3g Taurine Improve Post-Workout Glycogen Resynthesis, Protect the Testes of Doping Sinners & Battles Alzheimer's

Taurine - A useful supplement for chemical, natural athletes and even sedentary slobs who are afraid of diabetes.

Taurine, or 2-aminoethanesulfonic acid, as Wikipedia says, is an organic acid widely distributed in animal tissues. It is a major constituent of bile and can be found in the large intestine, and accounts for up to 0.1% of total human body weight. That does not sound like much, but taurine has many fundamental biological roles, such as conjugation of bile acids, antioxidation, osmoregulation, membrane stabilization, and modulation of calcium signaling. It is essential for cardiovascular function, and development and function of skeletal muscle, the retina, and the central nervous system and you were thus probably not too surprised, when you've recently read on the SuppVersity Facebook Page that taurine may help with Alzheimer's disease.

You can learn more about taurine & other amino acids at the SuppVersity

Taurine Pumps Up Strength & Recovery?

Taurine Improves Insulin + Glucose Metabolism

Taurine ➲ 180% Testosterone Increase

Taurine + BCAA Work Hand in Hand

43% Reduced Performance W/ BCAAs

BCAA Neurotransmitter Depletion

In the corresponding paper that was published only recently in the ScientificReports on Nature.com Kim et al. report that orally administered taurine via drinking water rescued the cognitive deficits in a standard rodent model of Alzheimer's (APP/PS1 mice) and brought them back up to age-matching wild-type mice.

Figure 1: Improvement in spatial and hippocampal learning behaviours in taurine-treated transgenic mice. 7-month old wild-type (Wt) and agematched APP/PS1 transgenic (Tg) male mice were orally administered water or taurine (1,000 mg/kg/day) for 6 weeks (n 5 8–10 per group). After 6 weeks, behavioural tests were administered to the 8.5-month old mice. (Left) Y-maze. Average alternation (%) of each group of mice was calculated. (Right) Passive avoidance. Average latency time in seconds for each group of mice was measured (Kim. 2014).

That's unquestionably impressive, but what's more impressive is that this is by far not the first study to report that taurine exhibits a plethora of physiological functions in the central nervous system.

But taurine gives me diarrhea! If it does try taking it with a meal that will greatly reduce the risk of having to rush to the toilette and should not reduce the physiological benefits significantly. At least for the muscular effects its unlikely that it will matter at all. For the beneficial effects on the brain, it may be necessary to achieve higher serum peak levels. In view of the fact that the rodents in the aforementioned study by Menzie et al. received the taurine in the drinking water, even this is yet unlikely. If the taurine "goes right through", though, it's certainly not going to help you ;-)

In a recent review in the scientific journal Amino Acids review, Janet Menzie et al. describe the mode of action of taurine and its clinical application in the neurological diseases: Alzheimer’s disease, Parkinson’s disease and Huntington’s disease and conclude that taurine...

"[...] functions through multiple neuroprotective mechanisms: regulation of cellular osmolarity , anti-oxidant, neuromodulator of GABAergic transmission, maintenance of calcium homeostasis, inhibition of glutamate excitotoxicity, attenuation of endoplasmic reticulum stress, modulation of mitochondrial pore permeability, downregulation of a range of proapoptotic proteins while upregulating anti-apoptotic proteins and downregulation of inflammatory mediators." (Menzie. 2014)

Moroever, Menzie et al. believe that there is "strong evidence" of the existence of a specific taurine receptor, which is activated exclusively by taurine, but not by structurally similar amino acids such as glutamate, GABA and glycine and could be responsible for many of the beneficial effects taurine exerts in the context of central nervous system disorders. More specifically existing evidence clearly suggests protective effects in Alzheimer’s, Parkinson and Huntington diseases. Three pathologies that share a number of broad mechanisms: Oxidative stress, mitochondrial dysfunction, excitotoxicity, calcium imbalance, inflammatory changes apoptosis - and *tadaa* a reduced level of (Arai. 1985; Alom. 1991; Molina. 1997).

Enough of the health stuff, what about the post-workout goodness?

I know, as long as we are healthy we don't really care about debilitating central nervous system disorders... well, ok. I will spare you my moral pointing finger and get straight to the similarly unsurprising results of a recent study from the University of Tokyo. A study which clearly indicates that the provision of taurine after workouts can lead to a significant enhancement of the already elevated glycogen synthesis after your workouts.

Figure 2: Muscle and liver glycogen and serum free fatty acids (FFA) before and after the workout (Takahashi. 2014).

In two rodent studies, the Japanese researchers tested whether the oral administered of taurine  at a dosage of 0.5 g/kg body weight (for human beings that's 0.04g/kg or approximately 3g total | the SuppVersity suggested dose from previous articles, by the way) immediately after treadmill running at 25 m/ min for 90 min would alter the metabolic response and glycogen synthesis after workouts when it was (A) administered alone or (B) as part of a glucose solution containing taurine and glucose at a ratio of 1:2 - in this case 0.5g/kg taurine and 1.0g/kg glucose.

Figure 3: AUC for glucose after for 60min and 120min after the ingestion of the taurine + glucose solution. As the data indicates taurine helped to "clear" the sugar from the blood stream (Takahashi. 2014).

As the scientists point out, their "results show that post-exercise taurine administration enhances glycogen repletion in skeletal muscle" (Takahashi. 2014). The underling cause, however, is still speculative. Takahashi et al. believe that it is triggered by

1. 

   Figure 4: Changes in general oxidative damage (TBARs), protein damage and exercise performance in response to taurine vs. placebo vs. bet alanine supplementation; expressed relative to untrained control (Dawson. 2002).

   an acceleration of glucose uptake, and
2. an increase in fat oxidation

of which the latter will have a carbohydrate sparing effect and will thus leave a higher amount of carbs for glycogen repletion. In conjunction with previously established benefits of taurine, such as

• the attenuation of exercise-induced DNA damage during workouts (young men | Zhang. 2004),
• the amelioration of cytotoxic (cell damaging) effects of exercise (rodents | Dawson. 2002),
• an increase in exercise performance (specifically endurance ex. | Dawson. 2002; Miyazaki. 2004),
• additional effects on the benefits of BCAA intake for the delayed-onset muscle soreness and muscle damage induced by high-intensity eccentric exercise (Ra. 2013),
• an improvement in osmoregulation (water balance) of the muscle (Cuisinier. 2002), and
• decreases in oxidative stress during eccentric exercises (Silva. 2011)

The optimal dosing for performance increments, by the way, is between 1.2-6.0g for 2 weeks (other timing has not been tested, so it's possible that one week will suffice, too). That's at least what the only hitherto published study that investigated the effects of different doses of taurine as a means to improve the endurance performance (Miyazaki. 2004). If you want the nutrient partitioning effects, though, you would have to consume CHO + taurine after the workout - 3g of taurine should suffice. Judged by the hitherto published studies this should automatically help you to increase your workout performance after 2 weeks (the beneficial effects will, just as it is the case for creatine, accumulate until the levels are saturated).

And there are more benefits - health benefits, for juicers and non-juicers

The former, i.e. the juicers will probably be happy to hear that taurine does not just have liver protective effects (Miyazaki. 2005), but will also reverse the nandrolone decanoate induced perturbations in sperm characteristics, normalize the serum testosterone level, and restore the activities of the key steroidogenic enzymes in rodents that are treated with nandrolone and taurine (at a dosage equivalent to only 1.3g/day | Ahmed. 2014).

In spite of the fact that the administration of taurine did also prevent the nandrolone decanoate-induced testicular toxicity and DNA damage by virtue of its antioxidant, anti-inflammatory, and anti-apoptotic effects, I would like to point out that this article is not intended as an incentive for nandrolone doping.

While taurine is not made from the sperm of Belgian Blues it may still boost your testosterone levels - whether that's going to be by 140% as in this study is questionable, though.

From performance to health doping: If you are not into "natural performance enhances" and don't care about the direct performance increases, reduced oxidative damage and increases in glycogen repletion during workouts. I would recommend you reread the previous SuppVersity article about the testosterone boosting effects of taurine, it's ability to improve your strength and recovery during and after resistance training sessions, as well as it's ability to improve your glucose metabolism (Franconi. 2006; Carneiro. 2009), to increase your glucose sensitivity (Han. 2004; Nakaya. 2000), to prevent insulin resistance in hyperglycemic states (Haber. 2003), to prevent the development of hypertension as a result of fructose overfeeding (Rahman. 2011), to prevent the cardiac damage due to iron overload (Oudit. 2004), to protect you from the kidney damaging assault of chemotherapy (Saad. 2010), and god knows which benefits I have simply forgotten in the aforementioned list | Comment of Facebook!

References:

• Ahmed, Maha AE. "Amelioration of Nandrolone Decanoate-Induced Testicular and Sperm Toxicity in Rats by Taurine: Effects on Steroidogenesis, Redox and Inflammatory Cascades, and Intrinsic Apoptotic Pathway." Toxicology and Applied Pharmacology (2014).
• Alom, J., et al. "Cerebrospinal fluid taurine in Alzheimer's disease." Annals of neurology 30.5 (1991): 735-735.
• Arai, Heii, et al. "A preliminary study of free amino acids in the postmorten temporal cortex from Alzheimer-type dementia patients." Neurobiology of aging 5.4 (1985): 319-321. 
• Carneiro, Everardo M., et al. "Taurine supplementation modulates glucose homeostasis and islet function." The Journal of nutritional biochemistry 20.7 (2009): 503-511.
• Cuisinier, Claire, et al. "Role of taurine in osmoregulation during endurance exercise." European journal of applied physiology 87.6 (2002): 489-495.
• Dawson Jr, R., et al. "The cytoprotective role of taurine in exercise-induced muscle injury." Amino acids 22.4 (2002): 309-324. 
• Franconi, Flavia, et al. "Taurine supplementation and diabetes mellitus." Current Opinion in Clinical Nutrition & Metabolic Care 9.1 (2006): 32-36.
• Haber, C. Andrew, et al. "N-acetylcysteine and taurine prevent hyperglycemia-induced insulin resistance in vivo: possible role of oxidative stress." American Journal of Physiology-Endocrinology and Metabolism 285.4 (2003): E744-E753.
• Han, Jin, et al. "Taurine increases glucose sensitivity of UCP2-overexpressing β-cells by ameliorating mitochondrial metabolism." American Journal of Physiology-Endocrinology and Metabolism 287.5 (2004): E1008-E1018. 
• Kim, Hye Yun, et al. "Taurine in drinking water recovers learning and memory in the adult APP/PS1 mouse model of Alzheimer's disease." Scientific Reports 4 (2014).
• Menzie, Janet, et al. "Taurine and central nervous system disorders." Amino acids 46.1 (2014): 31-46.
• Miyazaki, T., et al. "Optimal and effective oral dose of taurine to prolong exercise performance in rat." Amino Acids 27.3-4 (2004): 291-298.
• Miyazaki, Teruo, et al. "Taurine inhibits oxidative damage and prevents fibrosis in carbon tetrachloride-induced hepatic fibrosis." Journal of hepatology 43.1 (2005): 117-125.
• Molina, José A., et al. "Decreased cerebrospinal fluid levels of neutral and basic amino acids in patients with Parkinson's disease." Journal of the neurological sciences 150.2 (1997): 123-127.
• Nakaya, Yutaka, et al. "Taurine improves insulin sensitivity in the Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous type 2 diabetes." The American journal of clinical nutrition 71.1 (2000): 54-58.
• Oudit, Gavin Y., et al. "Taurine supplementation reduces oxidative stress and improves cardiovascular function in an iron-overload murine model." Circulation 109.15 (2004): 1877-1885.
• Rahman, Mizanur M., et al. "Taurine prevents hypertension and increases exercise capacity in rats with fructose-induced hypertension." American journal of hypertension 24.5 (2011): 574-581.
• Saad, Sherif Y., and Ammar C. Al-Rikabi. "Protection effects of taurine supplementation against cisplatin-induced nephrotoxicity in rats." Chemotherapy 48.1 (2010): 42-48.
• Silva, Luciano A., et al. "Taurine supplementation decreases oxidative stress in skeletal muscle after eccentric exercise." Cell biochemistry and function 29.1 (2011): 43-49. 
• Takahashi, Yumiko, et al. "Post-exercise taurine administration enhances glycogen repletion in tibialis anterior muscle." The Journal of Physical Fitness and Sports Medicine 3.5 (2014): 531-537.
• Zhang, M., et al. "Role of taurine supplementation to prevent exercise-induced oxidative stress in healthy young men." Amino acids 26.2 (2004): 203-207.

Leucine Only Tops Ergogenic Effects of BCAAs: Increased Alanine Cycle Activity Spares Muscle Glycogen, Boosts Endurance Performance - BCAAs Have Opposite Effect

Alanine is the liver's favorite gluconeogenic amino acid and leucine appears to increase its usage.

Being among the first to learn about the "Glucose-Repartitioning Effect of Iso-Leucine" in February 2013 (read up on it), you, as SuppVersity reader, belong to the selected few who know that valine and isoleucine may be more than unnecessary props in the leucine-powered BCAA show. With the recent publication of a rodent study from the University of Sao Paulo in Brazil (Campos-Ferraz. 2013), however, it looks as if you had to revise your perspective on the purportedly auxiliary BCAAs - at least, with respect to their ability to reduce fatigue, and muscle and liver-glycogen degradation, in trained rats and possibly (!) humans.

So what did the Brazilian researchers do?

Basically, the idea Campos-Ferraz et al. had in mind, when they came up with their 8 week exercise + 2 week supplementation protocol (see Table 1) was to ...

Table 1: Exercise progression; suppl. was initiated in w7 after lactate test

"evaluate effects of the use of supplementation with leucine or a mixture of BCAAs in trained rats submitted to an exercise-induced protocol of glycogen depletion.

Furthermore, we attempted to investigate muscle and liver biochemical parameters that were not performed in the previous study in order to elucidate the role of BCAAs in glycogen depletion. " (Campos-Ferraz. 2013)

In other words: The researchers wanted to find out whether or not leucine would exert identical, less or more pronounced effects on muscle glycogen use and endurance performance in rodents that the full spectrum of branch-chained amino acids, i.e. leucine, valine and isoleucine.

Contrary to what bro-science and the shiny ads of the supplement industry are suggesting, the scientists' fundamental hypothesis was that the BCAAs supplementation would impair the rodents endurance capacity, because the branched-chain amino acids would be used in muscle to yield acetyl-CoA. This, in turn could reduce the activity of the glucose-alanine cycle, by which the muscles are supplied with alanine-derived glucose from the liver and (once the BCAAs got burne) result in an earlier onset of fatigue.

BCAAs are "glycogen depleters"?!

If you take a look at the data Campos Ferraz et al. gathered in the testing sessions at the end of the supplementation period, in the course of which the rats received an oral gavage of 166mg/kg per day (in human terms this would be ca. 3-3.5g per day) of BCAAs or leucine, it is quite obvious that the  the leucine group had a significantly lower muscle and liver glycogen degradation ratios than the BCAA group.

Figure 1: Liver & mucle glycogen degradation and time to exhaustion (expressed relative to placebo); muscle TCA intermediate content and enzyme activity / concentration (Campos-Ferraz. 2013)

Compared to the placebo group, only the ratios were different.  While the placebo group had the lowest liver glycogen use and a high muscle glycogen use, the supplemental leucine induced a shifted from muscle to liver glycogen and did thus exert muscle specific glycogen sparing effects.

As the researchers point out, these observations stand in line with their original hypothesis: Leucine can spare a significant amount of muscle and liver glycogen and thus produce a highly significant increase in resistance to exhaustion compared to the mixture of BCAAs (P<0.001).

This is not the first study to cast a bad light on BCAA supplementation. As a SuppVersity veteran, you will remember my November 2012 article "Chronic High Dose BCAA Supplementation Reduces Endurance Performance by 43%" | read more, as well as the more recent investigation into the  "Neurotransmitter Depleting Effects of Branched Chain Amino Acids (BCAAs) and Their Potential Ergolytic, Anxiogenic & Depressive Downstream Effects" | read more.

If we compare the endurance performance of the leucine rodents to that of the placebo group, this does yet cast a slight shadow on the overall image of the glorious ergogenic, and, even more so, the purported performance enhancing effects of BCAAs. Despite measurable differences in the time to exhaustion, the actual endurance increase in response to the leucine supplement is relatively small.
 
If you take another look at the data in Figure 1 you will probably notice the significant increase in TCA cycle intermediates (citrate and malate) in the BCAA group. These changes provide further evidence that the provision of all three branch-chain amino acid emphasized the use of glucose as a main substrate to sustain the endurance activity.

"Mouse vs. man": Can we ignore the differences in BCAA metabolism?


At this point, it may however be about time to point out that the activity of the BCAA catabolizing enzyme branched-chain keto acids dehydrogenase complex (BCKD) in humans is quite different from that in rats.

"In the latter [the rat], liver BCKD is almost completely unphosphorylated (activated) in basal state, making it possible to metabolize more rapidly BCKA from the portal blood; in humans, BCKD in liver is normally phosphorylated (inactivated) in order to spare BCAAs for protein synthesis." (Campos-Ferraz. 2013)

In other words: While rodents use BCAAs mostly as an energy source, the human body spares them as a potential protein anabolic.

In view of the fact that the BCAAs are not used to the same degree as an alternative substrate in the human vs. the rodent liver, it is actually not very surprising that the results of the study at hand appear to conflict with data from a previous study by the same laboratory (Gualano. 2011). In the corresponding experiment, Gualano et al observed measurable increases in exercise capacity and lipid oxidation in human subjects during endurance exercise after muscle glycogen depletion in response to the provision of 300mg/kg BCAAs per day.

So, the study is totally irrelevant, right? Not really, no. The fact that we are not able to use BCAAs as a readily available energy source like rodents does after all not mean that they must necessarily have the opposite effects on us. In fact, you all know that the vast majority of studies investigating the beneficial effects of BCAAs on endurance performance in humans yielded a null-result (!) - despite the fact fact that generations of researchers have been convinced that the inhibition of tryptophan uptake must blunt the exercise induced onset of fatigue (learn more in the articles cited in the red box).

Don't forget the endurance reducing increase in glucose usage that appears to be caused by isoleucine (and maybe valine) can also be beneficial: "The Glucose Repartioning Effects of Isoleucine" | read more.

The actual new information this study brings to the table is thus not that BCAAs are not ergogenic. It's rather the previously overlooked leucine induced acceleration of the glucose alanine cycle in liver. It is the activation of this (catabolic!) powerhouse by the means of which leucine "might have an interesting use in physical performance in prolonged or submaximal exercise, where muscle glycogen stores are more likely to be depleted" (Campos-Ferraz. 2013). It should be noted, though, that these effects are probably only observed after the glycogen levels are fully depleted - after an intense workout, towards the end of a race or after an fasted training - in those situations, the performance benefits may even be more more significant than in the study at hand.

Reference:

• Campos-Ferraz PL, Bozza T, Nicastro H, Lancha AH Jr. Distinct effects of leucine or a mixture of the branched-chain amino acids (leucine, isoleucine, and valine) supplementation on resistance to fatigue, and muscle and liver-glycogen degradation, in trained rats. Nutrition. 2013 Nov-Dec;29(11-12):1388-94.
• Gualano AB, Bozza T, Lopes De Campos P, Roschel H, Dos Santos Costa A, Luiz Marquezi M, et al. Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. J Sports Med Phys Fitness 2011;51:82–8

The Dipeptide Advantage!? +43% Muscle Glycogen With Whey Hydrolysate Compared to Matched Amino Acid Mix

The bigger the choice, the harder it is to choose. If you had to pick just one, go for the concentrate, if you want to afford two, get an isolate or hydrolysate and a casein protein.

"Whey is still the way to go." I believe I wrote, or at least thought just that only a couple of days ago, when I wrote about the wheat gluten hydrolysate in the last installment of the SuppVersity Science Round Up Seconds (click here to read all previous installments). Unfortunately, there is not just one way... ah, pardon me, I do of course mean "whey", there are many! And in order to completely confuse their customers supplement companies will spike their concentrates, isolates and even hydrolysates with free form amino acids, or - which is even more confusing - advertise their BCAA and EAA products as being made from whey protein. I mean, who cares if the damn molecules are unbound and indistinguishable, anyway? But let's get to the point, a soon to be published study from Japan could yield at least some insights into demonstrable and purported benefits of one over the other.

Whey hydrolysate or simply its aminos, what gets pro-glycogen job done?

Based on results from previous experiments in the course of which the researchers had found that the acute provision carbohydrate + whey protein hydrolysate (WPH) had superior effects on muscle glycogen repletion compared to iso-nitrous amounts of BCAAs (Morifuji. 2010a) Kanda et al. speculated that chronic supplementation with whey protein hydrolysate (WPH) should elicit similarly beneficial effects and could help them clarify the underlying mechanism of this glycogen boosting effects of WPH. To this ends, the researchers put a group of mice on diets that differed only terms of the protein composition of the diet.

• 

  Table 1: Composition of the test diets

  The control group's exclusive protein source was the casein from the standard chow.
• The whey amino acid (WAA) group received a chow, where 50g of the casein protein was replaced by an iso-nitrogenous amount free amino acids that was matched to the amino acid composition of the whey hydrosolate.
• The whey hydrolysate group received 20% of the original casein from the standard chow in form of a whey hydrolysate from Meiji Co., Ltd.

In the course of the 4-week study period, body weight and food intake of the animals were measured on a weekly basis. The mRNA expression, protein levels, and phosphorylation of glycoregulatory enzymes were measured in the gastrocnemius muscle. All rodents performed a regular 30-min swimming exercise protocol  in a fancy adjustable-current water pool five times per week and had to 'survive' a weekly (endurance-)performance test in the course of which they had to swim to absolute failure (defined as being drowning for 7s, already).

Figure 1: Food intake, liver weight, and visceral fat (left), as well as time to total fatigue during swimming exercise (right) of the rodents on control, WAA and WPH diets  (data adapted from Kanda. 2012)

Contrary to the data from this test, the body composition markers in figure 1 do not show any significant inter-group differences (positive or negative) the same goes for the food intake and the liver weight, as well as for the total body weight of the mice, which was totally identical (not shown in figure 1). The said swimming performance of the WAA and WPH group, on the other hand, were 32% and 48% higher than in the control group.

More glycogen synthetase = more glycogen content = more endurance

Now, despite the fact that this increase did - for whatever reason - not reach statistical significance, Kanda et al. are convinced that this increase in endurance must be a direct consequence of the increase in glycogen storage, which has been observed by Evans and Hughes in 1985 (Evans. 1985), already, and has been confirmed numerous times thereafter.

Figure 2: Glycogen content and glycogen synthetase levels (GS), as well as mRNA expression of glycogen synthase I and the ratio of phosphorylated to unphosphorylated GS (data based on Kanda. 2012)

And, as you can see, the actual data in figure 2 clearly confirms this hypothesis. The mice who had received whey protein hydrolysate (WPH) in their diets for the whole 4-week study period had significantly (p < 0.05) higher muscle glycogen levels than their peers in the control group (73%) and still more than 40% more total glycogen than the mice who had been fed the amino acid enriched chow (WAA). Quite impressive, right? And all that is just a consequence of a peptide induced elevation in glycogen synthetase and it's activity, which is indicated by the lower ratio of phosphorylated (=incative) to un-phosphorylated (=active) levels of this tightly regulated enzyme.

There is more to whey than BCAAs

The total amount or activity of the glucose transporter (GLUT-4) as well as the hexokinase activity (which figures in the phosphorylation of sugars) were not different between treatments and though the dreaded gluconeogenesis in the liver was not measured it is, given the high amount of carbohydrates in the diets of the rodents, very unlikely that the higher susceptibility of "fast" protein sources to be oxidized, when no other nutrients are available, played a significant role in the 'pro-glycogenic' of whey hydrolysate (after all the rodents consumed the protein as part of their chow), so that the most likely explanation for the superiority of the whey protein hydrolysate over the iso-nitrous amino acid mixtures remains their peptide content. In this regards, the authors of the study remark:

"The amino acid compositions of the two diets used in this study contained equal amounts of BCAA and leucine; however, muscle glycogen accumulation varied between diets. This result strongly suggests that not only the BCAA content but also the molecular form of BCAA found in the protein source might be important for muscle glycogen storage." (Kanda. 2012)

Kanda et al. do then refer to a previous study, in which his group had been able to demonstrate that BCAA-containing peptides in WPH, which have been shown to be markedly elevated (meaning they are not digested) after the consumption of whey protein hydrolysates (Morifuji. 2010) in a follow up study on human beings, do actually have the ability to stimulate the rate of glucose uptake in vitro (Morifuji. 2009).

Figure 3: Insulin response after the ingestion of 12.5g of either soy or whey protein or their respective hydrolysates (Morifuji. 2010)

"And what about insulin?"

I know that this question is now on your minds and in way you are right the only slight caveat you have to keep in mind before you blindly follow the scientists' outspoken advice to consume "carbohydrates mixed with WPH[to] enhance sport performance by increasing glycogen storage" (Kanda. 2012) would in fact be be the increased insulin response. Of the latter, the scientists found in the aforementioned 2010 human trial (Morifuji. 2010) that it is ~70% more pronounced in the first hour after the the ingestion of 12.5mg of whey protein hydrolysate and, once more compared to regular whey protein, still ~17% higher over the whole 2h period (the different proteins you see in figure 3 were all ingested on an empty stomach after an overnight fast by the 10 normal-weight subjets; the data I mentioned refers to the AUC values on the bottom of figure 3).

The insulin 'spike' is not necessarily a problem. At the right time in the right person it can even be highly beneficial.

Nevertheless, the results of the study at hand to actually confirm that before you invest in all sorts of useless pills, it may make more sense to make sure that you a) have more than just a single protein powder in your supplement arsenal and that you b) have been reading enough SuppVersity articles to be able to use them properly ;-) ... What? You still don't know how? Well assuming you have no problems with high insulin levels and are mainly interested in building muscle, you could start out with 20-30g whey + 15-25g casein (depending on your body size and needs) after a workout (see "Whey & Casein Work Hand in Hand for Muscle Protein Anabolism") and a 40g casein shake pre-bed (see "3.2kg of Lean Mass Overnight").

By the whey *lol*, I suppose you will see similar benefits from a whey isolate, although this would have to be tested. What does not need any tests, on the other hand is that you better make sure you don't forget the carbs! I mean, what is your body supposed to use as a substrate for the increased glycogen synthetase activity, if you are depriving yourself of carbohydrates? The protein your liver converts to blood glucose? Yeah, what a glorious idea... whatare your brain and your other organs going to use then? Ketones? No way, if you are pounding tons of fast acting glucogenic amino acids in form of protein shakes.


References

• Evans, W. J.; Hughes, V. A. Dietary carbohydrates and endurance exercise. Am. J. Clin. Nutr.1985, 41 (5, Supplement), 1146−1154.
• Kanda A, Morifuji M, Fukasawa T, Koga J, Kanegae M, Kawanaka K, Higuchi M. Dietary Whey Protein Hydrolysates Increase Skeletal Muscle Glycogen Levels via Activation of Glycogen Synthase in Mice. J Agric Food Chem. 2012 Oct 31.
• Morifuji, M.; Koga, J.; Kawanaka, K.; Higuchi, M. Branched-chain amino acid-containing dipeptides, identified from whey protein hydrolysates, stimulate glucose uptake rate in L6 myotubes and isolated skeletal muscles. J. Nutr. Sci. Vitaminol. 2009, 55(1), 81−86.
• Morifuji, M.; Kanda, A.; Koga, J.; Kawanaka, K.; Higuchi, M. Post-exercise carbohydrate plus whey protein hydrolysates supple-mentation increases skeletal muscle glycogen level in rats.Amino Acids 2010a, 38(4), 1109−1115.
• Morifuji, M.; Ishizaka, M.; Baba, S.; Fukuda, K.; Matsumoto, H.; Koga, J.; Kanegae, M.; Higuchi, M. Comparison of different sources and degrees of hydrolysis of dietary protein: Effect on plasma amino acids, dipeptides, and insulin responses in human subjects. J. Agric. Food Chem. 2010b, 58(15), 8788−8797.

Glutamine, a Better Glucose Source Than Glucose? Can You (Ab-)Use It As an Intra-/Post Workout Supplement? Human Study Suggest: Yes You Can! 8g Will Do the Trick

Could it be better to use glutamine as the main energy source in an intra-workout beverage? Or is the latter superior to glucose, only when it's already to late, meaning only, when you already are hypoglycemic?

I see the irritation on your face. How on earth should glutamine be a better glucose source than glucose: Adel obviously has lost his mind under the pressure of putting out interesting stuff on a daily basis... well, while the latter may be true (how would a sane person do what I do?), I am actually just reformulating the main message of a recently conducted study from the State University of Maringá in Brazil. In the corresponding paper, which was published online in the International Journal of Endocrinology (Nunes Santiago. 2013).

So yes, glutamine is in fact the better glucose...or maybe I should clarify it is a superior source of glucose to promote glycemia recovery after insulin-induced hypoglycemia. In other words, it will help you to lose the dizziness, the tiredness, the shaking and the sweating that are only a handful of the symptoms of low blood sugar (=hypoglycemia) more readily than glucose.

How do the scientists know?

Actually Nunes Santiogo et al. tested not just glucose and glutamine, they also provided their rodents which had been injected with a non-lethal but profoundly hypoglycemic dose of 1U/kg insulin at the beginning of their experiment with either of these substances:

alanine
glutamine, or
saline (control group)
• glucose
• glycerol
• lactate

The dosage was identical (100mg/kg) for all of them, so that we had a "level playing field". Now, if I had not given away all the information right in the headline, you would probably have expected glucose to rule, right?

Figure 1: Glucose (mg/dl) levels after administration of 100mg/kg of saline, glucose (Glu), glycerol (Gly), lactat (Lac), Glutamine (Gln) or alanine (Ala) to hypoglycemic mice (Nunes Santiago. 2013)

What? Your money was on Lactate? Well that's actually a smart choice, as well and shows me that you have been attentive over the past months.

A note on lactate: In view of the results of a recent study that showed that lactate may not be able to completely replace glucose, but can modulate metabolic and neuronal activity in a way that the glucose contribution to brain metabolism under hypoglycemic conditions is restored to levels otherwise only observed at euglycemia (Herzog. 2013), it is likely that it could sooth the symptoms of hypoglycemia without even replenishing blood glucose to normal. Well, as long as it is buffered (NaHCO3 ;-) and is not converted to lactic acid, at least.

Yeah, lactate is an emergency fuel, so it does not seem totally unlikely that it works, but if you take a look at the study outcome in figure 1 you will realize that glutamine was not just a notch, but rather significantly more effective in getting the ~70% reduced glucose levels back up in the normal zone. It's also better than the #1 source of gluconeogenesis alanine, which in turn was still superior to "the real deal", i.e. glucose.

The glucose, diabetics, for example are so desperate to find ("Where's my Snickers?"), when they realize that they are about to go hypo after an insulin injection or workout, on the other hand, brought the levels back up to only 63% and was thus only slightly better than lactate of which I already hinted at in the box to the right that the actual blood sugar levels may not adequately reflect the symptoms, due to it's ability to modulate the energy flux to the brain.

How could that be? Why is glutamine more effective than glucose?

It still sounds odd, I know, so let's see what the scientists have to say about their own results:

"In contrast with rats, oral glutamine showed better glycemia recovery compared with alanine (Figure 1). This difference could be attributed to the possibility that in mice the catabolism of glutamine in the enterocytes is lower than in rats" (Nunes Santiago. 2013)

Now this is a problem, because it makes the usual question of whether or not these results apply to human beings, or not even more difficult to answer. Are we more like rats or rather like mice? And what would be the perfect "blood sugar restoration agent" for us - Glucose or glutamine. I honestly cannot answer this question, but I can still give you a decent bottom line, I guess.

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Suggested read: "Post-Workout Glycogen Repletion - The Role of Protein, Leucine, Phenylalanine and Insulin. Plus: Protein & Carbs How Much do You Actually Need After a Workout?" | read more

Bottom line: Irrespective of whether it is "optimal" it is certainly a viable way to keep your glucose up and even replenish your glycogen levels after a workout by supplementing with l-glutamine. In 2005, for example, Iwashita et al. were able to show that 8g of glutamine promote storage of muscle glycogen to an extent similar to 330ml of 8.5% (wt/vol) glucose polymer solution (Bowtell. 1999); and this would not work if the glutamine was not turned into glucose by the liver and transported to the muscle in the blood stream so that it will - at least for as long as it disappeared in the skeletal muscle glycogen stores - also be available for the brain, the heart and all the other organs.


Whether things look different in insulin induced hyperglycemia is questionable, but I tend to think that 99% of you are interested in it's use as a workout / post-workout fuel in exchange for carbs and not so much as a means to save your life, when you you've been overdoing your slin shots.

If that's what you want to do, the optimal strategy would be to combine both. According to Bowtell et al. this will increase the non-oxidative glucose disposal by another +25%. This would also have the advantage that you are not overtaxing the glyconeogenic pathway in the liver. A potential overload of the latter is by the way also the reason why I strongly advise against trying to live off glutamine let alone other not as readily metabolized amino acids as your sole source of glucose (or energy in general).

Additional reads:

• "30g of oral glutamine have similar effects on GLP-1 as 75g of glucose" | read more
• "7 Rarely Thought of Side Effects of High Dose Glutamine" | read more
• "Chronic High Dose BCAA Supplementation Reduces Endurance Performance by 43% Plus: How Ammonia, Glutamine, Arginine & Low Carb Could be Involved" | read more
• "New Role for Glutamine in Protein Synthesis? Study Suggests Direct Effects on Mammalian Target of Rapamycin (mTOR) - EAAs Alone Won't Produce Optimal Results" | read more
• "Use Glutamine to Heal the Gut and Hinder Your Gut Bacteria from Eating Away Your BCAA, Arginine and Other Aminos" | read more

References: 

• Bowtell JL, Gelly K, Jackman ML, Patel A, Simeoni M, Rennie MJ. Effect of oral glutamine on whole body carbohydrate storage during recovery from exhaustive exercise. J Appl Physiol. 1999 Jun;86(6):1770-7.
• Herzog RI, Jiang L, Herman P, Zhao C, Sanganahalli BG, Mason GF, Hyder F, Rothman DL, Sherwin RS, Behar KL. Lactate preserves neuronal metabolism and function following antecedent recurrent hypoglycemia. J Clin Invest. 2013 May 1;123(5):1988-98. 
• Nunes Santiago A, Ferreira de Godoi-Gazola VA, Milani MF, et al. Oral Glutamine Is Superior Than Oral Glucose to Promote Glycemia Recovery in Mice Submitted to Insulin-Induced Hypoglycemia. International Journal of Endocrinology, vol. 2013, Article ID 841514, 7 pages, 2013.

Well-Stocked Muscle Glycogen Stores Not Necessary For Exercise Induced Muscle Anabolic Response. Additional 5x Increment by Post(!)-Workout Whey + Cho Supplement.

Image 1: Glycogen depleted or not,
post-workout protein, preferably from a 
leucine-rich, fast digesting and nutritionally
complete source such as whey, is a must.

It is one thing that many trainees feel they perform better, train harder or have better endurance, when they (over-)"load" their muscle glycogen stores pre-workout. And as long as their need for carbohydrates is not merely imaginary, i.e. they feel sluggish and their gym performance sucks, whenever they are training on empty glycogen stores, I am quite sure that they will also make better gains. This mechanism would yet be completely different from any immediate, yet hitherto scientifically not validated, facilitative biomolecular effect of well-stocked glycogen stores on muscular hypertrophy, as it is proposed by many advocates of preworkout or even 24/7 carbohydrate (re-)feeding.

Dr. Connelly, who talked about this issue at length in the past installments of the BodyRX Show, was kind enough to remind me that back in 2007 Coffey et al. from Stuart Phillips' group at McMaster University, in Hamilton, Ontario (Canada), conducted a study that was based on an antithetical hypothesis, i.e. whether or not commencing resistance exercise with low muscle glycogen would enhance the encoding of genes implicated in muscular hypertrophy (Coffey. 2007). Yet, while there were significant differences at rest for the glycogen depleted vs. the normal leg of the subjects, both the increased GLUT4-MRNA expression, which is a sign of an increased capacity for glucose uptake, as well as the reduced expression of atrophic atrogenes (responsible for proteolysis, i.e. protein degradation) were overridden by exercise. Now, four years later Donny Camera from the University of Melbourne presented the results of a recent colloberation with the scientists from McMaster at the American College of Sports Medicine Conference in Denver, this year (Camera. 2011). The intention of this 2nd study was to elucidate the "effect of divergent glycogen content and subsequent post-exercise nutrition on anabolic signaling target p70S6 kinase during the early recovery period" after the completion of a standardized resistance training protocol.

Illustration 1: Very simplified illustration
of the role of mTOR and p90S6K
in protein synthesis.

Did you know that p70S6 kinase is a key component of the mTOR (the mammalian target of rapamycin) signaling cascade? The activation of mTOR via branched chain amino acids (leucine in particular) has been shown to increase p70S6K phosphorylation (the phosphorylation is equivalent to 'switching' it on). In a similar vein, physical exercise can activate protein synthesis via phosphorylation (activation) of p70S6K. The degree / increase / decrease of p70S6K kinase phosphorylation is thus considered a reliable indicator of the protein anabolic response to supplement and exercise protocols.

The evening before the actual experiment was conducted, the 16 resistance-trained male subjects (~23y) who participated in the study, reported to the laboratory in order to perform a single-legged cycling exercise to fatigue. In order not to upset the thusly established difference in glyocogen content between the trained (LOW) and the untrained leg (NORMAL), the subjects consumed an identical low carbohydrate meal after the workout and had to abstain from foods until the subsequent day, when they performed 5 unilateral leg press repetitions at 80% of their personal 1RM (one-repetition-max) with both their normal, as well as the glycogen depleted (LOW) leg. Muscle biopsies were taken 1h post exercise, and subjects consumed either a 0.5l post-workout shake that consisted of 20g whey + 40g maltodextrin or placebo immediately post and 2h after the exercise regimen.

Figure 1: Increase in  p70S6K phosphorylation in 16 resistance trained males after unilateral leg press exercise in normal and glycogen depleted leg relative to baseline (data adapted from Camera. 2011)

Although the muscle glycogen content increased exclusively in the nutrient (20g whey + 40g maltodextrin) group, significant increases of phosphorylation of p70S6K one of the key regulators of protein synthesis were seen in both legs of the subjects. As my plot of the restricted data I could extract from the abstract in the conference protocol (a paper obviously has not been published, yet) indicates, this increase was augmented up to 5x in the 1-4h hour post workout window in the glycogen depleted leg. While there was still a 8x increase in p70S6K phosphorylation in the glycogen-depleted leg even in the absence of post-workout nutrient repletion, post-workout nutrient (re-)feeding turned out to be necessary to illicit any increase in p70S6K phosphorylation over baseline in the normal leg.

Note that the baseline levels of the LOW and the NORMAL leg were probably different and the 8x increase could thus have lead to an absolute level of p70S6K phosphorylation that was still lower than in the NORMAL leg..

These results do not only contradict the initially raised hypothesis that well-stocked glycogen stores would be a necessary or at least facilitative prerequisite for the muscle anabolic response to exercise to take place, they also (re-)raise the question whether "training on empty" may not after all be advantageous if ...

1. the training performance is not effected by the lack of muscle glycogen and
2. the muscle anabolic response is augmented via appropriate post-workout nutrient-replenishment

Since this conjecture is yet solely based on the relative increases in phosphorylation, the scientists cite in their abstract, it is far from being a valid scientific hypothesis. We will probably have to wait for the publication of a respective paper (or ask someone who was lucky enough to attend the presentation for the absolute values; cf. "Note...", above), to get a preliminary answer on any beneficial effect exercising in a glycogen depleted state could have. In that, I would like to add that its artificial incarnation, i.e. the induction of local glycogen depletion, as it was practiced in the study at hand, has no significance with regard to the whole body (including liver) glycogen depletion some trainees experience as a result of (over-)training and no-carb (over-)dieting. In case of the latter, it does not take a rocket scientist to be able to tell that this won't have any beneficial effect on the gains people are making in the gym.

Melatonin the Anabolic On-Switch!? Is Supplementation Necessary for Older and Beneficial for Younger Trainees?

Whatever sleeping position you and your partner prefer, you better make sure you do get some sleep. There'll still be time for life's other pleasures, don't worry  ;-)

If you are - as I would highly suggest - following the 6-12 SuppVersity Short News on Facebook, you will be aware of the accumulating evidence suggesting that a lower resistance to the inflammatory assault of exercise is at the heart of the age-induced decline in muscle gains.

We all know that especially those of us, who are still in good shape in their 60s and beyond are already having a hard time to keep the status quo, and only a handful of them appears to be able to make constant progress. But is this something you just have to accept or can the latest research help you overcome or at least lower the "anabolic" resistance? And if so, could young(er) individuals benefit from the same or similar interventions?

Age, inflammation, recovery and supercompensation

In a soon-to-be-published study from the University of Alabama at Birmingham an analysis of the vastus lateralis muscle gene expression and protein cell signaling of the IL-6 and TNF-α pathways in myoblasts from young (AGE28) and old (AGE64) donors, which have been pre-treated with TNF-α revealed that ...

"[i]ndices of activation for the pro-inflammatory transcription factors STAT3 and NFκB were highest in AGE76. Resistance loading reduced gene expression of IL-6 receptor, MuRF1, and atrogin-1, and increased TWEAK receptor expression. Donor myoblasts from AGE64 showed impaired differentiation and fusion in standard media, and greater NFκB activation in response to TNF-α treatment (compared to AGE28)".(Meritt. 2013; you know it already, if you are following www.facebook.com/SuppVersity)

These findings show for the first time that the aging process alone is associated with a hightened susceptibility to muscle inflammation.

Graphical illustration of what you should have learned by now, if you read the previous installments of the Intermittent Thoughts; note: while I have used the arrows rather indiscriminately (they do not necessary mean "causes"), the stops at the end of other lines indicate an inhibition, eg. the line from exercise to myostatin indicates that exercise inhibits myostatin, which would inhibit increases in myonuclear domain sizes, if it was not "switched off" by exercise... (learn more)

In view of the importance of "controlled inflammation" in the context of muscle damage, repair and supercompensation (learn more in the Intermittent Thoughts on Muscle Building, spec. this episode), the goal should thus be to (a) lower the inflammatory load to a level that allows the aging body to cope with it and (b) improve your body's ability to cope with a certain (yet to be determined) amount of inflammation that's necessary for the hormetic response to exercise to take place.

As alluded to in the introduction to this article, the same 500mg+ of vitamin C + 400IU+ of mixed tocopherols per day that are - at best - useless for a young trainee could in fact make a smart and valuable addition to the supplement stack of an older physical culturist, who is more reliant on exogenous ROS scavengers than the young grasshopper, for whom the exercise-induced inflammation is part of the training: A training for his endogenous defense system and a potential prerequisite for the structural remodeling process of the muscle (check out the figure on the right and learn more).

Melatonin: Protection beyond ROS scavenging

At least for the well-educated SuppVersity student you are ;-) It should be obvious that the "classic" anti-oxidants like vitamin C and E are not the only venues molecules to control inflammation. In fact, the emerging science shows that alternatives to these "Kamikaze"-inhibitors (ROS scavengers) can, in this, as well as other contexts, deliver much better results.

As a SuppVersity reader you'll know that melatonin is also an Alzheimer protectant, can help you shed body fat, could be the goto-supplement for ultra-marathon runners, figures in the cardio-protective and controls the circadian rhythm, the disturbance of which is involved in "all things bad" ranging from metabolic syndrome over diabetes to cancer.

Think of DHEA, for example. The adrenal hormone, which happens to decrease from year to year once you've passed your late 20s can even help young men to cope with the muscle damage of 5 days of concomitant combined endurance, strength and HIIT training in young men (read the whole story).

Or - and now we are finally zoning in on the actual news - think of melatonin, which has been shown to boost your anti-oxidant defenses, reduce the oxidaton of the lipids in your cell walls and modulate the immune response to intensive training, when it is supplemented in relatively high amounts of 6mg (learn more; don't forget to check out the links in the infobox to the right, as well).

It will therefore only come as a minor surprise for a diligent SuppVersity reader like yourself that a recent rodent study that has just been accepted for publicaton in the Journal of Pineal Research comes to the conclusion that..

[...a]dequate levels of circulating melatonin are [...] necessary to improve energetic metabolism efficiency, reducing body weight and increasing insulin sensitivity [in aging animals]. (Mendes. 2013)

Ah, and just to make that clear, I am not willing to start the "mice are no little men"-debate, here, but will take it for granted that you keep in mind that results, I have plotted for you in figure 1 have to be verified in future human trials (personally, I am confident, they will).

Figure 1: Relative levels of visceral fat, triglycerides, change in distance covered from month 0-2, running speed, citrate synthase activity, muscle & liver glycogen and glucose AUC during tolerance test; all data expressed relative to sedentary (S-) unsupplemented (-C) control, SC (Mendes. 2013)

So what are we seeing here in figure 1? Well, first of all there is a surprisingly significant (compared to the SC group) decrease of total, but more importantly visceral fat weight in both, the sedentary (SM), as well as the trained (TM) rodents. The latter goes hand in hand with

• 

  Expression of the muscle anabolic enzymes PI3K, p-AKT, as well as AMPK and GLUT4 in muscles of the supplemented (SM & TM) and non-supplemented (SC & TC) rodents in arbitrary units (Mendes.2013)

  significant improvements of the amount of triglycerides (a if not the no1 risk factor for CHD) even in the absence of exercise (compare the SC vs. SM groups)
• a mind boggling increase in the distance covered and the running speed of the animals in both the trained and the sedentary rodents "on" melatonin (in view of the fact that this increase remains statistically significant even when you compare it to the baseline levels, similar effects may even occur in young animals)
• almost 3x respectively 4x elevations in citrate synthase activity, a maker of fatty acid oxidation in the sedentary and trained melatonin treated rodents
• a 6x and 12x increase in muscle glycogen levels and an ameliorative effect on the exercise induced glycogen increase in the liver, both of which could not just explain the massive increase in exercise tolerance, but the previously observed beneficial effects on glucose tolerance, as well
• a 30-40% reduction in the glucose AUC that corresponds with the increased glycogen storage mentioned in the previous bulletin point

and lastly and for many of the physical culturists in the posterior half of their lives maybe most importantly, highly significant increases in the activity of the pro-anabolic PI3K, MAPK and AKT that were not increased at the expense of the fat-burning, anti-cancer, anti-diabetes AMPK energy switch (see figure 2).

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Bottom line: It is beyond doubt that the small amount of exercise corresponding to the four to five sessions at 0.3 – 0.5 km/h running on a 0% grade treadmill [questionable whether this is a typo on the speed, by the way] for 10 min/day in the study at hand alone are good for aging individuals. It's also almost certain that the addition of supplemental melatonin ameliorates these exercise-induced benefits and induce benefits on their own.

Don't forget t take appropriate time off, otherwise even 15g of melatonin are not going to help you overcome a growth plateau. Why? Well "Chronic Resistance Training Reduces the Anabolic Signaling in Response to Exercise - 12 Days of Detraining Restore It" (read more)

What is yet highly questionable still is the optimal dosage. The 1mg/kg body weight that were used in the study at hand would translate to roughly 0.16mg per kg for a human being and thus ~13mg for an adult (male) human being. Personally, I don't think this is exorbitantly high, but I know that real and pseudo-experts would be bashing me, if I even remotely suggested that you consume similar as much supplemental melatonin on a regular basis... what all of us would probably agree on is the fact that future human studies are necessary, and if you asked me not so much to avoid potential harm, but rather not to miss what Mendes et al. believe would be an outstanding chance to "improve the beneficial responses induced by regular exercise in aging individuals, promoting a better quality of life and a healthier aging process" (Mendes. 2013).

 References:

• Mendes C, de Souza Lopes AM, Gaspar do Amaral F, Peliciari-Garcia RA, de Oliveira Turati A, Massao Hirabara S, Scialfa Falcão JH, Cipolla-Neto J. Adaptations Of The Aging Animal To Exercise: Role Of Daily Supplementation With Melatonin. Journal of Pineal Research. 2013 [accepted manuscript]
• Merritt EK, Stec MJ, Thalacker-Mercer A, Windham ST, Cross JM, Shelley DP, Tuggle SC, Kosek DJ, Kim JS, Bamman MM. Heightened muscle inflammation susceptibility may impair regenerative capacity in aging humans. J Appl Physiol. 2013 May 16.

Amino Acid Supplement With High Amount of Isoleucine Increases Clearance of Dextrose Supplement, But Impairs Post-Workout Glycogen Resynthesis in Man - Implications?

Post-Workout High Isoleucine AA+CHO Decreases Glucose Spikes, But Impairs Musclular Glyocogen Resynthesis - Reason Enough to Skip Amino Acids?

If you put any faith into the promises of the supplement industry, amino acid supplements are the solution to all your problems - including those you haven't even known about, yet. Against that background it's always interesting if scientists study the real world effects of amino acid supplements in a realistic scenario like after strenuous exercise.

In their latest study Wang and colleagues from the University of Texas at Austin and the Shanghai Research Institute of Sports Science did just that: They studied the effects isoleucine and four additional amino acids, on blood glucose homeostasis and glycogen synthesis after strenuous exercise.

Learn more about amino acid and BCAA supplements at the SuppVersity

Glutamine Helps W/ Diabetes

Whey + Casein Beat GLU + BCAA

Alanyl-Glutamine is it any good?

GLU for Glycogen Repletion?

GLU as Intra-Workout BV?

BCAAs deplete neurotransmitters

As the scientists point out, the results of their study "could provide a practical and safe means of increasing the rate of muscle glycogen synthesis after exercise and enhancing the rate of recovery" (Wang. 2015).

Table 1:  Subjects’ characteristics (Wang. 2015).

Ten healthy active adults volunteered for the study. All subjects were accustomed to cycling for prolonged periods of 3–5 h during an exercise session. The ,aximum oxygen uptake (VO2max) was measured in all subjects on a cycle ergometer by using a TrueOne 2400 metabolic measurement system (ParvoMedics, Sandy, Utah) to verify adequate aerobic fitness levels (results see Table 1).

Figure 1: Basically the AA supplement contained almost exclusively isoleucine. It was administered in the dosage shown above and at twice that amount in the LAA and HAA trials (Wang. 2015)

"Two to three days after the VO2max test, the subjects reported to the laboratory to perform a practice ride to familiarize them with the laboratory environment and the experimental protocol. The practice ride was also used to adjust and verify appropriate workloads for the experimental trials. The practice rides simulated the protocol ride but without blood samples or muscle biopsies being taken. The ride consisted of cycling at 70 % VO2max for 2 h, which was followed by five 1-min sprints at 85 % VO2max. The sprints were separated by 1 min cycling at 45 % VO2max. During the first 15 min of each hour, oxygen uptake was measured for 5 min to verify workload.

Water (250 mL) was provided every 20 min of exercise. Heart rate (HR) was monitored and ratings of perceived exertion (RPE) on a Borg-scale (ranging from 6 to 20) were collected every 30 min of exercise. The practice ride and each of the following three experimental trials were separated by a minimum of 7 days and maximum of 12 days" (Wang. 2015).

The actual tests consisted of cycling on an ergometer to deplete muscle glycogen. Blood sampling and a muscle biopsy were performed immediately on cessation of exercise. After the muscle biopsy, subjects were given the first of two supplement doses. More specifically they received either...

• 1.2 g carbohydrate/kg body weight (CHO), 1.2 g carbohydrate/kg body weight plus 6.5 g AA (CHO/LAA) or 
• the same carbohydrate supplement plus 6.5g (CHO/LAA) or 13 g AA (CHO/HAA) 

immediately after the first muscle biopsy and at 120 min of recovery. The carbohydrate base consisted of simple dextrose dissolved at a ratio of 100g/296 mL in an orange flavored drink (SUN-DEX, Fisher Healthcare, Houston, Texas). The additional amino acids contained 0.046 g cystine 2HCl, 0.023 g methionine, 0.045 g valine, 6.342 g Isoleucine, and 0.044 g leucine per person, or twice that amount in the CHO/HAA trial. The amino acids were simply added to the dextrose drink.

Why would you even believe that there may be benefits from AA supplementation?

As Wang et al. point out, "this amino acid mixture was selected as it was previously reported to be more effective in lowering the blood glucose response to a glucose challenge than isoleucine alone" (Wang. 2015) by Bernard et al. (2011).

Figure 2: Blood glucose AUC during the oral glucose tolerance test (OGTT). Sprague-Dawley rats were gavaged with either glucose (CHO), glucose plus a 5-amino acid mixture (CHO-AA-1), glucose plus a 5-amino acid mixture with increased leucine concentration (CHO-AA-2), or placebo (PLA). Blood was taken from the tail immediately before the gavage and 15, 30, 60, and 120 min afterward (Bernard. 2011).

The three test beverages were similar in color, taste, and texture to allow a double-blinded and counter-balanced study design. All test drinks were randomly assigned and dispensed by a laboratory technician who was not involved in the data collection.

Figure 3: Blood glucose postexercise and during the 4-h recovery. Treatments were with CHO (circle), CHO/LAA (triangle), and CHO/HAA (filled circle) supplements provided immediately after and 2 h after exercise. Values are mean ± SE. CHO/HAA vs. CHO (*p < 0.05). CHO/LAA vs. CHO (# p < 0.05) - left; Blood glucose area under the curve (AUC) during the 4-h recovery. Treatments were CHO, CHO/LAA, and CHO/HAA supplements provided immediately after and 2 h after exercise. AUC was calculated with baseline (pre). Values are mean ± SE. CHO/HAA vs. CHO (*p < 0.05). CHO/LAA vs. CHO (# p < 0.05) - right (Wang. 2015).

As the data in Figure 3 indicates,There was a similar effect in humans as it has previously been observed in rodents. An effect of which you as a SuppVersity reader know that it is probably mostly ascribable to isoleucine (see "The Glucose-Repartitioning Effects of Isoleucine" | more).

Glucose modulation without glycogen optimization?! How does that work? Well, obviously glucose can also be oxidized or used to replete ATP in the muscle. It is at least no real news that isoleucine will decrease glucose levels in the blood and increase glucose uptake in the muscle without, however, producing increased glycogen levels. For example, Doi et al. (2005) reported that an oral administration of 1.35 g/kg isoleucine in food-deprived rats significantly decreased the plasma glucose concentration and increased glucose uptake in the muscle of rats without an increase in muscle glycogen storage.

Figure 4: Total muscle glycogen storage in the vastus lateralis during the 4-h recovery from intense cycling. Treatments were CHO, CHO/LAA, and CHO/HAA supplements provided immediately after and 2 h after exercise. Values are mean ± SE. CHO/HAA vs. CHO (*p < 0.05 | Wang. 2015)

What is a bit disappointing is the fact that the decrease in blood glucose did not come with an increase in glycogen storage.

As the data in Figure 4 shows, the exact opposite was the case. After 4h of recovery the muscle glycogen levels were not higher, but lower in the amino acid supplemented trials.

For diabetics this wouldn't be a problem. For athletes it's yet clearly a disadvantage that the 4-g recovery glycogen levels were lower and significantly lower in the low and high dose amino acid supplement trials.

Eventually this result is surprising because specifically in the high amino acid group (a) the insulin levels, (b) the AS160, a protein that controls insulin mediated glucose uptake, (c) the mTOR & p-AKT levels, (d) the "exercise hormon" levels of serum irisin  and (e) the levels of glycogen synthase which stores carbs in forms of glycogen in the high dose AA trials were significantly elevated.

Bottom line: While the study at hand did confirm that isoleucine (in conjunctio with other, but probably irrelevant amino acids) will improve the glucose response to high GI carbohydrates, it did not confirm the assumption that this makes isoleucine the ideal intra- and/or post-workout amino acid to optimize glycogen synthesis and thus post-workout recovery. For diabetics the increase in insulin and the corresponding decrease in glucose response still is a major plus. This assumes that the insulin increase occurs in the obese (in previous studies by Wang et al. (2012) an increased insulin release to a high isoleucine AA mixture was not observed) and / or that there is an independent effect of the amino acid mixture on glucose uptake in the muscle or the periphery.

In contrast to the high isoleucine amino acid supplement that was used in the study at hand, plain whey protein does increase glycogen storage after workouts - significantly, as the data Ivy et al. generated in a 2004 randomized controlled human study involving well-conditioned subjects observed (Ivy. 2004).

For athletes, however, it appears to be detrimental as it reduces the rate of muscle glycogen synthesis after workouts and puts a questionmark behind the "repartitioning effects" of amino acids - if there is a repartitioning effect involved, here, it would be away from the glyocogen stores of your muscle. An effect that may be related to the increase in mTOR which triggers protein synthesis via p70S6k which inactivates the glycogen synthase kinase-3 (Armstrong. 2001). This would indicate that you cannot have both maximal protein & glycogen synthesis and thus relativize the obvious conclusion that isoleucine supplements are not suitable for athletes. What it won't do, though, is to provide the missing evidence that amino acid supplements have an advantage over whey, which has been shown to increase glycogen synthesis and storage (Morifuji. 2005, 2010; Zawadzki. 1992; Ivy. 2002, 2008) - why would you use AAs, then? | Comment on Facebook!

References:

• Armstrong, Jane L., et al. "Regulation of glycogen synthesis by amino acids in cultured human muscle cells." Journal of biological Chemistry 276.2 (2001): 952-956.
• Bernard, Jeffrey R., et al. "An amino acid mixture improves glucose tolerance and insulin signaling in Sprague-Dawley rats." American Journal of Physiology-Endocrinology and Metabolism 300.4 (2011): E752-E760.
• Doi, Masako, et al. "Isoleucine, a potent plasma glucose-lowering amino acid, stimulates glucose uptake in C2C12 myotubes." Biochemical and biophysical research communications 312.4 (2003): 1111-1117. 
• Ivy, John L., et al. "Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement." Journal of Applied Physiology 93.4 (2002): 1337-1344.
• Ivy, J. L., et al. "Post exercise carbohydrate–protein supplementation: phosphorylation of muscle proteins involved in glycogen synthesis and protein translation." Amino acids 35.1 (2008): 89-97.
• Morifuji, Masashi, et al. "Dietary whey protein increases liver and skeletal muscle glycogen levels in exercise-trained rats." British journal of nutrition 93.04 (2005): 439-445.
• Morifuji, Masashi, et al. "Post-exercise carbohydrate plus whey protein hydrolysates supplementation increases skeletal muscle glycogen level in rats." Amino acids 38.4 (2010): 1109-1115.
• Wang, Bei, et al. "Amino acid mixture acutely improves the glucose tolerance of healthy overweight adults." Nutrition Research 32.1 (2012): 30-38.
• Zawadzki, K. M., B. B. Yaspelkis, and J. L. Ivy. "Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise." J Appl Physiol 72.5 (1992): 1854-9.