Forskolin: Friend or Foe? Stories and Studies About Fat Loss, Lean Gains, Topical Cellulite Treatment, Testosterone, Cancer, Hepatotoxicity, Drug Interactions & More

There is a single human study that would suggest that forskolin would make you get closer to this classic physique w/out tons of salad (who said that's necessary anyway?).

Since Maxim asked in one of his more recent comments about the usefulness and/or downsides of forskolin, I dediced to dedicate this Sunday (finally again?) to answering a user question and am going to briefly sum up some older and the few novel findings on forskolin I am aware of.

For those of you who find that boring: Don't blame Maxim alone, another reason for this decision was that I have seen discussions on forskolin resurface elsewhere on the Internet. By the way, I write re-surfaced, because forskolin has once been hailed as a testbooster and fat loss adjuvant, but as the prices increased and people came out with faked or low-quality products that did not yield results, the market collapsed.

What is forskolin and where does it originate from?

As usually there is more than a single answer to this question. The most straight forward general ones are probably (a) it is a white to white with yellow cast powder, or (b) a labdane diterpenoid with antihypertensive, positive inotropic, platelet aggregation inhibitory and adenylate cyclase activating properties. Moreover, forskolin is able to activate the adenylate cyclase and thus increase the intracellular cyclic AMP levels in most tissues and cells. And hat  it's called forskolin, because it is derived from the Indiant plan Coleus forskohlii is probably something 99% of you knew already.

The reason I suppose that Maxim got interested in it, is that it is commonly used in cell studies to raise the levels of cyclic AMP (cAMP; cf. Alasbahi. 2012) and did a pretty impressive job in the recently discussed PGC-1a study. On the other hand, it did also increase the expression of the aromatase enzyme in the Yang study mentioned in the "Natural Sildenafil & Testosterone Alternative" post on which Maxim replied with the initially mentioned comment.

"Wait, wasn't it supposed to be a testbooster and now it also inhibits myostatin and increases estrogen? What does this stuff not do?" - Well, forskolin is, above all, a cAMP modulator

Forskolins chemical structure. Sometimes it's also referred to as Colforsin; 7-beta-acetoxy-8, 13-epoxy-1-alpha, 6-beta, 9-alpha-trihydroxylabd-14-en-11-one; or Coleonol (img. from Sigma-Aldrich's product database)

I know that sounds confusing, but in essence forskolin does nothing but increasing cAMP levels in almost all types of cells. cAMP a breakdown product of ATP (=> cAMP => AMP) in turn is one of those molecules which exert most their effects as intracellular signal transducer. In that, it is involved in the activation of protein kinases and regulates the effects of adrenaline and glucagon. It also modulates the calcium channels and contributes to growth hormone release; unfortunately, cAMP has also been implicated in the proliferation of not very beneficial cell growth aka cancer. The same ion-flux mediation has recently been implicated in the etiology of ADHD, as well (Arnsten. 2012).

Still, it's not all about c-AMP. Probably cAMP unrelated downsides of coleus forkohlii are for example:

• forskolin induces hepatic CYP2C enzymes and coleus forskohlii extract and thus attenuates the anticoagulant action of warfarin. (Yokotan. 2012) 
• even more than isolated forskolin, coleus forskohlii  messes with the hepatic enzyme cascade (P450) and has even been shown to be hepatoxic in a study published in the July issue of the Journal of Toxicology (Virgona. 2012)

On the other hand there are a handful of benefits, e.g.

• 

  Figure 1: Effects of 12 weeks on 2x250mg (10%) forskolin on testosterone (free and total) and lean & fat mass (Godard. 2005)

  In a 2005 study (Godard. 2005), which caused quite a stir in the health and fitness community back then, Godard et al. observed profound beneficial effects of testosterone and body composition (cf. figure 1) after the ingestion of 2x250mg of a 10% standardized forskolin (Forslean).
  
  Now, the unfortunate truth is that the15 subjects (average age, BMI, and body fat percent were 24.4 +/- 5.9 years, 32.5 +/- 4.1 kg/m2 , and 35.2 +/- 8.3%) who had been randomized to the active arm of the study, and the 15 participants in the placebo arm (28.7 +/- 8.6 years, 32.6 +/- 3.8 kg/m2 , and 35.0 +/- 7.3%) were non-active sedentary overweight/obese (BMI 26 kg/m2 or more) individuals. Add the funding by Sabinsa (Forslean producer) to the equation and decide for yourself how relevant you think the results are going to be for you...

• In several in-vitro studies, forskolin has been used as a positive control to compare the effects of other compounds on the testosterone release in leydig cells. Lin et al. for example used it in 2001 as a comparison for lactate and found a ~3x increase in testosterone release in incubated leydig cells (Lin. 2001). A similar study by Yu et al. showed that the addition of green tea catechins lead to an additional stimulation of forskolin induced testosterone production in cell cultures (Yu. 2010).

• 

  Figure 2: Results of 12-week intervention w/ forskolin containing topical cream (Roure. 2011)

  As part of a topical cosmetic slimming product combining tetrahydroxypropyl ethylenediamine, caffeine, carnitine, retinol and, obviously, forskolin it has shown some promise as a topical anti-cellulite and toning agent (Roure. 2011). The clinical study was however financed by Johnson & Johnson and I am not sure how much of the effects were actually brought about by forskolin (the placebo was a basic gel with the same texture containing mainly water, gelifying and preservative systems). So take the data in figure 2 with a grain of salt, ladies - I bet 12 weeks on this product are not going to be exactly inexpensive.

• The administration of forskolin in conjunction with rutin (the glycoside between the flavonol quercetin and the disaccharide rutinose), vitamin B1 & B2 in a 2010 study by Pescosolido et. al. lead to a significant reduction in intra-ocular pressure in 15 glaucoma patients after 40 days (Pescosolido. 2010). Similar results were observed in a 2012 study for forskolin and rutin alone (Vetrugno. 2012)

• An in-vitro study by Cristobal et al. provides first evidence for the ability of forskolin to restore PPA2 in acute myeloid leukemia. That would make it a potential candidate for the treatment of this type of cancer, but to my knowledge there is as of yet not even a rodent study that would support these in-vitro results. Moreover, previous studies have suggested that Forskolin may even favor the proliferation of other types of leukemia (Kobayashi. 1994)

Time to weigh the "established" benefits and downsides

Figure 3: Effect of different doses of forskolin with and w/out epinephrine on FFA release from rat adipocytes - watch out this is from yet another in-vitro study with rodent cells (Litosch. 1982)

 In view of the fact that the aforementioned study by Godard is the only human study is only backed up by in-vitro data from rodent studies (Litosch. 1982, cf. figure 3), the fat loss benefits are as  Jeukendrup et al. point out in their 2011 review of purported fat burners...

"[...] promising, there is [yet] only one study at the present time and more work is required before forskolin can be recommended as a fat metabolism-enhancing substance." (Jeukendrup. 2011)

If you add to this the host of wanted and unwanted, known and unknown side effects that occur in response to the coleus foskohlii induced cytochrome P450 modulation (e.g. the mice in the aforementioned study by Virgona lost some visceral fat, but the costs were increased fat deposition in the liver and elevated transaminase levels).

With the questionable "fat loss" benefits (remember stress is also a powerful lypolitic and the problem is not to get the fat out of the cell, but rather to burn it), and the almost non-existant human data on the purported testosterone boosting effects, this should be reason enough not to buy more than one bottle for a test-run. After which I highly suggest to do some lab work to see if whatever good or bad you believe you are feeling is an actual boost in T (check T-levels) or hepatic side effects (check ALT, AST & ALP).

Note (update in response to comments): As far as the hepatoxicity is concerned the suggested dosage of 2x 250mg coleus forskholii most supplements come with may be higher than the medium dose in the study by Virgona, but is still probably "liver save" if you double dose on that, you are however landing in the no-man's land (=not tested for) gray zone between the medium dosage and the "danger zone" of  ~49mg/kg per day (human dose equivalent) that was tested in the study. Don't freak out, if you did that in the past, the levels return to normal afterwards and temporarily elevated ALT + AST or ALP levels do not necessarily mean that your liver is whacked forever ;-)

References:

• Alasbahi RH, Melzig MF. Forskolin and derivatives as tools for studying the role of cAMP. Pharmazie. 2012 Jan;67(1):5-13.
• Arnsten AF, Jin LE. Guanfacine for the treatment of cognitive disorders: a century of discoveries at Yale. Yale J Biol Med. 2012 Mar;85(1):45-58. Epub 2012 Mar 29.
• Godard MP, Johnson BA, Richmond SR. Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese men. Obes Res. 2005 Aug;13(8):1335-43. 
• Jeukendrup AE, Randell R. Fat burners: nutrition supplements that increase fat metabolism. Obes Rev. 2011 Oct;12(10):841-51. 
• Kobayashi K, Nishikawa M, Omay SB, Toyoda H, Deguchi K, Shirakawa S. Forskolin potentiates G-CSF-induced proliferation of a murine myeloblastic leukemia cell line. Leuk Res. 1994 Feb;18(2):111-7.
• Lin H, Wang SW, Wang RY, Wang PS. Stimulatory effect of lactate on testosterone production by rat Leydig cells. J Cell Biochem. 2001 Jun 26-Jul 25;83(1):147-54.
• Pescosolido N, Librando A. Oral administration of an association of forskolin, rutin and vitamins B1 and B2 potentiates the hypotonising effects of pharmacological treatments in POAG patients. Clin Ter. 2010;161(3):e81-5. 
• Roure R, Oddos T, Rossi A, Vial F, Bertin C. Evaluation of the efficacy of a topical cosmetic slimming product combining tetrahydroxypropyl ethylenediamine, caffeine, carnitine, forskolin and retinol, In vitro, ex vivo and in vivo studies. Int J Cosmet Sci. 2011 Dec;33(6):519-26.
• Vetrugno M, Uva MG, Russo V, Iester M, Ciancaglini M, Brusini P, Centofanti M, Rossetti LM. Oral administration of forskolin and rutin contributes to intraocular pressure control in primary open angle glaucoma patients under maximum tolerated medical therapy. J Ocul Pharmacol Ther. 2012 Oct;28(5):536-41.
• Virgona N, Taki Y, Yamada S, Umegaki K. Dietary Coleus forskohlii extract generates dose-related hepatotoxicity in mice. J Appl Toxicol. 2012 Jun 22.
• Yokotani K, Chiba T, Sato Y, Taki Y, Yamada S, Shinozuka K, Murata M, Umegaki K. Hepatic cytochrome P450 mediates interaction between warfarin and Coleus forskohlii extract in vivo and in vitro. J Pharm Pharmacol. 2012 Dec;64(12):1793-801.
• Yu PL, Pu HF, Chen SY, Wang SW, Wang PS. Effects of catechin, epicatechin and epigallocatechin gallate on testosterone production in rat leydig cells. J Cell Biochem. 2010 May 15;110(2):333-42.

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.

D-Finitively Relevant News: Vitamin D Supplementation Speeds Up Strength Recovery and Lowers Markers of Muscle Damage in Vitamin D-Sufficient Young Subjects

If we were all training at "Muscle Beach", we would probably not need any vitamin D3 caps to get our 25(OH)D levels into the recovery friendly 50ng/ml zone. They would already be there!

Ok, I know this looks odd, but it's really total coincidence that all the interesting vitamin D research is published in the last weeks of the year. Unlike the latest vitamin D articles, i.e.

• "Vitamin D Builds Muscle: 70% Reduction in Myostatin, 45% Increase in Myotube Size in 10 Days" |  learn more
• "Leucine, Insulin & Vitamin D*: A Hypertrophy Boosting Triplet That Does Not Make It From the Dish to the Gym?" | read more

today's SuppVersity article does yet leave little room for speculations about it's real-world significance. I mean, how could it, if the paper it discusses is titled "Supplemental vitamin D enhances the recovery in peak isometric force shortly after intense exercise" (Barker. 2013).

You can learn more about vitamin D at the SuppVersity

Vitamin D Builds Muscle

Leucine, Insulin & Vitamin D

Vitamin D = Fat Synthesizer

Overlooked D-Sources

Vitamin D For Athletes!

Vitamin D Helps Store Fat

The title does yet not "say it all". Moreover, what it doesn't tell you is the most important piece of information. The study period was short (35 days) the dose of vitamin D was relatively high (4,000IU) was conducted with "reportedly healthy and modestly active (30 minute of continuous physical activity at least 3 time/week) adult men with low, albeit normal vitamin D levels (25(OH)D ~ 30ng/ml)! The otherwise almost obligatory question about the potential relevance in "normal" human beings does thus become superfluous - and this is true for all the observations the scientists made, i.e.

• ... the linear relationship between baseline 25(OH)D levels and the increase in serum vitamin D in response to the with an up to 150% increase in subjects in the deficiency zone and less than 50% increases in subjects in the >40ng/ml range, ...
• ... the steady serum calcium levels, which make concerns about potentially kidney damaging increases in calcium from vitamin D3 supplementation obsolete, ...

... and, not to forget, the enhanced recovery in peak isometric force the researchers observed in their subjects after these had performed 10 sets of 10 repetitive eccentric-concentric jumps with a load of 75% of their respective body mass on their shoulders and a 20 sec rest period between each set.

For the researchers this is a model of a "muscle damaging event" (P< 0.05; ≈8% at 24-h), which was, as it was to be expected, associated with an increase in the circulating levels of the "liver enzymes"  alanine (ALT) and aspartate (AST) aminotransferase, of which many medical textbook will tell incorrectly tell you that they would indicate a strain on the liver / liver damage, when they are actually only markers of increase amino acid catabolism. The attenuation (P< 0.05) of the immediate and delayed (48-h, 72-h, or 168-h) increase in these enzymes in the vitamin D supplemented group  is thus an indicator of "muscle protective" or at least general protein sparing effects of supplementally increased vitamin D levels.

Figure 1: Strength recovery (%) from immediately post to 24 post workout, left; serum ALT values immediately after, 24h, 72h, and 168h after the exercise test (Barker. 2013).

The fact that the alleged decrease in muscle damage did not correlate with a decrease in muscle soreness does or doesn't negate the purported muscle protective effects of vitamin D. There is, as you should remember from Alex' excellent articles about DOMS, after all no direct link between ALT, AST, muscle damage and delayed onset muscle soreness, aka DOMS (learn more about DOMS). What is clear, though is that there was no consistent trend in the subjective measures of muscle soreness in the study at hand, so that Barker et al. are right, when they state that "[s]upplemental vitamin D was ineffective at abrogating muscle soreness in the SSC leg" (Barker. 2013). If it's an improvement in pain you are looking for, you'd be better off with one of the techniques Alex' discussed in part I of his article series.

Figure 2: It looks boring, but the linear association between the subjects baseline levels and the change in 25(OH)D and the ceiling effect at ~50ng/ml are also important results of the study at hand (Barker. 2013).

Bottom line: I guess you can't have it all, so I would not mourn over the lack of effect on muscle soreness. I mean, come on (!), this is one out of thousand (literally!) vitamin D studies with real-world relevance for you and me. A study that confirms that getting your 25(OH)D levels into the 50ng/ml range can actually have small, but stat. significant beneficial effects on your exercise performance (without negative effects on calcium, btw).

Furthermore, the fact that this increase to the 50ng/ml+ was achieved in all subjects with "only" 4,000IU D3 within only 35 days and was directly associated to their respective baseline level is an intruiging result on its own (see Figure 2). It does after all provide you with a rough guideline of what you have to do if your next 25(OH)D blood test comes back way below the 50ng/ml margin.

Against that background, there is no reason to frown about the fact that we still don't really know what vitamin D actually does to elicit its ameliorative effects on the performance decline in response to potentially muscle damaging stretch-shortening contraction. This was beyond the scope of the study at hand and cannot be investigated in isolated muscle cells... much contrary to the previously reported anabolic effects in the Petri dish, by the way, which may be exciting, but more or less irrelevant, if we can't observe corresponding increases in muscle hypertrophy in the real world.

References:

• Barker, T., Schneider, E. D., Dixon, B. M., Henriksen, V. T., & Weaver, L. K. (2013). Supplemental vitamin D enhances the recovery in peak isometric force shortly after intense exercise. Nutrition & Metabolism, 10(1), 69.

To Spit or to Swallow - That is the Question! Carbohydrate Mouthrinse May Be Better Than Water, Yet Still Not an Option for Performance Oriented Athletes

Image 1: "You need carbs to fuel your workouts!" You know the whole litany... what may be news to you is that scientists are speculating that "intra workout carbs" do not necessarily have to be ingested to do their ergogenic magic.

Those of you, who already "friended" me on Facebook and are following what is going on on the SuppVersity Facebook page (just want to remind you that Facebook has now an option that allows you to be informed, whenever something new is posted), will probably remember the discussion revolving around "carbohydrate mouthrinsing" and whether or not it may be even more beneficial to spit and not to drink your Gatorade... now, all the health benefits of low-carbohydrate (when I am talking "low" I am not talking of Atkins type <80g) diets aside, it does seem pretty counter-intuitive that just swishing one of those carbohydrate-laden electrolyte drinks in between your teeth for a few seconds, to then spit it out again could actually have any merit. Yet, science, or I should say a handful of studies, do suggest otherwise.

As part of their recently published study into the effects of carbohydrate mouthrinsing on exercise capacity in the pre- and postprandial state (Fares. 2011), Elie-J. M. Fares and Bengt Kayser have compiled a list of the 8 hitherto published peer-reviewed papers on that subject. And if you just went by the column "increased perfomance", "yes or no", it appears like it was an established fact that carbohydrate mouthrinsing was highly ergogenic. After all, six out of the eight studies are marked with the tag "increased performance".

Figure 1: Performance increases and standard deviations of the respective measures from studies on the advantage of carbohydrate vs. artificially sweetened or plain water mouthrinse (data calculated based on summary in table 2 of (Fares. 2011)

If we do yet have a look at the quantity of those performance increases and the individual standard deviations (I compiled the respective data for you in figure 1), things begin to look less conclusive. I mean, there is obviously a standard deviation for both arms of each study and there also is a mean improvement (or decrease in performance), but if the "performance increment" is smaller than the standard deviation, for all but one study, this does make me feel uncomfortable with the statement that I would see "scientific evidence", let alone "conclusive scientific evidence" in support of carbohydrate mouth-rinses.

Mouthrinse vs. placebo = minimal (if any advantage), but what about vs. ingestion?

Regardless of what you think about the real world significance of an average performance increase of 1% (calculated based on the data from figure 1), for the small fraction of athletes for whom these minimal performance increases would actually count, i.e. high intensity endurance athletes, like time-trial Tour de France cyclists, the "control", or I should say the "benchmark" should not be plain or sweetened water, but rather one of these crab-, ah... pardon me, carb-loaden sugary electrolyte drinks these athletes are habitually consuming. I was thusly happy to see that Catherine Moss, a student of Sports and Exercise Sciences at the Massey University in Auckland, New Zealand has recently conducted an experiment for her thesis that has much more practical relevance for the high achieving athletes (Moss. 2011).

Table 1: Composition of the placebo and CHO supplement in the Moss study (adopted from Moss. 2011)

In a randomized, counter-balanced, double-blind study, Moss had eight recreationally trained cyclists perform a time trial (with a predetermined amount of work) in the course of which the cyclists ingested or rinsed (swirling 0.33ml/kg body weight of the solution for 8s) with either a placebo solution or a carbohydrate drink, whenever another 12.5% of the total work was done. In that it is worth mentioning that the composition of the CHO solutions differed for the one that was meant to be ingested and the one that was intended to be swished. With the former containing 7.5% and the latter 15% carbs, Moss mimicked solutions that had been used "successfully" previous studies. I do yet no idea, why the placebo did not contain electrolytes, as this could obviously have made a difference at least in the ingestion trials... I guess this is what distinguishes a thesis like this from a study that is worth being published in a peer-reviewed journal ;-)

Figure 2: Mean power output (in Watts) at different time points during time trial (data adapted from Moss. 2011).

As the performance data in figure 2 goes to show, only the ingestion of the carbohydrate led to significant improvements in mean power output, specifically at the later stages of the time trial. This "breakdown" may be explained by the "glycogen reduction exercise protocol" all participants had conducted the day before the time trial. So that after a "low carbohydrate" dinner, the participants were supposed to be glycogen depleted when they performed the time-trial on the subsequent morning.

Figure 3: Total time (in s) during time trial (data adapted from Moss. 2011).

In a way this is an unfair advantage, for the carb ingestion, which accordingly elicited way better time trial times. It does yet not lessen the significance of data on carbohydrate vs. water mouth rinse, which shows pretty conclusively that in a glycogen depleted state both forms of mouthrinsing (plain water or a 15% carbohydrate solution) are equally ineffective, when it comes to actual performance increases.

Figure 4: Pleasure / displeasure feeling during time trial (data adapted from Moss. 2011).

If you do however look at the pleasure/displeasure feeling scale data in figure 4, I would speculate that in a non-glycogen depleted state the carbohydrate-rinsers would have performed significantly better... I mean, without gas in the tank a car won't work even if it "wanted". In view of the fact that the carbohydrate ingestion group did yet pedal at a higher intensity, this would warrant further investigation.

Figure 5: Respiratory exchange ratio (higher values = higher carbohydrate oxidation) during time trial (data adapted from Moss. 2011).

That being said, there was what I consider an interesting effect of carbohydrate rinsing on the respiratory exchange ratio (remember higher values = higher carb oxidation), which would suggest that the theory Fares and Kayser propose (Fares. 2011), according to which the activation of sweetness taste receptors cells (T1R2 and T1R3) in the mouth would explain the previously cited performance "increases" in other studies, may have its merits. What else than the sensation of incoming carbs could explain that the cyclists burned more carbs in the carb mouthrinse compared to the placebo mouthrinse trial (cf. figure 5) - and that in the absence of significant differences in blood glucose or insulin levels?

Spit it or suck it? What's right for you?

While we do not know whether it would make sense to mouthrinse in a glycogen repleted state (yeah, I know +1% ;-), for any athlete interested in maximal performance, simply ingesting his carb + electrolyte drink would certainly be the best option. The (intermittendly) fasting dieter, who wants to maximize his fatty acid oxidation in the course of say his "morning cardio", on the other hand, would be best off with a non-carby electrolyte drink that helps him avoid dehydration and does not compromise (even if the effect is minimal) fatty acid oxidation... what? You want to know who would  benefit from spitting his carbs out? Well, at least based on the current data, mostly the cleaning contractors of your local gym - after all, they would have to work overtime (and be paid overtime) to clean up the mess ;-)

3.2g of Beta Alanine Reduce Rate of Perceived Exertion, Increase Time to Exhaustion and Ventilatory Threshold. Vegetarians, Older People and Diabetics May Benefit Most.

Image 1: If you are into running, ladies, beta alanine is for you ;-)

Those of you who make sure that they are getting their highly educative daily dose of the SuppVersity *rofl* will be aware that today's blogpost is, once again, dealing with beta alanine. Contrary to yesterday's post, which dealt with its pharmacokinetics, we are today going to have another look at what kind of real world performance outcomes the average (female!) physical culturist can expect from taking at least 3.2g of the beta amino acid per day - a dosage that has been shown in previous studies to increase intra-muscular carnosine levels by 27–39% in fast- and slow-twitch muscle fibers, respectively (Baguet. 2009). And though I do not want to spoil things, I can already tell you that the results make it quite clear why beta alanine is not the next creatine.

Somehow ergogenic, yet not really antioxidant

For the study that was conducted at the Applied Physiology Laboratory at the University of North Carolina, study that was conducted by A.E. Smith recruited 24 "recreationally active" women, of which the authors state that they "engag[ed] in 3–7 days per week of aerobic, resistance or recreational activities, but were not highly trained competitive athletes". With a mean age of 21.8 years, a height of 165cm and a body weight of 61.5kg the subjects are thusly representative of the average young woman who goes to the gym to either get or keep in shape. I am specifically emphasizing this, because - at least in the early days - beta alanine was heavily marketed as "the creatine for women" who fear the water retention people still claim was an inevitable side effect of creatine supplementation.

Image 2: If you retain water, this is not due to creatine monohydrate. Either you are taking to much (creatine loading is a thing of the past) or you have bought a product with shitloads of carbs in it - in that case, chances are its not only water you are gaining ;-)

Does creatine supplementation inevitably lead to water retention and weight gain? Just because this myth is still perpetuated, especially among female figure competitors, I thought it may be worth addressing this again: Pure creatine monohydrate without the sugar and the other bullshit you will find in many creatine supplements does not necessarily lead to increases in either total body or water weight. A study by Rawson et al. showed only recently that the consumption of 0.03g/kg creatine for six weeks did not result in statistically significant changes in body weight or water in men or women, despite significantly increased plasma creatine concentration and enhanced resistance to fatigue during repeated bouts of high-intensity contractions (Rawson. 2011).

The women were advised to simply stick to their usual routine and to refrain from taking any supplements and medications except from their 2x800mg beta alanine tablets. The latter were to be taken 3x a day... so according to Cocker, they should have consumed 2x0.8g x3/day = 4.8g/day and not, as the scientists state "3.2 g daily". Now, according to Smith et al. this was the "required dosage" all participants met. I can however not say, whether this means that the third dose was optional... and this is not the only oddity in this study, where it is well worth to look beyond the assessments and conclusions of the authors.

At the beginning and the end of the 28-day supplementation period, the women had to perform a graded oxygen consumption test (VO2max) to evaluate VO2max, time to exhaustion, ventilatory threshold and establish peak velocity (PV), as well as a "non-damaging treadmill run (oxidative stress run) for 40 min at 70% PV [peak velocity]". Before, immediately after and in the 2-6h post running window total antioxidant capacity (TAC), superoxide dismutase (SOD), 8-isoprostane (8ISO) and reduced glutathione (GSH) were measured. In addition to that, heart rate and ratings of perceived exertion were recorded during the 40 min run. The two main metrics of the study were thusly the potential anti-oxidant effects (TAC, SOD, 8ISO, GSH) and the anticipated immediate ergogenic effects (VO2Max, time to exhaustion, heart rate and perceived exertion) of beta alanine supplementation.

Figure 1: Effect of 28 days of beta alanine supplementation on maximal oxygen consumption (VO2max), time to exhaustion during a graded exercise test (VO2TTE) and ventilatory threshold (VT) and qualitative practical significance (data and caption adapted from Smith. 2011)

If you now have a look at the my graphical rehash of the scientists own evaluation of the effect beta alanine supplementation had on VO2Max, the time to exhaustion (VO2TTE) and the ventilatory threshold (VT), you will have to concede that mean improvements of 0.28%, 6.6% and 3.7%, respectively, as well as the large discrepancies among the subjects (from beneficial over negligible to harmful) do not actually speak for beta alanine.

Figure 2: Effect of beta alanine supplementation on oxidative stress markers measured as total
antioxidant capacity (TAC) and glutathione (GSH) and the qualitative practical significance
for women (data and caption adapted from Smith. 2011)

Things get even more confusing when we take a look at the antioxidant effects of beta alanine. Not only were the levels of superoxide dismutase (SOD) and 8-isoprostane (8ISO) not different between groups, and the effect of beta alanine on the total antioxidant capacity (TOC) of the subjects negligible, the scientists' summary of the effects does even suggest that, after an initial amelioration of the negative effect of treadmill running on GSH, there was some sort of a "likely harmful" rebound 6h after the 40 min exercise bout. Before you do now flush your beta alanine stores down the toilette, I suggest you first take a look at the actual (absolute) effects beta alanine supplementation had on the exercise induced changes in GSH levels:

Figure 3: Absolute GSH levels (in µM) immediately before (pre), post, 2h and 4h after treadmill running in the placebo and beta alanine supplemented women before (pre) and after (post) the 28-day supplementation period (compiled based on data from Smith. 2011)

As you can see in figure 3, there was an (unexplained) increase in GSH in the course of the 28-day supplementation period in both groups. With 2%, the latter was statistically non-significantly greater in the beta alanine group, and the "likely harmful" effect of beta alanine supplementation 6h after the end of the treadmill-run is simply the result of a smaller increase in GSH, when you compare the pre- to post-supplementation levels at the 6h mark - and I guess, you would agree that a +27% increase in GSH is not exactly something that deserves to be called "likely harmful", wouldn't you?

All-clear: Beta alanine is not ergolytic ;-)

Now that we have gotten that straight, let's get to the last (and most) significant benefit the women in the beta alanine group had from taking the supplement: a statistically significant reduction in the rate of perceived exertion during treadmill running (cf. figure 4).

Figure 4: Rates of perceived exertion during 40 min treadmill running before (pre) and after (post) 28 days of supplementation with beta alanine or placebo; small graph: relative difference post supplementation in women receiving BA vs. placebo (data calculated based on Smith. 2011)

It goes without saying that being 18% less fatigued is something that could well be worth spending the roughly 7$ for a 28-day supply on (calculation based on a dose of 3.2g per day taken over 28 days and assuming you buy your beta alanine in bulk at one of the major suppliers). This, by the way, could be particularly true if you belong to one of the following groups, who have been found to have low intra-muscular carnosine levels, to begin with:

Image 3: Older people are only one of the three groups who are "at risk" of low carnosine levels and are thusly most likely to benefit from beta alanine supplementation.

1. vegetarians - a 2011 study by Evaraert et al. found that "Vegetarians have a lower carnosine content of 26% in gastrocnemius compared to omnivores" (Everaert. 2011); and according to another recent study, the soleus carnosine content of vegetarians was "non-significantly" reduced by -9% after 5 weeks of sprint training, while the same protocol elicited increases of +11% in omnivores (Baguet. 2011)
2. older people - Evaraert et al. found a linear decline (ca. -10% in 20 years) in carnosine levels with age (correlation r=-0.26; Everaert. 2011); and Stout et al. report a highly significant +29% increase in physical working capacity at the fatigue threshold in twenty-six men (n = 9) and women (n = 17) (age ± SD = 72.8 ± 11.1 yrs) who  had been supplementing with 800 mg three times per day for 90 days (Stout. 2008)
3. type-2 diabetics - according to Gualano et al. type-2 diabetics have "significantly lower carnosine content (−45%) in gastrocnemius muscle", a relative deficiency of which the scientists argue that it "may be partially associated with defective mechanisms against oxidative, glycative and carbonyl stress in muscle." (Gualano. 2011)

After all, it does yet not really matter whether you are a type-2 diabetic, a vegetarian or simply getting older, compared to many (if not most) of the other overpriced ergogenics that are advertised all over the web, beta alanine is certainly not only one of the cheapest, but also one of the most promising candidates for the 3rd place on your list of staples, where (whey) protein and creatine should nevertheless still occupy position 1 and 2, respectively. And the fact that it did not prove to be a potent antioxidant in this study need not really be a disadvantage, after all, we still do not know whether the exercise-induced oxidative "damage" is not what actually triggers the highly desirable adaptive responses (cf. previous posts on "hormesis"), we are all looking for, when we are hitting the gym.

Chronic High Dose BCAA Supplementation Reduces Endurance Performance by 43% Plus: How Ammonia, Glutamine, Arginine & Low Carb Could be Involved

Tired, exhausted, had to cut your workout short today? Is it the flu, or just too much BCAAs?

When some is good and more is better, even more is not necessarily going to be 'betterer' - and that's not simply due to the fact that there is no comparative to an adjective that's already in the comparative. Therefore it is actually not surprising that a team of researchers from the Department of Food and Experimental Nutrition at the Faculty of Pharmaceutical Sciences, the Department of Nutrition at the School of Public Health and the Department of Physiology and Biophysics at the Institute of Biomedical Sciences of the University of Sã o Paulo in Brazil has just published the results of a study (Falavigna. 2012) which demonstrates that there is an upper limit to the benefits of BCAA supplementation. What I guess will be surprising at least for some not so regular SuppVersity visitors, is that there is more than just a saturation effect: Too much BCAAs can actually have ergolytic (= anti-ergogenic) effects - at least under certain circumstances.

Another chapter in the book of good things that turn against you, when taken in excess

In their latest paper that has just been published in nutrients, Gina Falavigna and her colleagues analyzed effects of chronic BCAA supplementation on exercise performance in male Wistar rats. Based on previous animal and human data and the still widely supported, though actually experimentally non-validated (cf. Meeusen. 2007) theory that BCAAs would work their non-hypertrophy specific, endurance enhancing magic via the blockade of exercise induced 5-HT (serotonin) accumulation in the brain, the researchers speculated that ...

"[...] chronic BCAA supplementation (through the diet, using different BCAA  concentrations) would increase performance in rats subjected to a swimming exhaustion  test." (Falavigna. 2012)

To verify this hypothesis, Flavigna et al. randomized their rats to three different groups receiving either the standard AIN-93M diet for the maintenance of adult rodents (control group) or the same diet with additional additional 3.57% (group S1) and 4.76% (group S2) BCAAs at a ~2:1:1 ratio of lecine : valine : isoleucine (the BCAAs were manufactured by the Brazilian branch of Ajinomoto). The rodents in the S1 and S2 groups did thus receive 50% and 100% more branched-chain amino acids than the rodents in the control group which had to contend themselves with the BCAAs in the casein fraction of their diets (see figure 1, right). In order to assure that the diets would be isocaloric, an amount of starch equivalent to the amoung of BCCAs that had been added to the chow was removed from the supplemented diets.

Overall, the study lasted for six weeks. During this time the rodents were subjected to a 1h/day weight bearing swimming protocol five times a week. In the first two weeks, the rats were ...

"[...] adapted to the water medium and exercised with increasing overloads attached to the tail until an overload corresponding to 5% of total body weight was reached. This final overload was used until the end of the training protocol [...] The overloads were corrected weekly according to the variations in animal weight.  The efficiency of the training protocol was assessed on the basis of maximum activity of the enzyme citrate synthase in the soleus muscle, with a group of sedentary animals being used as the control for this parameter." (Falavigna. 2012)

Neither the overall amount of food nor the body weight gain of the rodents in the control, and the two exercise groups showed any statistically significant difference. The latter cannot be said about the exercise performance, as well as the accumulation of ammonia, though (see figure 1):

Figure 1: Exercise duration and plasma ammonia levels during / after swmming test (left) and macronutrient composition of the experimental diets (right; based on Falavigna.. 2012)

While the rodents in the +50% BCAA group (S1) do show the expected increase in endurance (+37%) their peers in the high dose (+100%) BCAA group (S2) experienced an even more pronounced drop in endurance performance (-43% vs. control), which went hand in hand with a profound increase in blood ammonia (+34%).

"Ammonia is a ubiquitous metabolic product producing multiple effects on physiological and biochemical systems. Its concentration in several body compartments is elevated during exercise, predominantly by the increased activity of the purine nucleotide cycle in skeletal muscle. Depending on the intensity and duration of exercise, muscle ammonia may be elevated to the extent that it leaks (diffuses) from muscle to blood, and thereby can be carried to other organs. The direction of movement of ammonia or the ammonium ion is dependent on concentration and pH gradients between tissues. As such, ammonia can also cross the blood-brain barrier, although the rate of diffusion of ammonia from blood to brain during exercise is unknown. It seems reasonable to assume that exhaustive exercise may induce a state of acute ammonia toxicity which, although transient and reversible relative to disease states, may be severe enough in critical regions of the central nervous system (CNS) to affect continuing coordinated activity. Regional differences in brain ammonia content, detoxification capacity, and specific sensitivity may account for the variability of precipitating factors and latency of response in CNS-mediated dysfunction arising from an exercise" stimulus, e.g., motor incoordination, ataxia and stupor. There have been numerous suggestions that elevated ammonia is associated with, or perhaps is responsible for, exercise fatigue, although evidence for this relies extensively on temporal relationships." (Falvigna. 2012; my emphasis)

Mark the last words of the previously cited paragraph: "[E]vidence for [the role of ammonia] in exercise fatigue relies extensively on temporal relationships". It is thus - as for now - a solely corollary, not yet a causative association, of which I do however feel that it would be very likely to turn into a causal one if someone actually measured the influx of ammonia into the brain during a workout.

Wait, ammonia? But ain't it more likely that the BCAAs block the uptake of tryptophan?

What's for sure is that another hypothesis, which relates to the blockade of tryptophan uptake can be ruled out as an underlying reason of the differences. After all the scientists who argue that ...

"[t]he increased synthesis of serotonin during exercise may be related to the development of central fatigue, because this neurotransmitter has several physiological functions, since it operates by  mood, lethargy, individual behavior, regulation of sleep, body temperature and blood  pressure, appetite suppression and changes in perceived exertion." (Falavigna. 2012)

...actually measured the 5-HT levels and observed no differences between the dietary groups. Overall, the study results to thus clearly indicate that both, medium nor high dose "chronic BCAA supplementation was not effective in improving the main parameters indicative of central fatigue" (Falavigna. 2012) - well, at least as long as we still stick to the hypothesis that the latter is induced by the accumulation of 5-HT in the brain.

Forget about tryptophan and serotonin, focus on ammonia

The fact that neither the high, nor medium dose of BCAAs did exert any effects on the serotonin levels in the brain does yet not explain why the medium dose supplementation regimen produced ergogenic, while the high dose regimen induced ergolytic effects.

The occurrence of direct toxic effects due to (too) high amounts of branched-chain amino acids can be ruled out based on previous studies in which the administration of more than 10g/kg body weight of BCAAs (the human equivalent would be 130g+ per day), as well as dosages of 2.5g/kg body weight chronically did not entail any toxic side effects (Shimomura.  2004). The same is true for other confounding variables, such as the citrate synthase activity, a measure of the general efficiency of the training protocol, bood glucose, insulin,free fatty acids, and lactate levels, as well as liver and muscle glycogen content, which were virtually identical in both groups. This leaves us with the increase in plasma ammonia as our 'last resort' to explain the -58% shorter swimming time in the high (S2) vs. medium (S1) dose BCAA group (-43% lower vs. non-supplemented control).

Figure 2: The reduced performance of the high BCAA group could well be related to peripheral and/or central ammonia build-up as a results of increased BCAA oxidation, camparably low glutamine intakes and the rate-limited enzymantic conversion and recycling of gluatmine (illustration originally from Earrante. 2003). Studies by Snow (2000) and Carvalho-Peixoto (2007) suggest: Both carbohydrate & glutamine supplements could help.

Based on what we know about the mammalian body, the increased build-up of ammonia in the high BCAA group could be a result of the unfortunate combination of temporary energy shortage and learned wastefulness' in a situation, where the otherwise sparse BCAAs are available in abundance. Furthermore, with a glutamine content of only 9-13% in the casein fraction of their diets (Swails. 1992), the rodents in the high BCAA group did ingest more than 2.6-3.8 times more BCAAs than glutamine; a fact which may have contributed to a temporary glutamine deficiency as a result of its increased use in the detoxification of the ammonia that's generated when the BCAAs are oxidized. The resulting peripheral and possibly central ammonia build-up (see figure 2) could then have begun to intoxicate liver and brains of the rodents and thus hampered gluconeogensis (normal levels stimulate, high levels of ammonia hamper gluconeogensis; cf. Fritz. 1988) and induced central fatigue (Wagenmakers. 1990; Nybo. 2004) -- and that not despite, but rather due to the chronic "high dose" BCAA supplementation (HED ~50g/day).

So do I have to drop my BCAAs now or what? Whether these results are relevant for you will probably depend on a whole host of parameters, which include

• the type, intensity and duration of exercise you do, 
• the ratio of BCAAs to glutamine in your diet,
• the amount of arginine, which acts as a substrate for the urea cycle and is therefore necessary to for the excretion of ammonia by the kindeys (Schaefer. 2002),
• the amount of carbohydrates in your diet (with more = less amino acid oxidation = lower ammonia and very low carb = you are in trouble; e.g. Czarnowski. 1995; Snow. 2000; Carvalho-Peixoto. 2007), 

... and those factors I will probably have forgotten to mention now. Unless you don't forget that you can neither lifve from BCCAs and protein alone, but accept the neflglected truth that too much protein is about as bad a too little protein, you can file this post under "show your stupid friends" and get back out, when they complain about feeling sick, bloated and fat "despite" eating a BCAA supplemented high protein, low carb (and often even low fat) diets.

References:

• Carvalho-Peixoto J, Alves RC, Cameron LC. Glutamine and carbohydrate supplements reduce ammonemia increase during endurance field exercise. Appl Physiol Nutr Metab. 2007 Dec;32(6):1186-90.
• Errante LD, Petroff OA. Acute effects of gabapentin and pregabalin on rat forebrain cellular GABA, glutamate, and glutamine concentrations. Seizure. 2003 Jul;12(5):300-6.
• Falavigna G, de Araú jo Junior JA, Rogero MM, de Oliveira Pires IS, rio Graç a Pedrosa R, Martins Junior E, Alves de Castro I, Tirapegui J. Effects of Diets Supplemented with Branched-Chain Amino Acids on the Performance and Fatigue Mechanisms of Rats Submitted to Prolonged Physical Exercise. Nutrients 2012. 4; 1767-1780.
• Fritz S, Bohnensack R. Stimulation of alanine metabolism in rat liver by ammonia. Biomed Biochim Acta. 1988;47(12):923-32.
• Meeusen R, Watson P. Amino acids and the brain: do they play a role in "central fatigue"? Int J Sport Nutr Exerc Metab. 2007 Aug;17 Suppl:S37-46.
• Nybo L, Dalsgaard MK, Steensberg A, Møller K, Secher NH. Cerebral ammonia uptake and accumulation during prolonged exercise in humans. J Physiol. 2005 Feb 15;563(Pt 1):285-90. Epub 2004 Dec 20. 
• Schaefer A, Piquard F, Geny B, Doutreleau S, Lampert E, Mettauer B, Lonsdorfer J. L-arginine reduces exercise-induced increase in plasma lactate and ammonia. Int J Sports Med. 2002 Aug;23(6):403-7.
• Shimomura, Y.; Murakami, T.; Nakai, N.; Nagasaki, M.; Harris, R.A. Exercise promotes BCAA catabolism:  Effects  of BCAA supplementation on skeletal muscle during exercise.  J. Nutr.  2004, 134, 1583S–1587S.
• Snow RJ, Carey MF, Stathis CG, Febbraio MA, Hargreaves M. Effect of carbohydrate ingestion on ammonia metabolism during exercise in humans. J Appl Physiol. 2000 May;88(5):1576-80.
• Swails WS, Bell SJ, Borlase BC, Forse RA, Blackburn GL. Glutamine content of whole proteins: implications for enteral formulas. Nutr Clin Pract. 1992 Apr;7(2):77-80.
• Wagenmakers AJ, Coakley JH, Edwards RH. Metabolism of branched-chain amino acids and ammonia during exercise: clues from McArdle's disease. Int J Sports Med. 1990 May;11 Suppl 2:S101-13.

HMB Exhibits Differential Effects on ATP and Glycogen Content of Fast & Slow Twitch Fibers and Maximizes Tetanic Force Development in Rodent Study

Image 1: This is where HMB could actually make a difference, the two more reps, the one more sprint, which after weeks and months of training can decide over victory or defeat.

Sometimes, or I should say, time and again (!), it amazes me how the same people who are willing to invest hundreds of bucks in a supplement, which (according to the patent holder) "has been shown in scientitfic studies" (which were conducted by the researcher and a buddy of his at a remote lab, only to file the patent) to "increase testosterone by up to 147.34%", keep telling me that they "would never waste their hard earned money on supplements like HMB..." hello? Am I missing something, here? I mean, right; HMB does not produce the steroid-like effects the same sort of shady businessmen who are now promoting a new natural testosterone booster as legal alternative to Anavar on a monthly base once claimed it would have, but in all  honesty, the scientific research on HMB is by far more promising than the mostly non-existent research on 99% of the "legal anabolics" out there.

HMB works, we just don't know exactly how and for whom

As Dr. Connelly pointed out on the last BodyRX Show (highly recommended, especially for Layne's intellectual exchange with Dr. Jeff Volek), it stands out of question that HMB works. There are in fact more than a dozen of studies which show that supplementation with adequate amounts of this leucine metabolite has anti-catabolic effects in various conditions of skeletal muscle atrophy (Nissen. 2003; Smith. 2005). What  is still debatable, though is whether and to which extent athletes, in general, and bodybuilders, in particular can benefit from these effects. In view of the increasing awareness of the importance of leucine, the metabolic precursor of b-hydroxy-b-methylbutyrate (HMB), most athletes in this subgroup probably consume somwhere between 20-30g of leucine from the 300g of protein they are feeding themselves in the form of protein shakes and lean meats alone (with reference to the data that is presented in figure 1 it is noteworthy that the comparison Nissen made is not "fair", because the many of the HMB studies were conducted with "sick" people, while the majority of studies on protein supplements used either healthy people or athletes). With an average conversion rate of ~5% (of dietary leucine), we would have to estimate their daily HMB "production" to roughly 1.0-1.5g, which is interestingly at the lower range of what has been shown to ameliorate muscle wasting in cancer cachexia studies (Eley. 2007; Kovarik. 2010).

Figure 1: Calculated effect sizes of creatine, HMB, chromium, androstendione, DHEA and protein supplements on strength and lean mass gains (adapted from meta-review by Nissen et al.; Nissen. 2003)

And even if we discard the question of whether or not additional HMB is really necessary on a high protein diet and whether or not respective dietary differences could explain the negative results from some, yet by no means all, trials with professional athletes, we must still admit that even in those cases where it does work, we (i.e. scientists) do not really understand how HMB does its anti-proteolytic magic. The results of a recently published study from scientists from the Institute of Biomedical Science at the University of Sao Paulo, could thusly be of particular importance, as this is - at least to my mind - the first study to investigate the effects HMB supplementation had on ATP and glycogen levels, citrate synthase and changes in the contractive properties of individual muscle fibers (Pinheiro. 2011).

Figure 2: Changes (vs. placebo) in ATP and glycogen content, as well as citrate synthesis in red and white portion of rat gastrocnemius muscle after 4 week supplementation with 320mg/kg HMB (data adapted from Pinheiro. 2011)

The data in figure 2 shows, that after 4 weeks of daily supplementation with 320mg/kg HMB (in the study the usual calcium salt, you can buy in bulk on the Internet was used), the ATP and glycogen levels in the gastrocnemius muscle of the rats were profoundly elevated. In that, it is particularly interesting that the leucine metabolite had differential effects on the slow-twitch oxidative red portion of the muscle and the fast-twitch glycolytic white portion: In the slow twitch fibers the increase in ATP is 10x higher than it is in the fast twitch fibers, where the +400% increase in glycogen content should yet provide a similarly extensive buffer of readily (yet not immediately) available energy. Moreover, the increase in citrate synthesis (+67%) in the slow twitch fibers suggests that part of this effect was mediated by an "increased lipid availability due to increased lipolysis", or, put simply, by an increased oxidation of fatty acids to generate more ATP.

Figure 3: Tetanic force production (normalized to muscle weight) in rats receiving 320mg/kg HMB or placebo for 4-weeks; successive tetanic contractions were evoked at 100 Hz each 10 s of interval (data adapted from Pinheiro. 2011)

These increase in both readily available energy stores and the ability to replenish the former via fatty acid oxidation, is - according to Pinheiro et al. - also the underlying reason for the "increase in resistance to fatique" the scientists observed when they subjected the rat muscle to electrical stimulation in order to evaluate the tetanic (=constantly contracting) force production (cf. figure 3). Contrary to the twitch force, which was identical in supplemented and non-supplemented rats, the tetanic force production (normalized for either muscle weight or muscle cross-sectional area) increased by +17% (p<0.05; meaning that the chance that this was mere coincidence is <5%).

Fine!? Now, tell me: Is HMB worth it?

In view of the fact that neither the muscle size (cross-sectional area) nor the lean mass of the rodents in the HMB group differed from their placebo supplemented peers (btw. the animals were not "trained" in the course of the 4-week study), we must conclude that the effects of HMB, similar to those of creatine, are not what you would call "immediately anabolic". In a real world training scenario the metabolic advantage (increased ATP stores, increased glycogen stores and increased oxidative capacity) the rats in the HMB group gained over the 4-week study period, would allow trainees to do those 1-2 reps more which in weeks and months would then translate into this one additional pound of muscle or the 10th of a second that can make the difference between victory or defeat - whether those 1-2 reps are worth the roughly 64$ it would cost to copy the supplementation regimen used in the study (320mg/kg in rats would equate to 53mg/kg per day for humans), does yet depend on who you are, what you want to achieve and how much money you have to spend... and if you do not have your regular diet and training in check, don't even think of HMB (let alone one of those "test boosters" ;-)