SuppVersity Science Round Up Seconds: Wheat Gluten Hydrolysates Fail, Exposure to Air Pollutants During Workout Reduces Brain Benefits, Homocysteine, B-Vitamins, Cognitive Impairment and Mortality

Before the profound weight loss (A) you don't see any of the glucose sucking and fad burning brown fat depots (black spots in B) on the neck of the in (B) 'foermerly obese', now only 'overweight' subject (also take a look at how the visceral fat in the abdominal region in (A) is actually pushing the organs upwards; img Vijgen. 2013)

Those of you who have listened to yesterday's show will have noticed that despite its flow the number of things you can discuss in a 1h podcast is simply very limited, to say the least. This is also why these Friday posts are probably never going to be simple summaries of the SuppVersity Science Round Up of the day before. The same is true for today and still I decided not to use the allegedly lame logo I did for the first two installments, but provide you with some 'real science' evidence of the absence of brown adipose tissue on the obese and it's magical reappearance after shedding 100lbs+ subsequent to a gastric bypass operation, instead (see image on the right).

Assuming that you have no idea what this "evidence" is for, I would suspect that you missed the live show yesterday and also did not find the time to download and listen to the podcast, yet -- right? Well, you should either download and listen to the show now and digest the Seconds later, or you read the following paragraphs first and download the podcast later.

What is not an option, however, is to miss one or another - I mean you can hardly want to eat the seconds if you have not had the main dish yet... and after listening to the podcast, I cannot imagine you don't want at least some seconds. Apropos seconds, here are today's seconds...

• Wheat gluten hydrolysate is not the new goto protein supplement - certainly not for female distance runners and probably not for anyone else, either! These are the kinds of studies that really annoy me. Studies that start out with blatant statements like "WGH [Wheat gluten hydrolysate] has been reported to suppress post-exercise rises in serum creatine kinase in male distance runners" (Hirao. 2013).
  
  

  

  Figure 1: CK, AST, ALT response in the "success trial" with men. In women even the miniscule beneficial effect on CK was not there. No reason to even think about buying a gluten hydrolysate as you new go-to protein supplement with only 5.6g of leucine/100g (whey has 50% more) and almost no GSH replenishing cysteine in it (0.9g vs. 3g+ in whey, which is more than +200% more).

  Sentences like that make the null-results of the study they precede look like the exception to the rule and are still nothing but a concession to a bias (let's hope not due to the grant from Nisshin Pharma Inc. which was the manufacturer of the wheat gluten hydrolysate used in this study). A bias, due to which an isolated observation as the slightly blunted increase in CK is blown up as if a slightly lower CK level was what could turn a sedentary pencil pusher into the next Hussein Bolt (Aoki. 2013).
  
  So, even if you are not afraid of the evil in gluten (which I believe not everyone has to), I strongly caution against making the switch from a high EAA protein with ton's of GSH boosting cysteine in it like whey to a mediocre grain protein, which is a potential allergen and contains tons of glutamine your body will readily turn into glucose, once it passes through the portal veign into the liver (I bet a large part won't even make it into systemic circulation).
  
  And as far as the purported "gender difference" goes the study at hand tries to blame the null result on (Hiriao. 2013), I suspect that it is rather the indisputable difference between the long-distance running at a continuous pace the women in the study at hand did, versus the totally different strains the guys in the previous study were exposed to during a soccer training + mini-match, which made the difference.
• Working out next to a street takes away some of the beneficial cognitive effects due to ultrafine particulate matter (UFPM) exposure. "Working out in the fresh air will promote weight loss more than working out inside." You heard me state that in one of the previous installments of the SuppVersity Science Round Up on Super Human Radio. Now this is still correct and based on sientific evidence, but at least as far as the cognitive benefits are concerned, working out outside does also have its downsides - at least for those of you who live in the inner city area.
  
  

  

  You better watch what you breath while you run.

  During a 12-week program the researchers from the Universiteit Brussel, the Hasselt University and the Royal Military Academy measured the improvements in physical performance, changes in serum markers and corresponding ultrafine particulate matter (UFPM) concentrations in the enviromnent in which their 15 previously untrained subjects conducted their aerobic training program thrice a week (Bos. 2013). What Bos et al. found was that the UFPM levels were signfificantly higher in the urban compared to the rural environment and that the higher UFPM exposures correlated with increases in leukocyte counts (p = 0.02), neutrophil counts (p = 0.04), and eNO levels (p = 0.002) that were exclusively observed in the group that trained in the urban environment.
  
  With the latter being markers of inflammation which exert their effects systemically, i.e. not just in the lung or musculature of which you may be thinking now, but also in the brain, it is no wonder that
  

  "reaction times on the Stroop task improved in the rural group (p = 0.001), but not in the urban group" (Bos. 2013). 

  What's comforting, though, is that the physical fitness did increase to a similar extend in both arms of the study.
• Homocysteine levels, mortality, cognitive impairment and which nutrients can offer some protection. I am not sure about what your impression is, but for whatever reason homocystein seems to be 'out of vogue' -- probably no room for it on the research agenda with all the hype surrounding vitamin D. It used to be all the rage in CVD risk research and today's news item is actually ain't about cardiovascular health, either.
  
  What the researchers from China and Taiwan actually were interested in was the correlation of high and low homocysteine levels with cognitive impairment and the corresponding nutrient intakes. In that Xiu et al. paid particular attention to the "B-vitamins" and found the following correlations between the mortality, cognitive status, homocystein levels and nutrient intake of their 1412 study participants (Xiu. 2013):
  

  • 

    Figure 2: Unadjusted mortality in the four quartiles of homocysteine levels (top); mortality according to homocysteine levels in subjects with different degrees of cognitive impairment (based on Xiu. 2013)

    if you go by the unadjusted data in figure 2, it's plain obvious that the all-cause mortality increases linearly from one quartile to the other 
  • this relation between plasma homocysteine levels and all mortality remained statistically significant after adjustments for age, sex, smoking status, BMI, physical function and general health were made
  • of the general foods, the scientists assessed, only regular fish intake had a statistically significant effect on homocysteine levels, with higher intakes being associated with lower homocysteine levels
  • of the b-vitamins choline was the only one with a significant association with plasma homocysteine levels (suggested read "Old School Supplement Choline Could Save Your Live and Liver!") 
  • neither betaine, nor vitamin B1, B2, B3 or B6 intakes did show statistically significant correlations with plasma homocysteine (not even "borderline significant; p > 0.15 for all, most way hither)
  • of the plasma markers, folate showed a highly significant correlation with homocysteine (14.4 nmol/L in the lowest HCY and 8.70 nnmol/L in the highest HCY group)
  • PLP, the active form of vitamin B6, came in close second with 70.3 nmol/l in the lowest HCY quantile and only 44.4 nmol / l in the highest quantile.
  Now, if you consider the fact that higher intakes of B-vitamins are probably not doing much to lower homocysteine levels int he elderly (at least not dose-dependently, when they are already getting enough) oddity #1, another look at the data in figure 2 will reveal oddity #2: The surprisingly high mortality in the lowest homocysteine quartiles in the patients with severe cognitive decline - how come? I mean, with low homocysteine they should not be at risk of having severe cognitive decline, anyway - right?
  
  Actually if you follow this rationale you can almost answer the question yourself. If you have low homocysteine and severe cognitive decline, the severe cognitive decline can hardly be from high homocysteine levels, so it must have another obviously pathological reason, or as the scientists have it
  

  "The joint effects of the 2 variables [homocysteine and cognitive decline] were most pronounced with severe cognitive impairment where mortality HRs ranged from 5- to 18-fold across a wide range of homocysteine concentrations. The findings with hypohomocysteinemia provide some insight into what might be an optimal range for this analyte in peripheral blood and tissues. The low concentrations may be seen with severe illness and malnutrition, and our study population comprises the health-vulnerable aged. For these reasons, we adjusted these associations for BMI (using the World Health Organization chronic energy deficiency category of, 18.5 kg/m 2 ), and we excluded those who died in the first year of follow-up. The findings were unchanged. Because mortality among the very old may have skewed the joint effects, these are presented for those ≤75 years and over, but again with similar findings." (

  A sarcastic person would now probably say: "We all have to go some time!" and just wave his hands at these results. True! And I am the last to advice you to become over-anxious. Yet in the mean time it would appear prudent to make sure to get your homocysteine levels checked from time to time, not to forget that choline is a b-vitamin as well and not to fall for the idea that you cannot overdose on B-vitamins - I don't have to remind you of the negative effects, specifically folic acid supplementation can have on all sorts of cancer (e.g. breast cancer, where a high folic acid intake from foods and supplements is associated with a +30% risk of cancerous growth; cf. Kim. 2006).

In case you are looking for the post on "ammonia accumulation brain-fog, toxicity, liver 'pathologies' and workout performance", yeah it was on the list, but I decided it would be a shame to tackle that within a short two paragraph seconds items. Don't worry I am not going to forget about it, after all its in my humble opinion one of the main reasons the diets and workout regimen of the many ambitious physical culturists fail. If you are still looking for more and have not listened to the podcast, yet, this would be the right moment to download the file from the Super Human Radio Network server (click here to download), otherwise the latest short news on the SuppVersity Facebook Wall may offer some diversion ;-)

References:

• Aoki K, Kohmura Y, Suzuki Y, Koikawa N, Yoshimura M, Aoba Y, Fukushi N, Sakuraba K, Nagaoka I, Sawaki K. Post-training consumption of wheat gluten hydrolysate suppresses the delayed onset of muscle injury in soccer players. Exp Ther Med. 2013 Jun;3(6):969-972. Epub 2013 Apr 3.
• Bos I, De Boever P, Vanparijs J, Pattyn N, Panis LI, Meeusen R. Subclinical Effects of Aerobic Training in Urban Environment. Med Sci Sports Exerc. 2013 Oct 15.
• Cankurtaran M, Yesil Y, Kuyumcu ME, Oztürk ZA, Yavuz BB, Halil M, Ulger Z, Cankurtaran ES, Arıoğul S. Altered Levels of Homocysteine and Serum Natural Antioxidants Links Oxidative Damage to Alzheimer's Disease. J Alzheimers Dis. 2013 Oct 29.
• Guest PC, Urday S, Ma D, Stelzhammer V, Harris LW, Amess B, Pietsch S, Oheim C, Ozanne SE, Bahn S. Proteomic analysis of the maternal protein restriction rat model for schizophrenia: Identification of translational changes in hormonal signalling pathways and glutamate neurotransmission. Proteomics. 2013 Oct 16.
• Hirao T, Koikawa N, Aoki K, Sakuraba K, Shimmura Y, Suzuki Y, Sawaki K. Female distance runners show a different response to post-workout consumption of wheat gluten hydrolysate compared to their male counterparts. Exp Ther Med. 2013 Apr;3(4):641-644.
• Kim YI. Does a high folate intake increase the risk of breast cancer? Nutr Rev. 2006 Oct;64(10 Pt 1):468-75.
• Vijgen GH, Bouvy ND, Teule GJ, Brans B, Hoeks J, Schrauwen P, van Marken Lichtenbelt WD. Increase in brown adipose tissue activity after weight loss in morbidly obese subjects. J Clin Endocrinol Metab. 2013 Jul;97(7):E1229-33. Epub 2013 Apr 24.
• Xiu LL, Lee MS, Wahlqvist ML, Chia-Yu Chen R, Huang YC, Chen KJ, Li D. Low and high homocysteine are associated with mortality independent of B group vitamins but interactive with cognitive status in a free-living elderly cohort. Nutr Res. 2013. Ahead of print.

Aspartame's Anti-Insulinogenic Effects During a Workout; Optimal Protein Intake on a Diet is Relative. Plus: Folate Fortification, Spirulia, Succinate, Sucrose, Pork Brain & the Low Cholesterol-Suicide Connection Reviewed!

Unbelievable: The results of the latest study from the University of Western Sidney appear to suggest that you could keep your insulin levels at bay, if you mixed your sugary intra-workout supplement with aspartame-laden diet coke instead of water! The mechanism that's behind this phenomenon does yet still have to be elucidated.

You may be surprised to see a long headline, a long post and a couple of bullet points: "Looks like On Short Notice, reads like On Short Notice, but is not published on Saturday? What's that?" The answer to this question is easy. Lot's of interesting stuff I have come across as of late! And while some of them, like the study on the marginal utility of higher protein intakes on a diet would actually deserve their own post, I decided to give you the "long(er) version of a short notice" in order not to miss any of them... and yes, this means there is going to be more than today's news on the unexpected anti-insulinogenic effects of aspartame, the only partly expected outcomes of the US folic acid fortification program, the aforementioned protein study, the usefulness of spirulina, succinate and sucrose supplements for athletes and physical culturists and some brainy insights into a possible connection between low cholesterol, depression and suicide risk in men and women... ah, ok I see, you are already reading the aspartame item - well, go for it!

• The astonishing anti-insulin effects of intra-workout aspartame consumption Meanwhile even bodybuilders who are injecting and "supplementing" with all sorts of unquestionably unhealthy stuff are so afraid of the hitherto still rather vaguely established pro-carcinogenic effects of aspartame that supplement companies place huge stickers on the boxes of their products saying "ASPARTAME FREE!" Now, I am pretty sure that a recently published study that was conducted by scientists from the School of Science and Health at the University of Western Sydney in Campbelltown, Australia (Siegler. 2013), won't do much about that, but you will probably have to agree that it is still remarkable, to say the least, that the co-administration of an artificial sweetener which has not produced any glucose, insulin or whatever response in previous trials (cf. "Sweeter than your tongue allows") would do that!?

  

  Figure 1: While the mechanism is still unknown and the results need to be repeated in a second experiment, there is no question that the drop in insulin during the workout (see arrow(s)) which occurred during the carbohydrate + aspartame trial in the presence of identical glucose ingestion and blood glucose levels warrants further investigations (based on Siegler. 2013)

  During the four trials, which were separated by 7-10 days of rest, the 9 healthy, recreationally active males (age: 22±2 years; height: 180±9 cm; weight: 78.6±8.5 kg; participating in regular physical exercise at least twice per week) who had volunteered for this (in the eyes of some aspartame extremists, probably unethical undertaking ;-) cycled fasted for 60 minutes in a climate controlled laboratory. The only difference between the four sessions was the "intra-workout nutrition" the participants were fed, with...
  

  1. carbohydrate - 2% maltodextrin and 5% sucrose (figure 1, C),
  2. carbs + aspartame - 0.04% aspartame with 2% maltodextrin and 5% sucrose (figure 1, CA),
  3. water - plain water, only (figure 1, W), and
  4. aspartame + malto - 0.04% aspartame with 2% maltodextrin (figure 1, A)

  As it is common practice in studies like this, "all participants were instructed to follow the same diet and training schedule for the three days prior to each experimental trial." (Siegler. 2013, my emphasis)
  The respective intra-workout beverages were to be consumed in boluses of 4ml/kg body weight before and at 15-minute intervals throughout the trial. For the CHO groups this summed up to a total carbohydrate intake of 104.4±11.3g per participant and did - probably not to your surprise - cause a corresponding increase in insulin levels... with one exception, however: the intraworkout period in the CHO + Aspartame group (figure 1, red), when the insulin level dropped, during the exercise sessions and bumped back up to the same level as in the carbs only control afterwards (see figure 1).
  As the researchers point out, we do not yet have a mechanistic explanation for this phenomenon... nor can we even be sure that this was not some sort of strange artifact, so that
  

  "the disparity between insulin levels [does not only] warrant further investigation with a larger cohort of clinically relevant subject populations (e.g. metabolic syndrome, diabetes, etc.) [, but must also] be considered when designing nutrition-based, exercise intervention studies [in the future]" (Siegler. 2013

  That this observation could actually have very practical implications, both, in view of its potentially compromising effects on blood glucose levels in diabetics, where any insulin blocking effect of aspartame would probably reduce the already compromised glucose uptake even more, as well as in view of the anti-lipolytic (=blocks the release of fat from the cells) of insulin during a workout, which could actually be blocked with a minuscule amount of aspartame ... but alas, until the results have been confirmed and the mechanism behind this effect has been elucidated, what we are doing here is more or less intellectual masturbation - nothing to feel bad about, but still not the real deal ;-)

• 

  Figure 2: This is what the USDA expected to happen - more folic acid in food = higher intake (here in the elderly) = lower homocysteine levels; the reality looked pretty different, though, at least in adolescents the folic acid intake went up, but the homocysteine levels did not go down; moreover the B12 levels have declined as well... how much of this is related to confounding factors still has to be elucidated, but as of now it does not seem as if the fortification program was the success the USDA wanted it to be (Mc Bride. 2007).

  US adolescents and their "healthy grains" are now folic acid fortified, but are they also healthier? According to a study that has just been published in the Journal of Public Health, the great idea to put another artificial vitamin into our the food chain and fortify "healthy" cereal-grain products with folic acid, was so "successful" that the average US teen (14y at the time the fortification program began, 18y now) does now have 16% higher folate and 14% higher B6 concentrations.
  Instead of the expected decrease in homocysteine levels, of which scientists still believe that it plays in imminently important role in the development of heart disease, its serum levels did likewise increase by 17%, while the serum concentrations of vitamin B₁₂ decreased by 11 % post-fortification. The additional ~118 μg folate/d the subjects ingested from the fortified food products, appeared to be particularly useless (or even detrimental?) for boys / young men whose total homocysteine (tHcy) levels increased by 24%  to a much greater extent than in the girls / young women.
  Honestly, I don't really know what to make of these results at the moment, ... at least nothing better than to shake my head over the hilariousness of trying to turn junk(-food) into (good) food by simply enriching it with artificial vitamins. On the other hand, I am happy that even Daniel A. Enquobahrie and his colleagues feel that it is "warranted to investigate the significance of these improvements in folate status on clinical outcomes, in the post-fortification era." (Enquobahrie. 2013) - and that not just because the fortification program did not produce the desired results, but also because the folic acid intake already started to exceed the RDA in many of the subjects. This, and the alarming decrease in B12 levels of which Katherine L. Tucker had cautioned in the 2007 interview with Judy Mc Bride, already, that "better diagnosis for B12 deficiency should be given high priority"(Mc Bride. 2007) do not "warrant", imho, they rather make it imperative to follow the effect of this "nationwide health program" very closely.

• 

  Figure 3: The principle of relativity for protein based body recompositioning diets - When it comes to weight los, the word "high" in high protein diets must always be seen in the context of habitual protein intake and to whom we are comparing our dieters; or put simply: The average SAD dieter benefits from every gram, the average bodybuilder will hardly benefit from the 7th whey shake.

  Effectiveness of high(er) protein diets for weight loss depends on spread / change vs. baseline not on total protein intake That's basically how you could summarize the conclusion of the latest review of the existing data on the influnece of (high) protein intakes on changes in body composition by John D. Bosse and his colleagues from the University of Utah. To find out whether either the protein change (=high protein diets are only effective when the change in protein intake from baseline to intervention is large enough) or the protein spread theory (=those dieters within a cohort with the highest protein intake will see the most beneficial changes in body comosition) could explain the different outcomes of previous studies best, the researches collected an impressive dataset comprising 51 peer-review studies the analysis of which yielded the following two main results (Bosse. 2013):
  1. The 35 successful dietary interventions had on average 58.4% higher average protein intakes than those trials in which the authors had not been able to observe an additional beneficial of going high protein over the standard calorical restriction approach
  2. The 17 successful (=greater anthropomorphic changes than with calorie restriction alone) of the 25 studies, where the baseline protein intake of the subjects was available, the increase in protein intake was 28.6% (if you ate 100g protein per day before, that would mean you would eat 128.6g while you are dieting), minimal increases in 4.7% range, on the other hand, did not provide any additional benefit over energy reduction, alone.
  Overall, the review does therefore support the original hypothesis of the researchers that there are certain thresholds which have to be surpassed before dieters will see any benefits from an increase in protein intake. This does yet also mean, that for someone who is already eating 200g of protein on a daily basis, the addition of a protein shake with 20g of protein is probably not going to make so much of a difference as it would be way below the 28.6% change in protein intake, the protein change theory would prescribe (see [2] in the list above). As a matter of fact going higher and higher (e.g. like eating 300g of protein per day), will, if anything stall, not propel your progress, after all, there will be too little room for other nutrients, when you are already getting the lions share of your daily energy intake from protein... and NO you cannot lose weight without being in a caloric deficit, even if that is not readily calculable by the idiotic "calories-in-vs-calories-out" equation.
• The BMJ Supplement Review says: Thumbs up for sucrose, thumbs down for succinate and undecided  for spirulina In installment #36 of the A-Z of Nutritional Supplement Supplements, a series dedicated to review the pros and cons of purported ergogenic aids, the authors conclude that ...

  

  Figure 4: In view of the fact that the TCA or citric acid cycle is one of the #1 aerobic source of cellular energy (APT) and succinate is one of its intermediates it makes sense that supplementation could improve exercise performance, but hitherto this has not been confirmed.

  • ...the studies on spirulina fail to "study well-trained individuals", to use appropriate standardization regimen with relevance for physical culturists and athletes, identify the active ingredients and their effect on the antioxidant status, of which the respective scientists speculate that it would be the underlying mechanism of the observed ergogenic effects on chronic low-intensity exercise regimen
  • ...the research on succinate (only) supplementation is basically non-existent and claims with respect to its permanence enhancing effects is mostly based on theoretical considerations about its role in the TCA cycle 
  • ...despite the general trend within our society, where the overconsumption of sucrose (table sugar) is one of the major offenders to public health, "there may be value in, or at least room for, its inclusion in sports products targeting the provision of carbohydrate fuel during exercise"
  Nothing exciting, but a realistic and educative analysis, which has all the classic elements you should keep in mind, whenever you try to find out whether a product is worth its money: What research is there? What are the results? Are the positive results significant for me as a person? And... in the case of succrose: Could the use of this ergogenic aid be an obstacle for another goal of mine? I mean, you can benefit from guzzling tons of sugary drinks during your workouts, but if "looking good naked" is your primary goal and your performance only a means to an end - it is probably not wise to do so ;-)

• 

  Figure 5: Suicide risk in psychiatric patients /w (SA) or w/out (PS) prev. suicide attempt and surgical control (SC) in lowest, 2nd and 3rd cmp. to highest quartiles (Olié. 2011)

  Can pork brain in milk tell us something about suicide? Those of you who are on the SuppVersity Facebook news RSS channel will already know the image on the right. I only saw it today, but as Mark mentioned on my Facebook wall, he has used it (the image not the brain) in lectures before... be that as it may, that reminded me of an older study on the highly significant correlation between cholesterol levels and suicide attempts Emilie Olié and her colleagues observed in a 2010 study on the reliability of serum cholesterol levels as a predictor of the suicide risk in 3207 subjects [510 patients with a history of suicidal attempts (SA), 275 patients with no history of suicidal attempts (PC), and 2422 surgical controls (SC); Olié. 2011].
  The exact mechanism for the highly significant increase in suicide risk, esp. among women with previous suicide attempts in the lowest (1st quartile) is still not fully elucidated, Olié et al reference previous studies which suggest that low serum cholesterol levels, a "potentialmarker of central nervous systemcholesterol", impair the serotoninergic activity and" increase impulsivity" and thus precipitate to severe depression and the tendency and ability to pot a premature end to your life.
  In view of the fact that this and similar results were derived exclusively from analysis of psychiatric patients and considering that the cholesterol levels in the SA group were already significantly lower that in the PC and SC control (178±36 mg/dL vs. 217±43 mg/dL and 219±52 mg/dL, respectively) we should be very wary of transferring these results 1:1 to the "normal" people. 

I guess this is enough for today. After all, news are not so different than protein, it's the relative intake that makes all the difference - in other words: If I keep flooding you with those awesome posts, you won't appreciate each and every of them the same way you do now... and we don't want that to happen, do we? 

References:

• Bosse JD, Dixon BM. Dietary protein in weight management: a review proposing protein spread and change theories. Nutr Metab (Lond). 2013 Sep 12;9(1):81.
• Enquobahrie DA, Feldman HA, Hoelscher DH, Steffen LM, Webber LS, Zive MM, Rimm EB, Stampfer MJ, Osganian SK. Serum homocysteine and folate concentrations among a US cohort of adolescents before and after folic acid fortification. Public Health Nutrition. 2013; 15: 1818-1826.
• Mc Bride. Foods To Be Fortified With Folic Acid. USDA ARS. News. February 7, 2007. < http://www.ars.usda.gov/is/ar/archive/jun97/folate0697.htm > retrieved on September 14, 2013.
• Olié E, Picot MC, Guillaume S, Abbar M, Courtet P. Measurement of total serum cholesterol in the evaluation of suicidal risk. J Affect Disord. 2011 Sep;133(1-2):234-8.
• Siegler J, Howell K, Vince R, Bray J, Towlson C, Peart D, Mellor D, Atkin S. Aspartame in conjunction with carbohydrate reduces insulin levels during endurance exercise. J Int Soc Sports Nutr. 2013 Aug 1;9(1):36.
• Zemski AJ, Quinlivan RM, Gibala M, Burke LM, Stear SJ, Castell LM. A-Z of nutritional supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance: Part 36. Br J Sports Med. 2013 Sep;46(12):893-4.