Saturday, April 6, 2013

Leucine & HMB - Similar, Yet Different. BCAA, B6 & NAFLD - It's About Ratios. Eccentrics, Mitochondria & GLUT-4 - No Pain, No Fat Gain. Fiber & Diabesity - Useful, But Not Magic.

"Potatoes" have the "pot-" from "potassium" not just in their name, they also got plenty of it in them. A medium sized potato (147g) contains 926mg of highly bioavailable potassium and covers ~26% of your daily requirements... and no, normal potatoes are not pro-diabetic unless you over-process them (learn more in the Potato Manifesto)
5.93 mm and 3.7 millimeters those are the SuppVersity Figures of the Week and the average heights by which the systolic and diastolic blood pressure of dropped in 21 controlled trials in the course of which the subjects simply increased their daily potassium intake (Aburto. 2013). Results like these, which were published in the latest issue of the British Medical Journal rarely make it to the mainstream news and if they do than just as a marginal note to the paradigmatically blinded message that we all had to dramatically reduce our salt intakes if we did not want to end up in the emergency room.

Now, aside from the fact that Maillott et al. have demonstrated only recently, that "the 2010 Dietary Guidelines for sodium were incompatible with potassium guidelines and with nutritionally adequate diets, even after reducing the sodium content of all US foods by 10%" (Mailott. 2013), both a dramatic reduction in salt and significant increase in potassium intake could be achieved if people simply stopped eating convenient, but blatant and thus salt- and sugar-laden products of the food industry and bought fresh products instead.

Leucine and HMB both work, but they work via different pathways / mechanisms.

If you want to learn more about the usefulness of HMB, check I suggest take (another) look at my article about the results of a 2012 dissertation (read more)! And in case you feel you need to learn more, browse the SuppVersity archive for the key-words leucine and HMB and educate yourself.
(Wilkinson. 2013) A group of researchers from the UK and Canada has recently found that "leucine (Leu) possesses the most marked anabolic characteristics in acting as a trigger element for the initiation of protein synthesis". In that it is even superior to its best-known metabolite β-hydroxy-β-methylbutyrate (HMB), which has a 40% less pronounced stimulatory effect on protein synthesis (110% leucine; 70% HMB; after oral supplementation).

The reason it may still have merit to supplement with (additional?) HMB is its non-insulin depended effects on skeletal muscle breakdown (-57%), which would up the rate of protein retention, i.e. the difference of protein synthesis (70%) and protein breakdown (-57%) to 127% and should thus result in superior net gains in skeletal muscle protein compared to pure leucine.

Bottom line: Whether you actually "need" HMB, is a whole different question, though. After all studies comparing a simple 30g whey protein shake and an HMB supplement are missing and whether the addition of HMB to the whey would yield benefits is questionable. Doing just that with leucine has, after all, already been shown not to yield any additional benefits.

Fatty liver from 50%+ of the currently available dietary supplements? 

(Kaimoto. 2013) If we go by the results of a soon-to-be-published rodent study from Japan the chronic consumption of BCAA containing supplements could in fact result in an increased hepatic lipid and cholesterol deposition and would thus pave the way to non-alcoholic fatty liver disease (Kaimoto. 2013).
Figure 1: Changes in body composition & organ weight, serum and liver measures after 21 days on BCAA (BCAA(+)) and/or pyridoxin (B6(+)) enriched diets (Kaimoto. 2013)
If you take a look at the data in figure 1, you will yet also realize that the triglyceride and cholesterol deposition in the liver the scientists observed, when the rats were fed with a show that contained comparatively low supplemental amounts of 2%, 1.5% and 1.25% leucine, valine and isoleucine and thus the human equivalent of ~3-4g of BCAAs, was ameliorated when the diet contained sufficient amounts of vitamin B6 aka pyridoxin. Since the corresponding human equivalent dosages for B6 were ~3-4x higher than the RDA of 1.3mg/day but still way below the amount of B6 almost every currently available BCAA supplement contains, you probably don't have to worry about fatty liver or a shrinking thymus and compromised immune system.

Tired, exhausted, had to cut your workout short today? Is it the flu, or just too much BCAAs?
As a seasoned SuppVersity reader you will however be aware that the hailed anti.catabolic muscle builder is by no means free of nasty side effects, when consumed in excess - suggested reads:
  • High Dose BCAA Supplementation Can Inhibit Serotonin Metabolism & Cause Anxiety (read more)
  • Chronic High Dose BCAA Supplementation Reduces Endurance Performance by 43% Plus: How Ammonia, Glutamine, Arginine & Low Carbing Could be Involved (read more)
If you want to know more about the established benefits of leucine, valine and isoleucine, I suggest you simply go through the archives and pick whatever yo are interested in.

Bottom line: The latest BCAA news don't negate their established ergogenic effects, but they do support the notion that the "more is more" and "better take them with every meal" principles are not worth following - even if you get your BCAAs for free, by the way.

More dietary fibre lovin' ... but rightly so?  

(Dall'Alba. 2013) A recent study from the Universidade Federal do Rio Grande do Sul in Brazil confirms that the consumption of additional 10g of soluble dietary fiber (/-re) in the form of partially hydrolysed guar gum can have beneficial effects on some of the markers of metabolic syndrome.
Figure 2: Relative changes compared to baseline in 44 patients with type 2 diabetes (males 38·6 %, mean age 62 years, diabetes duration 14.2y) after 4 and 6 weeks on diets w/ or w/out 10g of additional guar gum (Dall'Alba. 2013)
The results of the study (figure 1) do yet also show that the benefits are modest at best. Even the statistically highly significant increase in HDL after 6 weeks on the guar gum diet is not necessarily physiologically relevant and if it was not for the higher baseline energy intake in the supplementation group, and the greater reduction in HbA1c (indicating a better blood glucose stability), you could even argue that the addition of the 10g/day of dietary fiber was totally useless (suggested read: previous articles about fiber).

Bottom line: While dietary fiber has its merit. It's not much different from veggies. If you just add it / them on top of you junkfood diet, the effects you can expect are modest - if not non-existent.

Eccentric exercise it's not all productive that induces damage

More reasons for a GLUT-4 boosting EAA smoothie post workout (learn why)
(Magalhães. 2013) According to a study that has been published ahead of print in the online version of the Journal of Applied of Physiology, eccentric exercise (downhill running) did not jst lead to highly significantly increases in plasma creatine kinase activity, myoglobin and interleukin-6 content of the muscle of 12-week old mice, it also impaired state 3 and respiratory control ratio of the mitochondria and increased their susceptibility to mitochondrial permeability transition pore (MPTP) which can lead to cell sqelling and eventually cell death. Accordingly, Mangalhães et al. observed an increase in cell swelling amplitude, lower time to maximal swelling velocity, and calcium release immediately after the end of exercise annd conclude that
"prolonged EE [eccentric exercise] transiently impaired mice skeletal muscle mitochondrial function and increased susceptibility to calcium-induced MPTP opening"
Now you can certainly argue that this is the necessary training effect your cells need in order to adapt, in view of previous findings from human studies (just randomly selected examples, here)...
  • Figure 3: Glycogen snythase  (in mmol/mg protein per min) 4h after postexercise (10 x 10 eccentric or concentric isokinetic leg extensions after previous glucose depleting cycling exercise) carbohydrate feeding depening on G6Pase levels (Doyle. 1993)
    -37% reduction in insulin-mediated glucose disposal rate in 6 healthy, but untrained men after 30min downhill running (Kirwan. 1992)
  • -11% reduced glucose uptake and glucose necessary to maintain euglycemia during maximal insulin stimulation, as well as -39% lower basal = non-insulin triggered GLUT-4 expression and in seven healthy subjects even 48h after one-legged eccentric exercise (Asp. 1996)
  • significantly reduced glycogen synthase after eccentric vs. concentric training in ten moderately trained subjects after 10 sets of 10 repetitions of either concentric or eccentric contractions in opposite legs and the ingestion of 0.4g carbohydrate/kg body wt every 15min (Doyle. 1993; see figure 3).
... you should yet reconsider to which extend the "no pain no gain" principle is going to yield the healthy lean mass and performance gains you are probably looking for.

Bottom line: While the broscientific wisdom "You won't grow, if you're training like a puss'!" may have its limited merit, the equation "maximal damage = maximal growth" many of the bros derive from this supposition is not just unsustainable and counterproductive, but potentially unhealthy and fattening.... How's that? Just imagine bulking while you are constantly insulin resistant for daily eccentric exercise.



Aside from the obligatory Facebook news that's it for today's installment of On Short Notice!  So once, you've checked out the following news over @ www.facebook.com/SuppVersity ...
    Aside from coffee and nutrition in general, vitamin A is another potential regulator of the peripheral  (non-light regulated) circadian clock - especially in the liver (learn more)
  • Some light exercise can shed some heavy fat -- Weight loss success of healthy, but sedentary women demonstrates: as long as you are not fixated on what the scale says you will be surprised by how powerful even moderate physical activity is (read more
  • Treating type I diabetes with GABA -- In a 2011 rodent study the administration of the amino acid and neurotransmitter helped repair damaged pancreatic beta cells (read more)
  • Undereating + (over-)training is the most effective endocrine disruptor -- At least among natural stressors, the aforementioned combination is far "superior" to regular stress (read more)
  • Don't forget about vitamin A -- Scientists identify the mechanism behind the anti-Alzheimer's effect of retinoic acid (read more).
...it's high time to get your behind off the couch or computer chair and enjoy a well-deserved active and social, yet regenerative weekend.

References:
  • Aburto NJ, Hanson S, Gutierrez H, Hooper L, Elliott P, Cappuccio FP. Effect of increased potassium intake on cardiovascular risk factors and disease: Systematic review and meta-analyses. BMJ 2013;346:f1378.
  • Asp S, Daugaard JR, Kristiansen S, Kiens B, Richter EA. Eccentric exercise decreases maximal insulin action in humans: muscle and systemic effects. J Physiol. 1996 Aug 1;494 ( Pt 3):891-8.
  • Dall'Alba V, Silva FM, Antonio JP, Steemburgo T, Royer CP, Almeida JC, Gross JL, Azevedo MJ. Improvement of the metabolic syndrome profile by soluble fibre – guar gum – in patients with type 2 diabetes: a randomised clinical trial. British Journal of Nutrition. April 2013. [Epub ahead of print]
  • oyle JA, Sherman WM, Strauss RL. Effects of eccentric and concentric exercise on muscle glycogen replenishment. J Appl Physiol. 1993 Apr;74(4):1848-55.
  • Kaimoto T, Shibuya M, Nishikawa K, Maeda H. High Incidence of Lipid Deposition in the Liver of Rats Fed a Diet Supplemented with Branched-Chain Amino Acids under Vitamin B6 Deficiency. J Nutr Sci Vitaminol (Tokyo). 2013;59(1):73-8.
  • Kirwan JP, Hickner RC, Yarasheski KE, Kohrt WM, Wiethop BV, Holloszy JO. Eccentric exercise induces transient insulin resistance in healthy individuals. J Appl Physiol. 1992 Jun;72(6):2197-202.
  • Magalhães J, Fraga M, Lumini-Oliveira J, Gonçalves I, Costa M, Ferreira R, Oliveira PJ, Ascensãoa A. Eccentric exercise transiently affects mice skeletal muscle mitochondrial function. Applied Physiology, Nutrition, and Metabolism, 10.1139/apnm-2012-0226. 
  • Maillot M, Monsivais P, Drewnowski A. Food pattern modeling shows that the 2010 Dietary Guidelines for sodium and potassium cannot be met simultaneously. Nutr Res. 2013 Mar;33(3):188-94.
  • Wilkinson DJ, Hossain T, Hill DS, Phillips BE, Crossland H, Williams J, Loughna P, Churchward-Venne TA, Breen L, Phillips SM, Etheridge T, Rathmacher JA, Smith K, Szewczyk NJ, Atherton PJ. Effects of Leucine and its metabolite, β-hydroxy-β-methylbutyrate (HMB) on human skeletal muscle protein metabolism. J Physiol. 2013 Apr 3.