Super Starches

Super Starches

Most of these are engineered starches created to have a very low if not totally absent glycemic response. From what I understand, they were originally created for people with the inability to utilize or store liver glycogen (glycogen storage disease); super starches promote steady blood glucose levels even in people who have no liver glycogen (sounds like me towards the end of a race).   

From a racing standpoint, the lack of glycemic response in theory should result in enhanced fat burning due to no/limited insulin signaling.  Interestingly/suprisingly, this has been supported by scientific data.  That being said, these are probably NOT good for recovery nutrition, where a large insulin spike is desired.  

I would suggest these products to be used as pre-race nutrition, while normal maltodextrin products would be fine during race as insulin is not as dominant during exercise (if you even have an insulin response) so the likelihood of insulin shutting down fat burning during exercise is minimal.  There seems to be real support this these products in the literature, and actually by researching this stuff I've nearly convinced myself to give it a try.

Nutrition products you may or may not have seen

Not endorsing any of this stuff.  I've been listening to a lot of triathlon podcasts, and those folks are very up to date on endurance nutrition products that might give them an edge.  So, why aren't ultrarunners?  It's an interesting difference between the two endurance camps.  Let's not argue about the respective difficulties, but appreciate that there are different approaches taken to the two different endeavors.

That being said, I have compiled and grouped several different classes of supplements that may be utilized or marketed to endurance athletes and just put my random (slightly scientific) thoughts in along with them.  I think they'll be published in this order.  If you can think of any other supplement groups that might be interesting, leave a comment or shoot me an email.

Before we start, I want to emphasize:  MORE IS NOT ALWAYS BETTER

1st - Natural Food Supplements (is that an oximoron?)
2nd - Amino Acid Supplements
3rd - Super Starches
4th - Oils

 Natural Food Supplements - Dehydrated food stuffs as well as isolated nutrients.  Usually chocked full of anti-oxidants including all the new ones such as polyphenols, isoflavonoids, catechins, and other plant phenols.  Generally speaking, the marketing behind these compounds is well ahead of the science, but there is at least some evidence that components in these products can be beneficial for endurance athletes.

Of the many compounds found in these products, the most compelling and consistent evidence supports the use of beetroot or beets in these products, as this contains nitrate, which acts on multiple systems which could enhance running performance.  Read more here:  Dietary nitrate and performance

Low calorie, but contains tons of nutrients.  Also should be a great source of nitrate which has been proven to increase endurance

Based on literature, a source of nitrate

Not sure what to say.  The publication on their website is definitely on the weak side of things.

A Quick Review of the Literature: Does caffeine enhance post-exercise recovery?

Debunked!

A very intriguing topic, often discussed in a wide range of magazines, from Men's Health, to Bicycling Magazine, to Runner's World.  As athletes we are constantly looking for methods to best refuel and rebuild our muscles after a difficult workout, and because caffeine has the ability to exert unique effects on metabolic machinery, it has constantly been a target for research.  One thing is fairly consistent throughout the literature, caffeine can improve exercise performance.  However, a quick google search revealed the above mainstream magazines touting the recovery-enhancing effects of caffeine, few of them addressed the fact that this is highly debated in the scientific literature (on a side note, the Bicycling magazine suggests incorporating 3.6 grams of caffeine per pound of body weight DO NOT DO THIS it is potentially lethal, I believe it is a type and they intended milligrams). 

            So, because I…  dislike overly simplistic one sided reporting of nutritional science, I have taken it upon myself to summarize recent scientific findings are available on the effects of caffeine on exercise recovery.  For the purpose of this summary is I will define recovery as increased glycogen synthesis, or increased activity of intracellular pathways associated with recovery, and finally altered secretion of hormones associated with the recovery process (insulin, IGF-1, testosterone, leptin, cortisol).

            Carbohydrates alone are not entirely sufficient to drive massive recovery when a person is near total glycogen depletion.  A plethora of data suggest that there is a platue on the efficiency of carbohydrates to fully drive recovery (1.2 grams of carbohydrates per kilogram of body weight per hour) as insulin levels will no longer increase, thus once carbohydrates are available in sufficient quantities, insulin levels tend  not increase further (1).  Similarly, and related, is the fact that once carbohydrates are available in sufficient quantities, muscle glycogen synthesis also plateaus.  Therefore, scientists have sought other nutritional strategies to further enhance muscle glycogen synthesis and/or muscle protein synthesis.  

            Although not universally supported (1), the addition of amino acids or protein to a carbohydrate rich recovery meal has been found to enhance insulin secretion, muscle protein synthesis, and in some cases also enhance muscle glycogen synthesis compared to carbohydrates alone (2-5).  Thus, this is the “Gold Standard” when it comes to recovery nutrition.  But I digress.

Interestingly, at rest, caffeine is known to have negative effects on glycemic control exerted by muscles (6, 7).  That is to say, caffeine diminishes the ability of muscles to respond to insulin signals to store glucose (carbohydrate).  However, this is at least partially abolished during and after exercise (6, 8, 9).  So then, does caffeine have a role in recovery?  In 2008, Pedersen and colleagues (10) said yes, and cited the fact that in their study they observed blood glucose levels to be elevated for a longer period of time in the group receiving carbohydrates + caffeine than compared to a group receiving only carbohydrates during the recovery phase.  This was further supported by their observation that glycogen synthesis rates were significantly higher in the carbohydrate + caffeine group 4 hours post exercise.  While the authors are unable to identify a mechanism for this observation, they speculate that this is achieved through increased intestinal glucose transport.  Based on this one result, indeed, there is some evidence to suggest caffeine may enhance recovery, if consumed with carbohydrates for 4 hours post exercise.  

However, this one study is somewhat of an outlier when looking at the entire breadth of work done on this topic.  In a more recent study performed based on the article published by Pedersen et al. using identical quantities of caffeine and carbohydrate, there was no difference in post-exercise blood glucose or insulin levels when comparing the group that received carbohydrates to the group that received carbohydrates + caffeine (11).  Furthermore, a study published in 2012 (perhaps the most complete study to date) which compared carbohydrates + caffeine, carbohydrates + protein, and carbohydrates alone, found that caffeine had no effect on muscle glycogen synthesis rates (12).  Furthermore, this study also investigated whether caffeine ingestion post-exercise increases intestinal sugar transport, and found that there was no change in the capacity of the intestines of their subjects (elite cyclists) to transport sugar (12).  

Indeed, these results are quite contradictory, and the positive results received much more attention from the media than did the negative/no effect results.  Perhaps one of the most overlooked differences between the 2012 study done by Beelen et al. and the 2008 Pedersen study, was the amount of carbohydrate supplied during the post-exercise window.  Study participants in Pedersen’s study received 1 gram of carbohydrates per kilogram of body weight per hour, while participants in the 2012 Beelen study received 1.2 grams of carbohydrates per kilogram body weight per hour.  This would indicate that athletes in the Pedersen study received a lower dosage of carbohydrate than those in the Beelen study.  Therefore, I believe this may be an explanation for the differences between these results.  

Further interpretation of these results can be that caffeine may enhance recovery when glucose (carbohydrates) are available in insufficient quantities.  I think that rarely do I consume the truly adequate amount of carbohydrates within the appropriate time frame to fully maximize glycogen synthesis (1.2 grams of carbohydrates per kilogram body weight per hour).  For me that would be approximately 80 grams of carbohydrates per hour.  Usually I grab a chocolate milk or Gatoraide that may contain roughly 60 grams of carbohydrates.  In this case, carbohydrates alone may be insufficient to fully maximize recovery, and coingestion of caffeine could have a beneficial effect.  However, if carbohydrates are available in sufficient quantities, I believe (IMHO) caffeine ingestion will NOT enhance recovery, and because of the known ways in which caffeine diminishes insulin action, there is too much risk it may hamper recovery.  

Overall, the rate at which glycogen is synthesized after a hard workout depends on a huge number of factors.  For example, length and duration of the workout, total hydration status (which can effect gastric emptying), the level of glycogen depletion, insulin sensitivity, as well as hormones, can all significantly effect rates of glycogen synthesis.  

              

Works Cited

1.         Howarth KR, Moreau NA, Phillips SM, Gibala MJ. Coingestion of protein with carbohydrate during recovery from endurance exercise stimulates skeletal muscle protein synthesis in humans. J Appl Physiol. 2009 Apr;106:1394-402.

2.         van Loon LJ, Saris WH, Kruijshoop M, Wagenmakers AJ. Maximizing postexercise muscle glycogen synthesis: carbohydrate supplementation and the application of amino acid or protein hydrolysate mixtures. Am J Clin Nutr. 2000 Jul;72:106-11.

3.         van Loon LJ, Saris WH, Verhagen H, Wagenmakers AJ. Plasma insulin responses after ingestion of different amino acid or protein mixtures with carbohydrate. Am J Clin Nutr. 2000 Jul;72:96-105.

4.         Berardi JM, Price TB, Noreen EE, Lemon PW. Postexercise muscle glycogen recovery enhanced with a carbohydrate-protein supplement. Med Sci Sports Exerc. 2006 Jun;38:1106-13.

5.         Ivy JL, Goforth HW, Jr., Damon BM, McCauley TR, Parsons EC, Price TB. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. J Appl Physiol. 2002 Oct;93:1337-44.

6.         Thong FS, Derave W, Kiens B, Graham TE, Urso B, Wojtaszewski JF, Hansen BF, Richter EA. Caffeine-induced impairment of insulin action but not insulin signaling in human skeletal muscle is reduced by exercise. Diabetes. 2002 Mar;51:583-90.

7.         Robinson LE, Savani S, Battram DS, McLaren DH, Sathasivam P, Graham TE. Caffeine ingestion before an oral glucose tolerance test impairs blood glucose management in men with type 2 diabetes. J Nutr. 2004 Oct;134:2528-33.

8.         Yeo SE, Jentjens RL, Wallis GA, Jeukendrup AE. Caffeine increases exogenous carbohydrate oxidation during exercise. J Appl Physiol. 2005 Sep;99:844-50.

9.         Battram DS, Shearer J, Robinson D, Graham TE. Caffeine ingestion does not impede the resynthesis of proglycogen and macroglycogen after prolonged exercise and carbohydrate supplementation in humans. J Appl Physiol. 2004 Mar;96:943-50.

10.       Pedersen DJ, Lessard SJ, Coffey VG, Churchley EG, Wootton AM, Ng T, Watt MJ, Hawley JA. High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine. J Appl Physiol. 2008 Jul;105:7-13.

11.       Taylor C, Higham D, Close GL, Morton JP. The effect of adding caffeine to postexercise carbohydrate feeding on subsequent high-intensity interval-running capacity compared with carbohydrate alone. Int J Sport Nutr Exerc Metab.  Oct;21:410-6.

12.       Beelen M, Kranenburg J, Senden JM, Kuipers H, Loon LJ. Impact of caffeine and protein on postexercise muscle glycogen synthesis. Med Sci Sports Exerc.  Apr;44:692-700.

BCAA and the CNS Fatigue Hypothesis

An elegant hypothesis with limited laboratory support

(In my humble opinion)

            What is bonking I ask?  As participation in marathons, triathlons, and other endurance endeavors increases this question becomes more pertinent (a recent survey by Running USA suggested that over 500,000 people completed a 26.2 mile marathon in 2010, a 9.9% increase over the number in 2009).  Also known as exercising to exhaustion or “hitting the wall,” the idea of fatigue resulting in failure to maintain a desired pace that sets in late in a long event has been an interesting concept for nutritionist as well as exercise physiologists.  The short answer to the question is that we don’t know exactly what results in “bonking.” 

            The long answer is that this is probably the result of several metabolic changes resulting in fatigue.  While most acknowledge that muscle glycogen depletion and lactate accumulation contribute to peripheral fatigue, they do not fully explain the induction of fatigue during sub-maximal exercise such as endurance events or high altitude climbing (1).  One prevailing hypothesis is that exhaustion is regulated by the central nervous system (CNS). Peripheral biochemical changes that occur during exercise influence the CNS, resulting in failure to recruit more skeletal muscle and reduced performance.  One peripheral biochemical change resulting in CNS fatigue is hypoglycemia due to liver glycogen depletion.  In this respect, carbohydrate intake is thought to attenuate CNS fatigue by maintaining blood glucose levels (2).  Interestingly, another cause of CNS fatigue is thought to be increasing concentrations of serotonin or 5-hydroxy-tryptamine (5-HT) in the brain which is derived from the large neutral amino acid tryptophan.  The neurotransmitter 5-HT is known to play a role in sensory perception, depression, sleepiness and mood, making it a likely candidate for the CNS fatigue hypothesis (3).

            While BCAAs are metabolized by skeletal muscle during prolonged exercise, they also compete with free tryptophan for uptake across the blood brain barrier (BBB) by L-type amino acid transporters.  However, as endurance exercise continues, skeletal muscle increasingly oxidizes BCAAs, diminishing the plasma BCAA pool, which reduces competition with tryptophan for transport across the BBB (3).  A unique amino acid, tryptophan is the only amino acid that binds albumin in plasma (4).  Indeed, under normal circumstances, approximately 90% of plasma tryptophan is bound to albumin (3).  However, as muscle and liver glycogen stores are depleted, free fatty acids are released to support metabolic demands.  In turn, free fatty acids bind albumin, resulting in competition for binding sites on albumin with tryptophan (4).  This results in an increase in unbound tryptophan that can be transported across the BBB. 

            Thus it is hypothesized that by increasing BCAA consumption during endurance exercise one might be able to attenuate CNS fatigue by increasing competition with tryptophan for transport to the brain. Despite the elegant science behind this hypothesis, data regarding the efficacy of this approach appears to be limited.  A field trial reported increased mental performance in trained runners consuming BCAAs during a 30km competitive event (5).  Interestingly, this has not been replicated in well controlled laboratory conditions (6).  Similarly, consumption of an isocaloric solution containing BCAAs and carbohydrate did not influence the time to exhaustion in glycogen depleted cyclists compared to those consuming carbohydrate alone (7). 

One important caveat is that consumption of exogenous carbohydrates is a must for endurance athletes.  It has been shown that consumption of carbohydrates diminishes the release of free fatty acids, in turn influencing the amount of free tryptophan in plasma that results from prolonged exercise, possibly negating any benefit derived from BCAA consumption (8).  Furthermore, large doses of BCAAs can increase the ammonia concentration in plasma due to their metabolism resulting in the release of nitrogen, requiring buffering by TCA cycle intermediates, which could lead to early fatigue in working muscles (9).  It is entirely possible that by consuming BCAAs during exercise one is able to offset the effects of CNS fatigue, only to increase peripheral fatigue (9).  It is also important to point out that the hypothesis discussed in here does not take into account the role of BCAAs in supplementing skeletal muscle metabolism.  In summary, while combating CNS fatigue with BCAAs is certainly an intriguing nutritional intervention, there seems to be limited laboratory data supporting its efficacy.   

This leads me to share my feelings on laboratory science and the nature of ultra-endurance sports.  To me, it seems as though it is nearly impossible to replicate a true ultra event in the laboratory.  Whether it be due to ethical concerns, athletic desire, or simply lack of a truely difficult labortaory training environment, I feel it is hard to re-create the extreme conditions an ultrarunner might face.  Heat, alititude, mud, 15-16+ hours of running, sleep deprivation, hypothermia, all these are very difficult to recreate.  In this aspect when considering nutritional interventions for sport, I try very hard to fully grasp the science behind the supplement.  Nutrition, in particular can be masked by many variables, and in the end may only result in a 1% improvement which in the end may missed due to the insane number of variables that go into exercise performance.  Based on these observations, I look for what is called Biological Plausibility - does the supplement have a large amount of molecular and biochemical support, even if the observations on performance gains in humans or animal models are limited?   In the case of BCAA in limiting CNS fatigue, I think yes!

Works Cited

1.         Noakes TD, St Clair Gibson A, Lambert EV. From catastrophe to complexity: a novel model of integrative central neural regulation of effort and fatigue during exercise in humans: summary and conclusions. Br J Sports Med. 2005 Feb;39:120-4.

2.         Karelis AD, Smith JW, Passe DH, Peronnet F. Carbohydrate administration and exercise performance: what are the potential mechanisms involved? Sports Med.  Sep 1;40:747-63.

3.         Blomstrand E. A role for branched-chain amino acids in reducing central fatigue. J Nutr. 2006 Feb;136:544S-7S.

4.         Curzon G, Friedel J, Knott PJ. The effect of fatty acids on the binding of tryptophan to plasma protein. Nature. 1973 Mar 16;242:198-200.

5.         Hassmen P, Blomstrand E, Ekblom B, Newsholme EA. Branched-chain amino acid supplementation during 30-km competitive run: mood and cognitive performance. Nutrition. 1994 Sep-Oct;10:405-10.

6.         Cheuvront SN, Carter R, 3rd, Kolka MA, Lieberman HR, Kellogg MD, Sawka MN. Branched-chain amino acid supplementation and human performance when hypohydrated in the heat. J Appl Physiol. 2004 Oct;97:1275-82.

7.         van Hall G, Raaymakers JS, Saris WH, Wagenmakers AJ. Ingestion of branched-chain amino acids and tryptophan during sustained exercise in man: failure to affect performance. J Physiol. 1995 Aug 1;486 ( Pt 3):789-94.

8.         Blomstrand E, Moller K, Secher NH, Nybo L. Effect of carbohydrate ingestion on brain exchange of amino acids during sustained exercise in human subjects. Acta Physiol Scand. 2005 Nov;185:203-9.

9.         Davis JM, Alderson NL, Welsh RS. Serotonin and central nervous system fatigue: nutritional considerations. Am J Clin Nutr. 2000 Aug;72:573S-8S.