-type representation throughout the competition. MDA showed an accumulative pattern, evidenced in the post-race values of the third stage which were significantly higher with respect to the values of the first stage. Cortisol levels were significantly influenced by an interaction between the exercise and the stage factors, with higher values on the 4th day. Plasma cytokine levels were only determined before the first stage and post-race, after the third stage. The exercise increased TNFα, IL6, IL2 and IFNγ levels, whereas IL1ß was unchanged. In conclusion, cyclist stages induced oxidative and cellular muscle damage which is partially recovered to basal values by the next morning. Repetitive stages during the cycling competition accumulated plasma muscular damage and lipid peroxidation markers and pro-inflammatory cytokines, probably as a result of local inflammatory responses.