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Pleins d’estrogènes dans les suppléments?

22/08/2014 | Etudes sur les hormones et Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge et Etudes sur les boosters sexuels et la sexualité

 

Estrogenic endocrine disruptors present in sports supplements. A risk assessment for human health
Food Chemistry Volume 159, 15 September 2014, Pages 157–165     Monika Plotan

• Estrogenic activity is quantified in sports supplements and an exposure and risk assessment performed.
• 17β-Estradiol equivalent activity levels were higher than the ADI in 26% of exposure assessment samples.
• 17β-Estradiol equivalent activity levels were higher in 66% of exposure assessment samples than levels present in the typical diet.
• The predicted hormonal impact of greatest concern is for young boys and postmenopausal women.
• Consumers of sport supplements may be exposed to high levels of estrogenic endocrine disruptors.

Sports supplements are becoming a regular dietary addition for consumers who view such products as a means of improving their health and performance. Previously estrogenic endocrine disruptors (EDs) were detected in 80% of 116 sports supplements investigated by biological in vitro reporter gene assays (RGAs). The aim of this study was to quantify the hormonal activity in 50 of these sports supplement samples using a validated estrogen RGA and perform an exposure and risk assessment for human health.

Results showed that 17β-estradiol equivalent levels were higher than those reported as being present in the typical human omnivore diet in 33 of the sports supplements and higher than the acceptable daily intake (ADI) in 13 of these products. The highest activity samples presented a potential to influence the human daily exposure to 17β-estradiol like activity in various risk groups with a predicted hormonal impact of greatest concern in young boys and postmenopausal women.

In conclusion, consumers of sports supplements may be exposed to high levels of estrogenic EDs.

La muscu augmente la rétention d’eau intracellulaire

22/08/2014 | Etudes sur les hormones et Etudes Musculation et Etudes Perte de poids

 

Belle mécanique qui se grippe au régime

Resistance training promotes increase in intracellular hydration in men and women
Alex S. Ribeiro     European Journal of Sport Science Volume 14, Issue 6, 2014 pages 578-585

The main purpose of the present study was to investigate the effect of 16 weeks of resistance training (RT) on body water in men and women. Thirty men (22.7 ± 4.4 years, 68.4 ± 9.0 kg and 174.5 ± 6.6 cm) and 34 women (22.7 ± 4.1 years, 58.8 ± 11.9 kg and 162.6 ± 6.2 cm) underwent progressive RT for 16 weeks (2 phases, 8 weeks each), 3 times per week, that consisted of 10–12 whole body exercises with 3 sets of 8–12 repetitions maximum. Total body water, TBW (intracellular water, ICW and extracellular water, ECW compartments) and skeletal muscle mass (SMM) were assessed using a spectral bioelectrical impedance device (Xitron 4200 Bioimpedance Spectrum Analyzer).
TBW, ICW compartment and SMM increased significantly (P

< 0.05) over time in men (+7.5%, +8.2% and +4.2%

, respectively)
and                                                                             women (+7.6%, +11.0% +3.9%, respectively), with no sex by time interaction (P > 0.05).
We conclude that progressive RT promotes an increase in body water, principally by intracellular content; however, the hydration status is not influenced by sex.

Nouvelles fonctions pour la myostatine

20/08/2014 | Etudes sur les hormones

 

On retrouve encore l’antagonisme grosseur du muscle/endurance

Myostatin is a key mediator between energy metabolism and endurance capacity of skeletal muscle
Etienne Mouisel
American Journal of Physiology - Regulatory, Integrative and Comparative Physiology Published 15 August 2014 Vol. 307 no. R444-R454

Myostatin (Mstn) participates in the regulation of skeletal muscle size and has emerged as a regulator of muscle metabolism. Here, we hypothesized that lack of myostatin profoundly depresses oxidative phosphorylation-dependent muscle function. Toward this end, we explored Mstn−/− mice as a model for the constitutive absence of myostatin and AAV-mediated overexpression of myostatin propeptide as a model of myostatin blockade in adult wild-type mice. We show that muscles from Mstn−/− mice, although larger and stronger, fatigue extremely rapidly. Myostatin deficiency shifts muscle from aerobic toward anaerobic energy metabolism, as evidenced by decreased mitochondrial respiration, reduced expression of PPAR transcriptional regulators, increased enolase activity, and exercise-induced lactic acidosis. As a consequence, constitutively reduced myostatin signaling diminishes exercise capacity, while the hypermuscular state of Mstn−/− mice increases oxygen consumption and the energy cost of running. We wondered whether these results are the mere consequence of the congenital fiber-type switch toward a glycolytic phenotype of constitutive Mstn−/− mice. Hence, we overexpressed myostatin propeptide in adult mice, which did not affect fiber-type distribution, while nonetheless causing increased muscle fatigability, diminished exercise capacity, and decreased Pparb/d and Pgc1a expression. In conclusion, our results suggest that myostatin endows skeletal muscle with high oxidative capacity and low fatigability, thus regulating the delicate balance between muscle mass, muscle force, energy metabolism, and endurance capacity.

LES SPORTIFS TRANSPIRENT PLUS, PLUS FACILEMENT

20/08/2014 | Etudes sur les hormones

 

Comparison of peripheral sudomotor sensitivity to acetylcholine in endurance and non-endurance trained male subjects
    Young Oh Shin   Muscle & Nerve Volume 50, Issue 3,  pages 407–412, September 2014

We investigated the effect of endurance and non-endurance training on peripheral sudomotor sensitivity.

Methods: The quantitative sudomotor axon reflex test (QSART) was performed.

Results: Endurance-trained subjects (ET, long-distance runners) had a significantly shorter onset time of sweating, greater sweat volume, increased density of activated sweat glands and sweat gland output per single activated gland, greater volume of transepidermal water loss, and higher skin temperature compared with those in the other 2 groups [non–endurance-trained group (NET), sedentary control group (CT)].

NET subjects (baseball players) had a tendency to increase in these variables; thus, some values were greater than control subjects.

Conclusions: These results suggest that endurance training much more effectively modifies sudomotor sensitivity than non-endurance training.

Comment l’effort physique combat-il la dépression?

17/08/2014 | Etudes Anti-âge

 

Changes in markers of brain serotonin activity in response to chronic exercise in senior men
Michel O. Melancon   Physiologie appliquée, nutrition et métabolisme, 10.1139/apnm-2014-0092

Le vieillissement réduit le niveau de transmission cérébrale de la sérotonine, pouvant contribuer à vulnérabiliser l’aîné à développer la dépression. La recherche a montré que l’exercice aérobie entraîne une hausse d’activité sérotonergique centrale accompagnée d’une élévation de la disponibilité sanguine du tryptophane (« TRP », précurseur de la sérotonine) pour le cerveau. Toutefois, l’effet de l’exercice chronique sur l’activité sérotonergique de l’aîné demeure inconnu.

Seize hommes âgés (64 ± 3 ans) ont effectué 1 h d’exercice (67–70 % pic de consommation d’oxygène) avant et après 4 mois d’entraînement aérobie. Les principales mesures étaient les suivantes: condition cardiorespiratoire, composition corporelle, acides aminés ramifiés (« BCAA »), TRP, prolactine, lactate et acides gras (FFA). Les changements sanguins en TRP-libre/BCAA et prolactine ont servi de substituts pour la disponibilité du TRP et l’activité sérotonergique. L’entraînement a réduit le poids corporel (P < 0.05) et a augmenté le seuil ventilatoire 2 (P < 0.01). Malgré que le ratio d’acides aminés post-entraînement fût inchangé au repos, l’effort aigu a augmenté la disponibilité du TRP indépendamment de l’entraînement (P < 0.001). Toutefois, la disponibilité du TRP a plafonné durant l’effort à des valeurs plus basses après l’entraînement (P < 0.05); une réponse similaire est survenue au niveau du lactate, prolactine et FFA.

Ces données montrent que l’exercice aérobie cause une hausse transitoire consistante de la disponibilité du TRP sanguin au cerveau chez l’aîné; l’élévation était indépendante de l’entraînement physique, bien que moins prononcée après l’entraînement. Ces données supportent l’hypothèse que des hausses répétées d’activité sérotonergique cérébrale sous-tendent l’effet antidépresseur de l’exercice chronique chez l’aîné.

La cacao est bon pour la peau

13/08/2014 | Etudes Compléments alimentaires et Etudes Anti-âge

 

Au lieu de prendre une protéine avec du faux chocolat, autant en prendre une nature et rajouter un cacao de bonne qualité

Cocoa Bioactive Compounds: Significance and Potential for the Maintenance of Skin Health
Nutrients 2014, 6(8), 3202-3213;  Giovanni Scapagnini

Cocoa has a rich history in human use. Skin is prone to the development of several diseases, and the mechanisms in the pathogenesis of aged skin are still poorly understood. However, a growing body of evidence from clinical and bench research has begun to provide scientific validation for the use of cocoa-derived phytochemicals as an effective approach for skin protection. Although the specific molecular and cellular mechanisms of the beneficial actions of cocoa phytochemicals remain to be elucidated, this review will provide an overview of the current literature emphasizing potential cytoprotective pathways modulated by cocoa and its polyphenolic components. Moreover, we will summarize in vivo studies showing that bioactive compounds of cocoa may have a positive impact on skin health.

Connaissez-vous le muscle Sternalis?

12/08/2014 | Anatomie

 

Sternalis muscle, what every anatomist and clinician should know
Michael Snosek       Clinical Anatomy Volume 27, Issue 6, pages 866–884, September 2014

The sternalis muscle is a well documented but rare muscular variation of the anterior thoracic wall. It lies between the superficial fascia and the pectoral fascia and is found in about 8% of the population.
It presents in several morphological variants both unilaterally and bilaterally and has no apparent physiological function.

There is still much disagreement about its nerve supply and embryological origin. With the advent of medical imaging and thoracic surgery the clinical importance of this muscle has been re-emphasized. It has been implicated in misdiagnosis of breast masses on routine mammograms owing to its parasternal location and relative unfamiliarity among radiologists. When undetected before any thoracic surgery, it has the potential to interfere with and prolong such procedures. When present and detected preoperatively it can be used as a muscular flap in reconstructive surgeries of the breast and neck. This article will present the sternalis muscle with special emphasis on its morphology, homology, and clinical significance

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