Post workout carbohydrate consumption does not increase protein syntesis

[Bahir]

Got this off a Swedish bodybuilding board, there was no link in the post, but still...


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The present study was designed to assess the impact of co-ingestion of various amounts of carbohydrate combined to an ample amount of protein intake on post-exercise muscle protein synthesis rates.

Ten healthy, fit men (20+/-0.3 y) were randomly assigned to 3 cross-over experiments. After 60 min of resistance exercise, subjects consumed 0.3 g.kg(-1).h(-1) protein hydrolysate with 0, 0.15, or 0.6 g.kg(-1).h(-1) carbohydrate during a 6 h recovery period (PRO, PRO+LCHO, and PRO+HCHO, respectively).

Primed, continuous infusions with L-[ring-(13)C6]phenylalanine, L-[ring-(2)H2]tyrosine, and [6,6-(2)H2]glucose were applied, and blood and muscle samples were collected to assess whole-body protein turnover and glucose kinetics as well as protein fractional synthesis rate (FSR) in the vastus lateralis muscle over 6 h of post-exercise recovery.

Plasma insulin responses were significantly greater in PRO+HCHO compared to PRO+LCHO and PRO (18.4+/-2.9 vs. 3.7+/-0.5 and 1.5+/-0.2 U.6h.L(-1), respectively: P<0.001). Plasma glucose rate of appearance (Ra) and disappearance (Rd) increased over time in PRO+HCHO and PRO+LCHO but not in PRO. Plasma glucose Ra and Rd were substantially greater in PRO+HCHO vs both PRO and PRO+LCHO (P<0.01).

Whole-body protein breakdown, synthesis and oxidation rates, as well as whole-body protein balance did not differ between experiments. Mixed muscle FSR did not differ between treatments and averaged 0.10+/-0.01, 0.10+/-0.01 and 0.11+/-0.01 %.h(-1) in the PRO, PRO+LCHO and PRO+HCHO experiments, respectively.

In conclusion, co-ingestion of carbohydrate during recovery does not further stimulate post-exercise muscle protein synthesis when ample protein is ingested.

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Am J Physiol Endocrinol Metab. 2007 Jul 3; Co-ingestion of carbohydrate with protein does not further augment post-exercise muscle protein synthesis.

EDIT: You can find something about it on this page: http://lib.bioinfo.pl/pmid:16873412

[Bahir]

Does anyone plan to comment on this?

[klosey]

/forum/images/graemlins/blush.gif yes this research all seems correct but the point of taking carbs isnt to increase protein sythesis anyway imo it is purely to replace energy used and fill the muscles depleted glycogen stores /forum/images/graemlins/cool.gif

[Venom]

My prescription to that journal has been having problems just this week, so I have to wait till they get it back up. Then I will read the full text and comment.

Thanks for posting this! Looks very interesting. /forum/images/graemlins/smile.gif

[Bahir]

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/forum/images/graemlins/blush.gif yes this research all seems correct but the point of taking carbs isnt to increase protein sythesis anyway imo it is purely to replace energy used and fill the muscles depleted glycogen stores /forum/images/graemlins/cool.gif

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I thought it was to increase protein syntesis. Just filling up the depleted glycogen stores seems kind of pointless since they will most likely be filled up with the PWO meal+other ones until you train that muscle again.

[klosey]

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/forum/images/graemlins/blush.gif yes this research all seems correct but the point of taking carbs isnt to increase protein sythesis anyway imo it is purely to replace energy used and fill the muscles depleted glycogen stores /forum/images/graemlins/cool.gif

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I thought it was to increase protein syntesis. Just filling up the depleted glycogen stores seems kind of pointless since they will most likely be filled up with the PWO meal+other ones until you train that muscle again.


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well yes.... If your post workout meal doesn't contain carbs, your body may actually instead break down muscle tissue for this same purpose. That would be a bad thing. Carbs also create an insulin spike which helps to move nutrients into your muscle tissue quicker.

[amino]

Maybe I should let Venom or Prez comment 1st since I may be performing the calculations incorrectly... But for sake of conversation here is my take.

The way I interpret this study is that through a 6 hour period they consumed a total of 3.6 grams of protein for every pound of body weight. So for a 200 pound person they would ingest 720 grams of protein??!! If that is the case, then that alone flaws this study. How can one refer to that much protein as an “ample supply”? And who as that flexible of a schedule to ensure this happens within 6 hours every workout day?

Thus, seems to me that using dextrose/maltodextrin (as a insulin response transport) in your post-workout meal allows the 6 hour recovery period to be shrunk down to one hour and the ample supply of protein to be reduced from 700g to 40g.

Seems to me that the Window of Opportunity method is much more efficient.

[sucramdw]

I am not sure where your seeing 3.6. I think it is .3g of protein per kg of bodyweight per hour for a 6 hour recovery period, which would be around 163.6g of protein for a 200lb person.

However the entire study would need to be read here to accurately assess what is going on.

[Venom]

Just briefly browsed the study.

Essentially, the primary reason athletes have carbohydrates post exercise is to 1.) rapidly replenish glycogen 2.) Increase protein balance 3.) Improve recovery / decrease muscle damage.

There is no question that carbohydrates immediately post exercise are optimal for replenishing glycogen stores; and delaying them will impair the rate and amount of glycogen replenishment. Hence, why endurance athletes in particular consume a lot of high glycemic carbohydrates post exercise, along with protein which augments insulin and glycogen replenishment.

Now bodybuilders are really interested in the second effect. Protein balance is the difference between protein synthesis (the manufacturing of proteins) and protein degredation (the breaking down of proteins).

Studies are very clear that protein is the primary regulator of protein synthesis. In fact, it appears that leucine is the primary signal for protein synthesis, and the essential amino acids in particular are vital for prolonging and facilitating this effect. Hence, the amino acid shooter formula. Read this article for more information on this, http://www.abcbodybuilding.com/leucineindex.php

Now protein degredation is a different story. Carbohydrates and fats are considered the primary regulators of this, and for sparing proteins. Which is why bodybuilders typically stack protein meals with an energy source from either carbs and fats.

Studies I have seen indicate that total protein balance is higher when proteins and an energy source are combined. The energy source usually has minimal effect on protein synthesis, but rather works primary through decreasing degradation.

Anyway, this study showed that protein synthesis was not significantly different when carbohydrates were co-ingested with proteins. Not surprising to me.

What was surprising was that protein degredation was not significantly different either. This is in stark contrast to the research I have read, and even studies which they pointed out in their intro. They gave no explanation why this was the case. There conclusion was more similar to their results section in this respect.

So I am not sure about that. I will have to investigate that more. One suggestion I have is that the protocol did not effect protein degredation enough for carbs to have an effect.

One problem I have, is that I did not see a placebo, or a pre-test measurement of protein degredation. So right now, I have no idea by what magnitude protein degredation changed pre to post exercise. But I’ll have to look at the study closer to confirm this.

They also did not measure catabolic hormones such as cortisol. Which I would expect to be much lower. I don’t think they measured 3 methyl histidine, which is a good indicator of protein degredation.

Now back to protein synthesis. I have a study that would be awesome to do.

There are studies on mixed meals, especially in the elderly, that show that if you combine protein, with a large meal (i.e. 700 calories) protein synthesis lowers. The rational is slower digestion rates. It appears that the faster aminos / proteins are digested, the greater protein synthesis is.

SO here is my study proposal. Compare the effects of slow vs. fast digesting carbohydrates stacked with proteins / aminos on protein balance. Example:

Oatmeal w/ essential aminos
Dextrose w/ essential aminos
A bunch of leafy greens w/ essential aminos
essential aminos

In this case, even if none of these sources of energy improve protein synthesis, what if things such as oatmeal and leafy greens actually decrease protein synthesis? I would hypothesis that they would, because they would slow digestion.

Let me know what you think…


On another subject, muscle damage was not measured in this study. I did a lot of research on this for my Masters program, and am doing some experimentation right now. Here is a brief run down.

Muscle damage theory considers damage caused to muscles, particular at the level of z-lines. From a functional view, muscle damage is characterized by a prolonged decrease in performance (from several days to weeks).

Based on the literature, Warren et al. (1999) suggest that the gold standards for muscle damage measurements are force and ROM measurements. This is due to their high reliability scores, and because they are objective ways of characterizing functional deficits resulting from muscle damage, making them very applicable to clinical and athletic populations.

Other measurements include blood markers of damage such as creatine kinase, measures of soreness (DOMS), among others. If you guys have any questions on this, let me know.

Based on my research, you may be surprised to know that proteins actually are much more important for decreasing muscle damage than carbohydrates. However, carbohydrates do have a role, and definitely can assist in decreasing muscle damage and increasing recovery time.

So it would have been good to measure muscle damage as well.

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Just filling up the depleted glycogen stores seems kind of pointless since they will most likely be filled up with the PWO meal+other ones until you train that muscle again.

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Problem is that glycogen depletion can become a chronic issue, and you also will not replenish glycogen nearly as fast as you will post exercise. Meaning that you will need to consume more carbohydrates to compete with the amount of carbs you could consume post exercise to replenish glycogen. This quote from old school somes up my thoughts on glycogen replenishment.

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Often proponents of slow burning carbohydrates post-workout will take studies out of context claiming, “Rapid glycogen synthesis via insulin post-workout is unnecessary. Most body building training programs incorporate several rest days before the same muscle group is trained again; therefore, glycogen depletion is not a big issue in bodybuilding. After all, I train my shoulders only once per week; there is plenty of time in between to restore glycogen!”

However, this is hasty generalization (understand also that this is ignoring a host of other benefits glucose feeding post-training has in regards to anabolism).

D. L. Costill, D. D. Pascoe, W. J. Fink, R. A. Robergs, S. I. Barr, and D. Pearson reveled in their study, “Impaired muscle glycogen resynthesis after eccentric exercise,” (J Appl Physiol 69: 46-50, 1990) that glycogen synthesis is hindered post-eccentric exercise.

The heavy utilization of the eccentric factor in the body builder’s code of behavior makes this study even more imperative for the hypertrophy athlete. In light of this obstruction, it would be foolhardy not to act in a fashion that would allow for the most advantageous recovery, such as is the case with sub-optimal carbohydrate foundations post-workout.

Consider, also that even if an athlete trains his or her shoulders directly only once per week, they are still training chest, back, trapezius, arms, and integrating other various compound exercises that incorporate heavy use of the deltoids, either as prime or secondary movers, synergists or as dynamic stabilizers. No doubt this is supported by DOMS and ingrained through kinesthetic proprioception.

The deltoids are taking an extreme breakdown multiple days in a row (and this is the case with a manifold of large and small muscle groups, for example the back, calves, and abdominals). Furthermore, eccentric exercise has been shown to impair glycogen synthesis.

Additionally, myofibril hydration is crucial as “glucose and sodium post-exercise greatly enhance intestinal fluid absorption over plain water, due to the Glucose/Sodium co transport system”

(See: Effect of Plasma Volume on Myofibril Hydration, Nutrient Delivery, and Athletic Performance).

Replacing glycogen stores rapidly as possible is the most logical conclusion for body builders who train multiple days or follow typical body building splits and exercise programs.



Furthermore, there is no logical reason not to intake High GI carbohydrates post-workout. Excess fat gain from high GI carbohydrate sources is the only reason asserted, and this is based on ignorance of post-exercise carbohydrate metabolism.



Will one make gains without high GI carbohydrates post-workout? Some progress can be made without these factors.

Will optimal performance and maximal potential gains suffer under such a protocol? Science and logic have shown the answer to be an overwhelming and resounding, “yes”.

Delaying the consumption of nutrients post-workout, via the intake of low GI carbohydrates like fat and fiber, has been shown to be self-impeding and rationally inconsistent for body building practices.

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[President Wilson]

I read the study and I have two possible explanations.

1. As Venom discussed it is not surprising that the carbs did not enhance protein synthesis. However, the finding that they did not decrease breakdown is fascinating and may very well be linked to the pattern of digestion.

Heres some background information

A. Slow digesting proteins lower protein degradation
B. Fast digesting proteins do not have this same effect.
C. The reason that slow digesting proteins effect degradation is that they cause amino acids to rise moderately and then remain elivated for a period of several hours. This is known as prolonged hyperaminoacidemia. It appears that prolonged hyperaminoacidemia is a powerful modulator of protein degradation. Check out our paper here
http://www.sportsnutritionsociety.org/site/pdf/JISSN-3-1-7-27-06.pdf
and scroll down to the effect of digestion rate. There we discuss
what prolonged hyperaminoacidemia does and list several studies on the subject

Now when you add a carbohydrate to a fast digesting protein, protein breakdown is lowered, but when you add a carbohydrate to a slow digesting protein like casein degradation is barely affected, because the amino acids had already lowered this, and
insulin did not lower it further.

In this study, the mimicked the pattern of digestion seen in slow digesting proteins by feeding participants small servings of the protein every 30 minutes instead of giving it to them all at once.
If you look at the data this created a moderate rise in plasma amino acids which was maintained at steady state for 360 minutes, thus it would have a powerful effect on protein degradation of which insulin would not lower it further.

2. The second explanation was explained by a reference by Dr. Rennie that was listed in the paper. Here the authors postulated that the protein was actually able to raise insulin levels to a threshold high enough to maximize protein balance without carbohydrates. Here is the quote from the manuscript

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Even in the absence of
carbohydrate co-ingestion, plasma insulin levels averaged 16.5±1.6 μU·ml-1 during the 6 h
recovery period in the PRO treatment. Interestingly, it was recently suggested by Rennie et al
(27) that an increase in insulin levels above 10-15 μU·ml-1 does not further enhance muscle
protein synthesis and/or reduce protein degradation.

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In summary two explanations are that (1) the way the authors administered the protein caused prolonged hyperaminoacidemia which lowered protein degradation to a point where an increase in insulin would do very little in the cause of lowering it further (2) the protein had already stimulated enough rise in insulin such that further increases would have no greater effect.

Finally its critical to remember that this is an acute study. There are many questions which stem from this that would be fascinating to see in a long term study

[Venom]

Incredible analysis, president!


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If you look at the data this created a moderate rise in plasma amino acids which was maintained at steady state for 360 minutes, thus it would have a powerful effect on protein degradation of which insulin would not lower it further.

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This also is not very practical, because most would not have small boluses of protein every 30 minutes for 6 hours!!!

So if you were to have one bolus of amino acids protein post exercise, stacked with carbs immediately, the results probably would definitely differed. Most likely, protein synthesis would be higher, and protein degredation would also have been lower with carb supplementation.

[President Wilson]

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So if you were to have one bolus of amino acids protein post exercise, stacked with carbs immediately, the results probably would definitely differed. Most likely, protein synthesis would be higher, and protein degredation would also have been lower with carb supplementation.

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Exactly,

and I think that this is what the work of Boire and Dangdin and colleagues have demonstrated. So we need two studies to follow from this one

1. Do these effects remain under one large bolus ingestion of EAAs

2. What r the chronic effects

Overall this is a great study though, great job posting it!

[Venom]

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1. Do these effects remain under one large bolus ingestion of EAAs

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Tipton has actually tested this a few times.

From what I am seeing, protein balance is greater when you combine EAA’s with carbohydrates. And the primary mechanism appears to be decreased protein degradation via insulin. Though, he had some really fascinating ideas on how carbs may even improve protein synthesis when stacked with proteins, if the right form of proteins is consumed (this is a long discussion, so I won’t get into this).



Medicine & Science in Sports & Exercise:Volume 33(5) Supplement 1May 2001p S176

POST-EXERCISE MUSCLE PROTEIN ANABOLISM: STIMULATION BY AMINO ACIDS PLUS CARBOHYDRATE VS AMINO ACIDS OR CARBOHYDRATE ALONE

Miller, S L.1; Tipton, K D.1; Wolf, S E.1; Wolfe, R R. FACSM1
1University of Texas Medical Branch, Galveston, TX

Previous work showed enhanced muscle protein anabolism following resistance exercise when essental amino acid plus carbohydrate was ingested. Indirect evidence suggests that carbohydrate alone improves muscle anabolism by diminishing muscle protein breakdown via insulin. This study investigated net phenylalanine (PHE) uptake as an index of muscle protein balance in healthy volunteers ingesting 1 of 3 drinks. Drinks, taken at 1 and 2h post-exercise, provided either 0.0857 gm/kg balanced amino acid mixture (AA), 0.5 gm/kg carbohydrate (CHO), or 0.0857 gm/kgw AA plus 0.5 gm/kg CHO (MIX). Femoral arterial and venous blood samples were collected during the 3h recovery period following exhaustive leg exercise. Net PHE balance was calculated from blood concentrations and blood flow as determined by dye dilution. Area under the curve (AUC) of net PHE uptake indicated significantly greater uptake of PHE during 3h recovery when MIX was consumed compared to CHO alone (119 ± 29 vs 64 ± 18 and 39 ± 9 mg/min, for MIX, AA, and CHO respectively. P < 0.05, n = 7 trials/drink). Insulin AUC was also significantly elevated in MIX relative to AA (MIX, 3303 ± 310; AA, 1042 ± 165; CHO, 2599 ± 205, P < .001) suggesting a combined effect of AA stimulated muscle protein synthesis and insulin suppression of muscle protein breakdown to optimize net muscle protein synthesis.

Here is another very similar investigation.

Medicine & Science in Sports & Exercise, 2003.

Independent and combined effects of amino acids and glucose after resistance exercise.
Miller SL, Tipton KD, Chinkes DL, Wolf SE, Wolfe RR.
Dairy Management, Inc, Rosemont, IL, USA.
PURPOSE: This study was designed to assess the independent and combined effects of a dose of amino acids (approximately 6 g) and/or carbohydrate (approximately 35 g) consumed at 1 and 2 h after resistance exercise on muscle protein metabolism. METHODS: Following initiation of a primed constant infusion of H -phenylalanine and N-urea, volunteers performed leg resistance exercise and then ingested one of three drinks (amino acids (AA), carbohydrate (CHO), or AA and CHO (MIX)) at 1- and 2-h postexercise.(5) RESULTS: Total net uptake of phenylalanine across the leg over 3 h was greatest in response to MIX and least in CHO. The individual values for CHO, MIX, and AA were 53 +/- 6, 114 +/- 38, and 71 +/- 13 mg x leg x 3h. Stimulation of net uptake in MIX was due to increased muscle protein synthesis. CONCLUSIONS: These findings indicate that the combined effect on net muscle protein synthesis of carbohydrate and amino acids given together after resistance exercise is roughly equivalent to the sum of the independent effects of either given alone. The individual effects of carbohydrate and amino acids are likely dependent on the amount of each that is ingested. Further, prior intake of amino acids and carbohydrate does not diminish the metabolic response to a second comparable dose ingested 1h later.


Essentially, results showed that the effects of stacking carbs with aminos was additive on protein balance.

They said there was not a significant difference however, between aminos and carbs + aminos on protein balance. But they did not report the p value. I bet it was like p=.06. I just did a paper on p values that has been accepted for publication, and they are really meaningless. Really effect sizes are what counts. And the effect size here was clear.

I'll post a graph once we make sure our server is fine.

The uptake of phenylalanine by muscle (used to infer protein synthesis) were 53, 71, and 114 for CHO, amions, and CHO +aminos respectively. Which indicates that CHO and aminos were additive on improving protein balance.

Here is another quote from their article on the effects of carbohydrates on protein degredation.

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Previous studies have provided some evidence that carbohydrate
ingestion alone improves protein metabolism.
Rennie et al. showed improved leucine balance during carbohydrate
supplemented endurance exercise (13), whereas
Roy et al. reported diminished myofibrillar proteolysis when
carbohydrate was ingested following resistance exercise
(14). Our results are consistent with this latter observation,
as both urea production and Phe Ra were significantly lower
in the CHO group relative to the predrink value at 30 min,
and net balance was greater than zero throughout the 3 h
after ingestion (Fig. 6).

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[Venom]

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2. What r the chronic effects

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Ask and you shall...

This study by Bird (2006) showed that after 12 weeks of resistance training twice weekly, consuming CHO+ EAA post exercise increased muscle mass to a greater extent, lowered protein degredation, raised insulin and lowered cortisol to a greater extent than CHO or EAA's alone.

1: Eur J Appl Physiol. 2006 May;97(2):225-38. Epub 2006 Mar 24.

Independent and combined effects of liquid carbohydrate/essential amino acid ingestion on hormonal and muscular adaptations following resistance training in untrained men.

Bird SP, Tarpenning KM, Marino FE.
School of Human Movement Studies, Charles Sturt University, Allen House 2.13, Bathurst, NSW, Australia. sbird@csu.edu.au
This investigation examined chronic alteration of the acute hormonal response associated with liquid carbohydrate (CHO) and/or essential amino acid (EAA) ingestion on hormonal and muscular adaptations following resistance training. Thirty-two untrained young men performed 12 weeks of resistance training twice a week, consuming ~675 ml of either, a 6% CHO solution, 6 g EAA mixture, combined CHO + EAA supplement or placebo (PLA). Blood samples were obtained pre- and post-exercise (week 0, 4, 8, and 12), for determination of glucose, insulin, and cortisol. 3-Methylhistidine excretion and muscle fibre cross-sectional area (fCSA) were determined pre- and post-training. Post-exercise cortisol increased (P<0.05) during each training phase for PLA. No change was displayed by EAA; CHO and CHO + EAA demonstrated post-exercise decreases (P<0.05). All groups displayed reduced pre-exercise cortisol at week 12 compared to week 0 (P<0.05). Post-exercise insulin concentrations showed no change for PLA; increases were observed for the treatment groups (P<0.05), which remained greater for CHO and CHO + EAA (P<0.001) than PLA. EAA and CHO ingestion attenuated 3-methylhistidine excretion 48 h following the exercise bout. CHO + EAA resulted in a 26% decrease (P<0.01), while PLA displayed a 52% increase (P<0.01). fCSA increased across groups for type I, IIa, and IIb fibres (P<0.05), with CHO + EAA displaying the greatest gains in fCSA relative to PLA (P<0.05). These data indicate that CHO + EAA ingestion enhances muscle anabolism following resistance training to a greater extent than either CHO or EAA consumed independently. The synergistic effect of CHO + EAA ingestion maximises the anabolic response presumably by attenuating the post-exercise rise in protein degradation.


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So we need two studies to follow from this one

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Got any other ideas? /forum/images/graemlins/tongue.gif

[MartinofSweden]

Hey Gabe, that´s good info, but if I´m understanding this right the study above doesn´t really answer the question. What would be the effect of a very large dose of EAA vs the effect of CHO + EAA? Or more percicely, is there any degree at which EAA stimulates both protein synthesis and inhibits protein breakdown, in the post exercise state, which is not further enhanced by CHO? If there is, what are the mechanisms? If indeed one major mechanism is hyperinsulinaemia (although I´ve read studies that show BCAAs slow catabolism even in the absence of insulin), then it´s hard for me to understand why this could´t be achieved with proteins only. Even though easily digested nutrients cause a more rapid rise of insulin, insulin secretion is mainly a matter of energy quantity, isn´t it? I find this a very interesting thread by the way, thanks for the input!

[Venom]

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Or more percicely, is there any degree at which EAA stimulates both protein synthesis and inhibits protein breakdown, in the post exercise state, which is not further enhanced by CHO? If there is, what are the mechanisms?

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Too my knowledge this has not been shown. So I can't really say for sure.

The mechanism by which carbohydrates decrease protein breakdown, and may stimulate protein synthesis is commonly attributed to insulin. So if proteins were able to maximally stimulate both, then the mechanism would probably be attributed to optimal levels of insulin.

The effects of insulin on protein synthesis is extremely complicated and the results are not very consistent. I do have some study ideas on how to test this. But for sure, there is a lot of controversy on whether carbs are needed to stimulate protein synthesis.

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Even though easily digested nutrients cause a more rapid rise of insulin, insulin secretion is mainly a matter of energy quantity, isn´t it?

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Substrate, too. Leucine can independently increase insulin concentrations. While the other amino acids act synergistcally with carbohydrates to increase insulin.