Proteinbehov för idrottsmän

[Mantus]

Ursprungligen postat av King Grub

Robert Wolfe om proteinbehov ur JAMA Vol. 299 No. 24, June 25, 2008:

http://jama.ama-assn.org/cgi/content/short/299/24/2891

Du tror inte att du kan citera relevanta delar av artikeln här? Sidan är enbart tillgänglig för prenumeranter och det verkar kosta en del att bli det.

[Ola Wallengren]

Ursprungligen postat av Mantus

Du tror inte att du kan citera relevanta delar av artikeln här? Sidan är enbart tillgänglig för prenumeranter och det verkar kosta en del att bli det.

JAMA. 2008;299(24):2891-2893.

At periodic intervals the Food and Nutrition Board of the Institute of Medicine produces a report entitled the Dietary Reference Intakes (DRI). The recent DRI report for macronutrients (energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids) was published in 2005.1 For each macronutrient, a series of values is published, along with a detailed review of all data used to derive those values. Those values for macronutrients are the estimated average requirement, the recommended dietary allowance (RDA), the tolerable upper intake level, and the adequate intake. Of these terms, the RDA is the most widely recognized and has the greatest influence on daily nutrition practices.

The RDA is defined as follows: "The recommended dietary allowance (RDA) is an estimate of the minimum daily average dietary intake level that meets the nutrient requirements of nearly all (97 to 98 percent) healthy individuals."1 In addition, the intent of the most recent DRI was to extend, where possible, beyond the concept of minimal requirement to the expression of a goal for consumption. In this case, the RDA would ideally represent an optimal intake of the nutrient, based on health outcomes such as decreased risk of heart disease. This approach was used for a number of nutrients. However, considerable confusion has resulted from the uneven application of this approach. Most notably, the RDAs for carbohydrate, fat, and protein adhere to the strict definition of the RDA (ie, the minimal amount to meet nutrient requirement, rather than an optimal level of nutrient intake).

The RDA for carbohydrate was taken to be the minimal amount required to satisfy the energy requirement of the central nervous system (120 g for adults >18 years), because the central nervous system normally relies entirely on circulating glucose as an energy substitute. It was determined that there is no particular requirement for total fat intake, and therefore there is no RDA. Minimal values for required intake of linoleic acid (between 12-17 g, depending on age and sex) and n-3 polyunsaturated fats (between 1.1-1.6 g) were provided.1 In addition, the requirement for protein for adults older than 18 years was determined to be 0.8 g of protein per kilogram body weight per day (g/kg/d).1

The RDA for protein was based on the results of all available studies that estimated the minimum protein intake necessary to avoid a progressive loss of lean body mass as reflected by nitrogen balance. The Food and Nutrition Board acknowledged the conceptual limitation of relying entirely on results from nitrogen balance studies to determine the RDA, because this method does not measure any relevant physiological end point. Furthermore, the existing data were gathered almost entirely in college-aged men and a greater nitrogen intake is likely required to maintain nitrogen balance in elderly persons.2 Regardless of whether 0.8 g/kg/d is an appropriate value for the RDA for elderly persons as well as for 18- to 50-year-old individuals, the point is that the RDA is functionally defined as the amount of protein needed to avoid a deficiency that would lead to a progressive loss of lean body mass (as reflected by negative nitrogen balance).

The minimal nature of the RDAs for carbohydrate, fat, and protein is underscored by considering the sum of the energy equivalents of the corresponding RDAs in relation to the estimated energy requirements published in the same DRI document.1 The estimated energy requirement for a 70-kg man and a 57-kg woman older than 18 years is 3067 and 2403 kcal/d, respectively.1 However, when summed together, the RDAs for carbohydrate, fat, and protein for individuals of the same weight would provide approximately 970 kcal/d for the man and 886 kcal/d for the woman. The RDAs for macronutrients thus total approximately one-third of the calories to meet the requirement for energy balance.

The DRI report clearly distinguished the RDAs for macronutrients from recommended intake in the context of a complete diet. The Acceptable Macronutrient Distribution Range (AMDR) was published in the same document1 to express recommended intakes of macronutrients as percentages of total energy intake. The AMDR accounts for the sum of macronutrient intake having to equal total energy intake, and that a diet composed only of the RDAs for protein, carbohydrate, and fat will fall well short of total energy requirements.

The AMDR is defined as "a range of intakes for a particular energy source that is associated with reduced risk of chronic diseases while providing adequate intakes of essential nutrients."1 The definition of the AMDR is more in line with the concept of optimal nutrient intake, as opposed to the minimal required intake reflected by the RDA. In the case of protein, the AMDR was cited to be between 10% and 35% of the daily energy intake.1 The AMDR for protein can be expressed in the same units as the RDA (g/kg/d) by accounting for the energy expenditure of the individual. For example, the daily energy requirement of a sedentary 19-year-old reference man (76 kg and 1.76 m tall) is estimated to be 37.8 kcal/kg/d in the section on energy requirements in the DRI.1 Ten percent of this caloric intake translates to a protein intake of 0.95 g/kg/d and 35% of energy intake translates to 3.3 g/kg/d. Thus, the RDA is below the lowest intake recommended by the AMDR when considered in the context of the overall dietary intake of macronutrients. Expressed differently, if the reference man were to consume the RDA of protein, it would constitute only 8.5% of his energy intake, which is below the lowest recommended percentage of the AMDR.

Whereas the AMDR expresses the recommended macronutrient intake in the context of a complete diet, the RDA (0.8 g/kg/d) has been widely applied by others as the appropriate amount, or even maximal amount, of protein intake. For example, the Dietary Guidelines published by the US Department of Agriculture adopted a recommended daily protein intake of 0.8 g/kg/d.3 Governmental programs, such as the school lunch program for children and Meals on Wheels for elderly persons use 0.8 g/kg/d as the appropriate protein intake.4 More pervasively, dietary guidelines published in the dietetic literature, the popular press, and various nutritional computer programs promulgate a protein intake of 0.8 g/kg/d. For example, in a science advisory on dietary protein and weight loss, the American Heart Association statement indicated that "Most Americans consume more protein than their bodies need."5 In fact, protein comprises an average of approximately 15% of calories for US adults,6 which is at the low end of the range recommended by the AMDR.

The problem of widespread misinterpretation and improper application of the RDA arises from the fact that the Food and Nutrition Board maintained the historically familiar term recommended dietary allowance but functionally defined it in terms misunderstood by most individuals. Thus, the term recommended implies that the RDA does not express a firm requirement, as set forth in the definition of RDA in the DRI. The distinction is that a requirement clearly defines the minimum amount needed, whereas no such implication is conveyed with the word recommended.

The definition of the term allowance in the context of the RDA is not obvious, but presumably relates to the permissible amount if the most conventional definition of allowance is used. Taken together, the logical semantical interpretation of RDA would be the permissible amount of a nutrient the committee recommends individuals should ingest each day, rather than the minimal amount of intake required to meet the nutrient requirement. However, although the term allowance implies an upper limit of intake, the DRI separately addressed the safe upper level of protein intake. It was concluded that there was no evidence documenting an upper level of protein intake beyond which adverse effects would ensue. Consequently, the DRI indicated that there is no tolerable upper intake level for protein.1

This discussion is relevant to nutrition policy only if there is evidence that the optimal level of protein intake differs from the minimal requirement. The wide range recommended in the AMDR (10%-35% of energy intake) implies uncertainty regarding the exact optimal level of protein intake. This uncertainty reflects in part a relative lack of research addressing this issue. In addition, the wide range reflects, by deduction, uncertainty regarding the optimal levels of carbohydrate and fat in the diet. For example, variations in the proportion of fat in the diet may inadvertently vary correspondingly in the proportion of protein because of an association between common sources of dietary protein and fat. These points notwithstanding, there is ample evidence that the optimal level of protein intake is greater than the RDA. A variety of studies have shown levels of protein intake above the RDA benefiting muscle mass, strength, and function,7 bone health,8 maintenance of energy balance,9 cardiovascular function,10 and wound healing.11 Close examination of these and related research studies should enable a reasonable estimation of the optimal level of protein intake in a variety of circumstances.

The solution to the dilemma of widespread misinterpretation of the RDA for macronutrients, particularly for protein, would be to accept that a discrete value cannot be assigned to each macronutrient and to use the AMDR to express the recommended intakes. Additionally, the term minimal daily requirement could replace the term recommended dietary allowance to more accurately reflect its functional definition. The introduction of more clearly defined terms would potentially have a greater benefit for nutrition policy and for individual practices than would further deliberations on the exact value of the RDAs of the macronutrients.

... ...

[King Grub]

Muscle contraction during exercise, whether resistive or endurance in nature, has profound affects on muscle protein turnover. For example, a single bout of exercise can stimulate muscle protein synthesis (MPS) in the immediate acute (1-4 h) and subsequent (8 - 72 h) time period. It is well established that feeding during the post-exercise period is required to bring about a positive net protein balance (MPS - muscle protein breakdown; MPB). There is mounting evidence that the timing of ingestion and the protein source during post during recovery independently regulate the protein synthetic response and influence the extent of muscle hypertrophy. Some minor sex-based differences in muscle turnover exist in young men and women; however, with aging there appear to be quite stark sex-based differences in response to both feeding and resistance exercise. The recognition of anabolic signaling pathways and molecules are also enhancing our understanding of the regulation of protein turnover following exercise perturbations. In this review we summarize the current understanding of muscle protein turnover in response to exercise and feeding and highlight potential sex-based dimorphisms. Further we examine the underlying anabolic signaling pathways and molecules that regulate these processes.

J Appl Physiol. 2008 Nov 26. Exercise Training and Protein Metabolism: Influences of Contraction, Protein Intake, and Sex-based differences.

http://jap.physiology.org/cgi/reprint/91351.2008v1

[Anders The Peak]

Enklast är att räkna 2gr protein per kilo fettfrimassa det är en bra tumregel vid styrketräning.
80 kg 12% fett: 1-0.12*80*2=141 gr protein och sedan fylla på med antingen 5 gr BCAA eller 10gr EAA före eller efter passet. Då har kroppen optimala möjligheter att växa.

Referens egentligen 18 veckors studien som Bengt Saltin gjorde i Danmark

http://www.gih.se/templates/ihsNormalPage.aspx?id=1535

Allmänt om kost för idrottare: http://www.rf.se/ImageVault/Images/i...ltHandler.aspx

[Fredrik_S]

Ursprungligen postat av Anders The Peak

Enklast är att räkna 2gr protein per kilo fettfrimassa det är en bra tumregel vid styrketräning.
80 kg 12% fett: 1-0.12*80*2=141 gr protein och sedan fylla på med antingen 5 gr BCAA eller 10gr EAA före eller efter passet. Då har kroppen optimala möjligheter att växa.

Vill vara lite petig "optimal"="bästa eller gynnsammast möjliga" vilket inte är möjligt att veta förens man undersökt alla andra möjliga kombination av proteinmängder och EAA mängder.
Man har tex aldrig undersökt vad som händer om man tar EAA både före och efter passet.

[Anders The Peak]

Ursprungligen postat av Fredrik_S

Vill vara lite petig "optimal"="bästa eller gynnsammast möjliga" vilket inte är möjligt att veta förens man undersökt alla andra möjliga kombination av proteinmängder och EAA mängder.
Man har tex aldrig undersökt vad som händer om man tar EAA både före och efter passet.

Kika på Bispebjergs studien som varade 14 veckor(och inte 18).
När du pratar kombinationer känns det lite som om det skulle finnas någon magisk formel för att få bästa möjliga resultat. Det är fantasier som ofta kommer från byggarartiklar/muskelbyggarmagasin, verkligheten ser inte ut så.
Om man nu ska gå ned på djupet så handlar det lika mycket om fettsyror som bygger muskler och inte endast några få aminosyror som triggar igång en mätbar muskelproteinsyntes.

[Anders The Peak]

Ursprungligen postat av Fredrik_S

Vill vara lite petig "optimal"="bästa eller gynnsammast möjliga" vilket inte är möjligt att veta förens man undersökt alla andra möjliga kombination av proteinmängder och EAA mängder.
Man har tex aldrig undersökt vad som händer om man tar EAA både före och efter passet.

Om du nu vill spekulera om vad som händer så kan du läsa den här studien:http://ajpendo.physiology.org/cgi/co...ull/281/2/E365

I en EAA blandning så är det fortfarande BCAA som stimulerar MPS dock något tidigare av någon anledning som man inte vet i dagsläget.(kombinationen av aminosyror påverkar MPS på något sätt)

[Sverker]

Ursprungligen postat av Anders The Peak

Om man nu ska gå ned på djupet så handlar det lika mycket om fettsyror som bygger muskler och inte endast några få aminosyror som triggar igång en mätbar muskelproteinsyntes.

Arakidonsyra via någon prostaglandin eller oljesyra som rent energitillskott. Har du något spännande där ?

[GasseG]

Jag vet att det snackas om proteinintagets vara eller icke vara i den här tråden men på sidan 3 så kom ni lite på testosteronhalt i blodet vs fett. Min fråga är bara som så här: Kan kolesterol var anabolt? Inte i sig självt såklart men som prekursor eller något?
Enligt hörsägen så skall sojaprotein vara sämre än vassleprotein för blodserum testosteronhalten!? Om det stämmer kan det ha att göra med kolesterolhalten?

[Cerberus]

det dåliga kolesterolet ska vara försteg till testosteron har jag läst.

[Anders The Peak]

Det finns studier som visar att de som åt relativt mycket kolesterol jämför med lågt intag av kolesterol fick betydligt bättre muskeltillväxt. I övrigt hade de rätt jämförbart näringsintag.

[Eddie Vedder]

Ursprungligen postat av Cerberus

det dåliga kolesterolet ska vara försteg till testosteron har jag läst.

Pratar du om lipoproteiner eller kolesterol nu? Det är en väldigt vanlig missuppfattning att det man kallar "det onda kolesterolet" respektive "det goda kolesterolet" är olika former av kolesterol men så är det inte. Kolesterolet som sådant är exakt detsamma, därutöver finns olika transportörer av kolesterol. LDL och HDL är de två man brukar prata mest om men även VLDL, LPL och kylomikroner transporterar kolesterol, proteiner triglycerider och fettlösliga vitaminer (kylomikronerna enbart) med olika densiteter och olika egenskaper.

[Cerberus]

det där med bärarproteiner lärde jag mig nyligen . Lipoproteiner syftade jag på.

[123123]

Ursprungligen postat av King Grub

kan man ersätta ett sånt extremt intag av protein med mumsiga kolhydrater

Kolhydrat och protein minskar proteinnedbrytning ungefär likvärdigt.

Gammal tråd, jag vet!
Undrar om man skulle kunna kunna få mer info angående detta då jag kommer att genomföra en långsiktig deff, kolhydrater är något som man hur lätt som helst får i sig, nästan t o m lika lätt som protein.

Är detta för att kolhydrater används i första hand till energi? Och sedan har man fyllt på med en del protein som ser till att musklerna får det de behöver?

[tjing]

Måttliga mängder insulin minskar kraftigt muskelnedbrytningen och du har rätt i att proteinbehoven minskar när man fyller på med mer kolhydrater.

På ett överskott är som sagt proteinbehovet sekundärt efter en viss gräns för muskeltillväxt, då metabola behov tillgodoses av övriga makronutrienter.

Dessutom minskar kolhydrater på ett underskott AMPK jämfört med ett underskott med mindre kolhydrater, vilket sannolikt har effekt på muskelnedbrytning och anabol stimulering. Det kan dock påverka fettförbränning negativt också, fastän konsensus råder om att kaloriintag är den övergripande lagen.