If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
http://www.eurekalert.org/pub_releas...-cos022504.php
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect (February 25, 2004) - Bethesda, MD – A visit to the meat counter at any supermarket is proof positive that a good number of Americans are avoiding carbohydrates and consuming high levels of protein and fat, in accordance with the Atkins diet. This carbohydrate-free, fat- and protein- rich diet is for those seeking immediate weight loss, which means most of us. But what do others, such as weight lifters and callisthenic enthusiasts, do about carbohydrates? Their goal is muscle preservation and strengthening, but for years, different theories have been offered about the effectiveness of carbohydrates in maintaining an appropriate muscle protein balance. A new study may lead to a truce in the debate at the nation's gymnasiums, and those dedicated to resistance training may finally have an answer as to whether carbohydrates have a positive role in muscle development. Resistance exercise -- also called strength training -- increases muscle strength and mass, bone strength, and the body's metabolism. The different methods for resistance training include free weights, weight machines, calisthenics and resistance tubing. When using free weights, dumbbells, and bars stacked with weight plates, you are responsible for both lifting the weight and determining and controlling your body position through the range of motion. The body's net muscle protein balance (i.e., the difference between muscle protein synthesis and protein breakdown) generally remains negative in the recovery period after resistance exercise in the absence of nutrient intake, i.e., the muscle's protein is breaking down complex chemical compounds to simpler ones. However, it has been demonstrated that infusion or ingestion of amino acids after resistance exercise stimulates muscle protein synthesis. Furthermore, as little as six grams of essential amino acids (EAA) alone effectively stimulates net protein synthesis after a strenuous resistance exercise session. The body's response to the six grams of EAA does not appear to differ when 35 grams of carbohydrates are added. This reflects the uncertainty of the independent effects of carbohydrates on muscle protein metabolism after resistance exercise. Additionally, it is unclear how carbohydrate intake causes changes of net protein balance between synthesis and breakdown and how it relates to changes in plasma insulin concentration. Interpretation of the response of muscle protein to insulin is complicated by the fact that a systemic increase in insulin concentration causes a fall in plasma amino acid concentrations, and this reduced amino acid availability could potentially counteract a direct effect of insulin on synthesis. A past study found that the normal postexercise increase in muscle protein breakdown was slowed by insulin, thus improving net muscle protein balance. However, whereas local infusion of insulin may effectively isolate the effect of insulin per se, the response may differ from when insulin release is stimulated by ingestion of carbohydrates. Accordingly, a new study set out to investigate the independent effect of carbohydrate intake on muscle protein net balance during recovery from resistance exercise. The authors of "Effect Of Carbohydrate Intake on Net Muscle Protein Synthesis During Recovery from Resistance Exercise," are Elisabet Børsheim, Melanie G. Cree, Kevin D. Tipton, Tabatha A. Elliott, Asle Aarsland, and Robert R. Wolfe, all from the Department of Surgery, Metabolism Unit, Shriners Hospitals for Children-Galveston, University of Texas Medical Branch, Galveston, TX. Their findings appeared in the February 2004 edition of the Journal of Applied Physiology. The journal is one of 14 peer-reviewed scientific journals published each month by the American Physiological Society (www.APS.org). Sixteen recreationally active and healthy subjects took part in the study. At least one week before an experiment, subjects were familiarized with the exercise protocol, and their one repetition maximum, a maximum weight possible with a leg extension, was determined. The subjects were assigned to one of two groups: carbohydrate group (CHO; n = 8) or placebo group (n = 8). Subjects were instructed not to exercise for at least 48 hours before an experiment, not to use tobacco or alcohol during the 24 h before an experiment, and not to make any changes in their dietary habits. The two groups of eight subjects performed a resistance exercise bout (10 sets of eight repetitions of leg presses at 80 percent of one repetition maximum) before they rested in bed for four hours. One group (CHO) received a drink consisting of 100 grams of carbohydrates one hour after exercise; the placebo group received a noncaloric placebo drink. Leg amino acid metabolism was determined by infusion of 2H5- or 13C6-labeled phenylalanine, sampling from femoral artery and vein, and muscle biopsies from vastus lateralis, the lateral head of quadriceps muscle of anterior (extensor) compartment of thigh. Key findings of the study included: Plasma glucose concentration was significantly increased in the carbohydrate group until 210 min after intake of drink. Plasma concentration of insulin reflected the changes in glucose concentration. The drink intake did not affect arterial insulin concentration in the placebo group, whereas arterial insulin increased by several times after the drink in the CHO group. Arterial phenylalanine (a common amino acid in proteins) concentration did not change after intake of drink in the placebo group but decreased and stabilized in the CHO group. Net muscle protein balance between synthesis and breakdown did not change in the placebo group but improved in the CHO group during the second and third hour after the drink. The improved net balance in the CHO group was due primarily to a progressive decrease in muscle protein breakdown. Conclusions: This study is the first to compare net muscle protein balance (protein synthesis minus breakdown) after carbohydrate ingestion with control after exercise. The principal finding was that intake of 100 grams of carbohydrates after resistance exercise improved muscle net protein balance. The findings from this research demonstrate that carbohydrates intake alone can improve net protein balance between synthesis and breakdown. In this work, the gradual improvement in net muscle protein balance after carbohydrate intake was due principally to a progressive reduction in breakdown. However, the improvement was small compared with previous findings after intake of amino acids or amino acids and carbohydrates. The researchers conclude that intake of carbohydrates alone after resistance exercise will modestly improve the anabolic effect of exercise. However, amino acid intake is necessary for a maximal response, one desired by most participating in resistance exercise programs. Source: February 2004 edition of the Journal of Applied Physiology. The journal is one of 14 peer-reviewed scientific journals published each month by the American Physiological Society (www.APS.org). The American Physiological Society (APS) was founded in 1887 to foster basic and applied science, much of it relating to human health. The Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals every year. |
#2
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, butnot enough for the desired effect
Diarmid Logan wrote:
http://www.eurekalert.org/pub_releas...-cos022504.php Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect This comes to you from the Dept. of No **** we Knew this 10 years ago Sherlock. The only confusion comes in that carbs don't appear to affect protein SYNTHESIS (an increase in insulin prmiarily affecting protein breakdown, decreasing it). HIgh AA concentrations stimulate protein synthesis. Cobmining the two (high insulin + high AA) gives better results, something that's been known for years. But thanks for being on the cutting edge of about 1995 or so. Lyle |
#3
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
Lyle McDonald wrote:
Diarmid Logan wrote: http://www.eurekalert.org/pub_releas...-cos022504.php Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect This comes to you from the Dept. of No **** we Knew this 10 years ago Sherlock. The only confusion comes in that carbs don't appear to affect protein SYNTHESIS (an increase in insulin prmiarily affecting protein breakdown, decreasing it). HIgh AA concentrations stimulate protein synthesis. Cobmining the two (high insulin + high AA) gives better results, something that's been known for years. But thanks for being on the cutting edge of about 1995 or so. Lyle That is a harsh reply to an informative article, one that you yourself learned something from. Perhaps you could give us a reference to the 1995 studies you refer to above, so that we may place the current work in better perspective. Mark |
#4
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
"Lyle McDonald" wrote in message ... Diarmid Logan wrote: http://www.eurekalert.org/pub_releas...-cos022504.php Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect This comes to you from the Dept. of No **** we Knew this 10 years ago Sherlock. The only confusion comes in that carbs don't appear to affect protein SYNTHESIS (an increase in insulin prmiarily affecting protein breakdown, decreasing it). HIgh AA concentrations stimulate protein synthesis. Cobmining the two (high insulin + high AA) gives better results, something that's been known for years. But thanks for being on the cutting edge of about 1995 or so. Lyle A nasty SOB are you not? I am delighted not to be one of your friends. MikeV |
#5
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
"Mike V" whined A nasty SOB are you not? I am delighted not to be one of your friends. MikeV This may help you understand this newsgroup. http://home.comcast.net/~mfw/ Pay particular attention to # 19, # 23, # 24 and the closing remarks. |
#6
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
"Lee Michaels" wrote in message news:z87%b.409140$na.796892@attbi_s04... "Mike V" whined A nasty SOB are you not? I am delighted not to be one of your friends. MikeV This may help you understand this newsgroup. http://home.comcast.net/~mfw/ Pay particular attention to # 19, # 23, # 24 and the closing remarks. stick your stupid charter up your ass, you dumb ****** |
#7
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, butnot enough for the desired effect
Mike V wrote:
"Lyle McDonald" wrote in message ... Diarmid Logan wrote: http://www.eurekalert.org/pub_releas...-cos022504.php Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect This comes to you from the Dept. of No **** we Knew this 10 years ago Sherlock. The only confusion comes in that carbs don't appear to affect protein SYNTHESIS (an increase in insulin prmiarily affecting protein breakdown, decreasing it). HIgh AA concentrations stimulate protein synthesis. Cobmining the two (high insulin + high AA) gives better results, something that's been known for years. But thanks for being on the cutting edge of about 1995 or so. Lyle A nasty SOB are you not? I am delighted not to be one of your friends. MikeV Wow, that really hurts, man. But I guess this is why you hang out with the other pussies on mfm. Lyle Sob |
#8
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
"David" wrote in message ... "Lee Michaels" wrote in message news:z87%b.409140$na.796892@attbi_s04... "Mike V" whined A nasty SOB are you not? I am delighted not to be one of your friends. MikeV This may help you understand this newsgroup. http://home.comcast.net/~mfw/ Pay particular attention to # 19, # 23, # 24 and the closing remarks. stick your stupid charter up your ass, you dumb ****** That's the MFW we all know and love. |
#9
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
"Mark Gebhard" wrote in message ... "David" wrote in message ... "Lee Michaels" wrote in message news:z87%b.409140$na.796892@attbi_s04... "Mike V" whined A nasty SOB are you not? I am delighted not to be one of your friends. MikeV This may help you understand this newsgroup. http://home.comcast.net/~mfw/ Pay particular attention to # 19, # 23, # 24 and the closing remarks. stick your stupid charter up your ass, you dumb ****** That's the MFW we all know and love. David Forgot Why (an appropriate screen name) is obviously an individual who has issues with clear communication and practical knowledge. |
#10
|
|||
|
|||
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect
"Lee Michaels" wrote in message news:YO7%b.16960$AL.337350@attbi_s03... "Mark Gebhard" wrote in message ... "David" wrote in message ... "Lee Michaels" wrote in message news:z87%b.409140$na.796892@attbi_s04... "Mike V" whined A nasty SOB are you not? I am delighted not to be one of your friends. MikeV This may help you understand this newsgroup. http://home.comcast.net/~mfw/ Pay particular attention to # 19, # 23, # 24 and the closing remarks. stick your stupid charter up your ass, you dumb ****** That's the MFW we all know and love. David Forgot Why (an appropriate screen name) is obviously an individual who has issues with clear communication and practical knowledge. sure, and you are obviously a genius |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Article: The TRUTH About Low Carb Diets by Keith Klein | Steve | General Discussion | 24 | June 7th, 2004 09:05 PM |
Diet Linked To Non-Hodgkin's Lymphoma | pearl | General Discussion | 166 | April 11th, 2004 10:29 AM |
Carbohydrates offer some help in muscle protein synthesis, but not enough for the desired effect | Diarmid Logan | General Discussion | 152 | February 29th, 2004 08:53 PM |
Effect of High-Carbohydrate Feeding on Triglyceride and Saturated Fatty Acid Synthesis | Charles Henkel | Low Carbohydrate Diets | 1 | February 16th, 2004 01:24 AM |
Low carb diets | General Discussion | 249 | January 8th, 2004 11:15 PM |