News dalla Ricerca del 14 Settembre 2010

Pubblicato: settembre 14, 2010 in general

Bad News sul Consumo di Fruttosio!!!!!

Eliminare la Frutta? NOOOOOOOOOO!!!!

Eliminare il fruttosio puro? SIIIIIIIIII!!!!!!!!!!!!!

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Am J Physiol Endocrinol Metab. 2010 Sep 7. [Epub ahead of print]

Fructose: A highly lipogenic nutrient implicated in insulin resistance, hepatic steatosis and metabolic syndrome.

Dekker MJ, Su Q, Baker C, Rutledge AC, Adeli K.

1The Hospital for Sick Children.

Abstract
As dietary exposure to fructose has increased over the past 40 years, there is growing concern that high fructose consumption in humans may be in part responsible for the rising incidence of obesity worldwide. Obesity is associated with a host of metabolic challenges, collectively termed the metabolic syndrome. Fructose is a highly lipogenic sugar that has profound metabolic effects in the liver and has been associated with many of the components of the metabolic syndrome (insulin resistance, elevated waist circumference, dyslipidemia and hypertension). Recent evidence has also uncovered effects of fructose in other tissues, including adipose tissue, the brain and the gastrointestinal system, that may provide new insight into the metabolic consequences of high fructose diets. Fructose feeding has now been shown to alter gene expression patterns (such as peroxisome proliferators-activated receptor gamma coactivator-1alpha/beta in the liver), alter satiety factors in the brain, increase inflammation, reactive oxygen species and portal endotoxin concentrations via Toll-like receptors, and induce leptin resistance. This review highlights recent findings in fructose feeding studies in both human and animal models with a focus on the molecular and biochemical mechanisms that underlie the development of insulin resistance, hepatic steatosis, and the metabolic syndrome.

PMID: 20823452 [PubMed – as supplied by publis

her]

J Appl Physiol. 2010 Sep 9. [Epub ahead of print]

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MOTOR UNIT BEHAVIOR DURING SUBMAXIMAL CONTRACTIONS FOLLOWING SIX WEEKS OF AN ENDURANCE AND A STRENGTH TRAINING PROGRAM.

Vila-Chã C, Falla D, Farina D.

1Aalborg University.

Abstract
The study investigated changes in motor output and motor unit behavior following 6 weeks of either strength or endurance training programs commonly used in conditioning and rehabilitation. Twenty-eight sedentary healthy men (age, mean ± SD, 26.1 ± 3.9 yrs) were randomly assigned to strength training (ST) (n = 9), endurance training (ET) (n = 10) or a control group (CT) (n = 8). Maximum voluntary contraction (MVC), time to task failure (isometric contraction at 30% MVC), and rate of force development (RFD) of the quadriceps, were measured before (week 0), during (week 3), and after a training program of 6 weeks. In each experimental session, surface and intramuscular EMG signals were recorded from the vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles during isometric knee extension at 10% and 30% MVC. After 6 weeks of training, MVC and RFD increased in the ST group (17.5±7.5 % and 33.3±15.9 %, respectively; P < 0.05) whereas time to task failure was prolonged in the ET group (29.7±13.4 %; P < 0.05). The surface EMG amplitude at 30% MVC force increased with training in both groups but the training-induced changes in motor unit discharge rates differed between groups. After endurance training, the motor unit discharge rate at 30% MVC decreased from 11.3 ±1.3 pulses per second (pps) to 10.1 ± 1.1 pps (P < 0.05) in the vasti muscles, whereas after strength training it increased from 11.4 ± 1.2 pps to 12.7 ± 1.3 pps (P < 0.05). Finally, motor unit conduction velocity during the contractions at 30% MVC increased for both the ST and ET groups, but only after 6 weeks of training (P < 0.05). In conclusion, these strength and endurance training programs elicit opposite adjustments in motor unit discharge rates but similar changes in muscle fiber conduction velocity.

PMID: 20829500 [PubMed – as supplied by publisher]

Nutr Res Pract. 2010 Aug;4(4):259-69. Epub 2010 Aug 31.

Combatti l’infiammazione silente in PALESTRA!!!!

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Effects of resistance training on the inflammatory response.

Calle MC, Fernandez ML.

Department of Nutritional Sciences, University of Connecticut, 3624 Horsebarn Road Ext, Storrs, CT 06269, USA.

Abstract
Resistance training (RT) is associated with reduced risk of low grade inflammation related diseases, such as cardiovascular disease and type 2 diabetes. The majority of the data studying cytokines and exercise comes from endurance exercise. In contrast, evidence establishing a relationship between RT and inflammation is more limited. This review focuses on the cytokine responses both following an acute bout, and after chronic RT. In addition, the effect of RT on low grade systemic inflammation such as individuals at risk for type 2 diabetes is reviewed. Cytokines are secreted proteins that influence the survival, proliferation, and differentiation of immune cells and other organ systems. Cytokines function as intracellular signals and almost all cells in the body either secrete them or have cytokine receptors. Thus, understanding cytokine role in a specific physiological situation such as a bout of RT can be exceedingly complex. The overall effect of long term RT appears to ameliorate inflammation, but the specific effects on the inflammatory cytokine, tumor necrosis factor alpha are not clear, requiring further research. Furthermore, it is critical to differentiate between chronically and acute Interleukin-6 levels and its sources. The intensity of the RT and the characteristics of the training protocol may exert singular cytokine responses and as a result different adaptations to exercise. More research is needed in the area of RT in healthy populations, specifically sorting out gender and age RT acute responses. More importantly, studies are needed in obese individuals who are at high risk of developing low grade systemic inflammatory related diseases. Assuring adherence to the RT program is essential to get the benefits after overcoming the first acute RT responses. Hence RT could be an effective way to prevent, and delay low grade systemic inflammatory related diseases.

PMID: 20827340 [PubMed – in process]Free PMC Article

Curr Sports Med Rep. 2010 September/October;9(5):307-313.

An Overview of Strength Training Injuries: Acute and Chronic.

Lavallee ME, Balam T.

1Indiana University School of Medicine, South Bend, IN; USA Weightlifting, Sports Medicine Committee, Colorado Springs, CO; International Weightlifting Federation, Masters Division, Budapest, Hungary; South Bend Sports Medicine Fellowship Program, South Bend, IN; Indiana University South Bend, South Bend, IN; Holy Cross College, Notre Dame, IN; University of Notre Dame, Notre Dame, IN; 2Family Medicine, Memorial Family Medicine Residency Program, South Bend, IN; 3Memorial Sports Medicine Institute, South Bend, IN.

Abstract
This article introduces the history of strength training, explains the many different styles of strength training, and discusses common injuries specific to each style. Strength training is broken down into five disciplines: basic strength or resistance training, bodybuilding, power lifting, style-dependant strength sports (e.g., strongman competitions, Highland games, field events such as shot put, discus, hammer throw, and javelin), and Olympic-style weightlifting. Each style has its own principal injuries, both acute and chronic, related to the individual technique. Acute injuries should be further categorized as emergent or nonemergent. Specific age-related populations (i.e., the very young and the aging athlete) carry additional considerations.

PMID: 20827099 [PubMed – as supplied by publisher]

J Med Food. 2010 Sep 9. [Epub ahead of print]

 

Aumenta le tue capacita’ di endurance con l’acido linoeico coniugato (se ti comporti come un topolino)….

 

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Dietary Conjugated Linoleic Acid Increases Endurance Capacity of Mice During Treadmill Exercise.

Kim JH, Park HG, Pan JH, Kim SH, Yoon HG, Bae GS, Lee H, Eom SH, Kim YJ.

1 Department of Food and Biotechnology, Korea University , Chungnam, Republic of Korea.

Abstract
Abstract This study was designed to evaluate the effect of dietary conjugated linoleic acid (CLA) on endurance exercise and availability of metabolic substrates in mice. Four-week-old male BALB/c mice were randomized to a control group (normal diet) and a CLA group (normal diet?+?1% CLA). Each animal group received its respective diet for 10 weeks and was subjected to forced running on a treadmill system to estimate their maximum endurance capacity at the end of the experiment. All mice were immediately sacrificed after prolonged exercise, and the major metabolic substrates were measured in serum and liver. The body weights of mice in the CLA group were lower than those of the control group after the 10 weeks. The maximum running time in CLA-fed mice was significantly longer, by 26%, compared to that of the control mice. Dietary CLA decreased the serum concentrations of triglycerides, nonesterified fatty acids, and urea nitrogen and significantly reduced the consumption of liver glycogen. The present study demonstrated that dietary CLA enhances the endurance capacity of mice by increasing fat utilization and reducing the consumption of stored liver glycogen as substrates for energy metabolism

Physiol Behav. 2010 Sep 3.

Mangia piu’ proteine e stimola il lipoburning!!!

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Protein intake induced increase in exercise stimulated fat oxidation during stable body weight.

Soenen S, Plasqui G, Smeets AJ, Westerterp-Plantenga MS.

Abstract
BACKGROUND: Protein-rich weight-loss diets spare fat-free mass at the cost of fat mass. The objective was to examine if there is a change in stimulated fat oxidation related to protein intake during stable body weight.
METHODS: Subjects’ (BMI 22±2kg/m(2), age 25±8y) maximal fat oxidation (Fat(max)) was assessed during a graded bicycle test, before and after a 3-month dietary-intervention of 2MJ/d supplements exchanged with 2MJ/d of habitual energy intake. The parallel design consisted of protein-rich supplements in the protein group and an isocaloric combination of carbohydrate and fat supplements in the control group. Daily protein intake was determined according to 24-hour urine nitrogen. Body composition was measured according to a 4-compartment model by a combination of underwater-weighing technique, deuterium-dilution technique and whole-body dual-energy X-ray absorptiometry (DXA).Results: Subjects were weight stable and did not change their physical activity. The protein group (n=12) increased protein intake (11±14g, P<0.05) and had significantly higher daily protein intake vs. control (n=4) (80±21 vs.59±11g, P<0.05). Fat(max) increased significantly in the protein group (0.08±0.08g/min, P<0.01). Fat-free mass increased independent of change in body weight (P<0.01), and fat mass and fat percentage decreased (P<0.05). Change in Fat(max) was a function of change in protein intake (r=0.623, P<0.05), and not of changes in body composition or VO(2)max.
CONCLUSION: Increased stimulated fat oxidation was related to increased protein intake.

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