Tuesday, April 23, 2013

Citrulline as Substrate Switch. Galactose as Workout Fuel, Glycogen Repletion Not Urgent, 2x a Day 6x a Week = Too Much For Your Antioxidant System, Astaxanthin For IgA

Actually it's not the burn during the workout that matters, but I don't have to tell you that, do I? (pic i-am-beast.com)
What do you do with a whole host of interesting exercise-related nutrition news that are piling up in your archive, but are too good to be "burned" as short links with one sentence of text on the SuppVersity Facebook Wall?

Right! You compile all those news into a potpourri, attach the label "SuppVersity News Potpourri" to it and blow them out in a blogpost of their own. A post that covers the whole peri-workout window as well as the short-/long-term effects on exercise on your anti-oxidant and immune system.

Sounds good? Well, then go ahead...
  • Immediate post-workout glycogen repletion in endurance athletes probably useless (Carlsohn. 2013) While the hormonal response and the long-term effects of running around with depleted glycogen levels are a totally different animal, the latest research from the University Outpatient Clinic Potsdam in Potsdam, Germany, clearly suggests that the immediate post-run glycogen-repletion with 1.5g/kg body weight of fast acting carbs per hour is useless...

    Do you remember my "Glycogen-free muscle growth" post(s) from 2011?
    ...at least with respect to the 5,000m running performance of the twelve recreational runners (4m/8w; 1.73 ± 0.11 m, 69.1 ± 13.4 kg). who were involved in Carlsohn et al.'s study.
    "Running time during 5,000-m time trials did not differ between bTT (1,305 ± 140 s), following CARB (1,276 ± 125 s) or PLA (1,285 ± 124 s, p= .85). There were no differences in RPE (bTT 18.3 ± 0.3, CARB 18.7 ± 0.3, PLA 18.8 ± 0.9; p= .48), bLa/min, PLA 187 ± 3 beats/min; p= .96).
    In view of these results it should actually not necessary to formulate a "bottom line", but alas...

    Bottom line: "[T]he rationale of recommending immediate carbohydrate intake following exhausting exercise to 5,000-m runners might be questioned" (Carlsohn. 2013). Please keep in mind though that not repleting your glycogen stores at all is not an option - the myth that's been partially busted by the study at hand is that you must do that as fast as possible to maintain maximal performance - not that you must do it at all. 
  • "High" galactose foods ?
    Fermented yoghurt1.30g
    Beets, canned, regular pack, solids and liquids0.80g
    Celery, raw0.66g
    Cherries, sweet, raw0.59g
    Bockwurst, pork, veal, raw0.48g
    Corn, sweet, yellow, canned, whole kernel, drained solids0.36g
    Beans, navy, mature seeds, raw0.34g
    Snacks, pretzels, hard, plain, salted0.22g
    Spices, curry powder0.21g
    Spices, mustard seed, yellow0.20g
    Spices, paprika0.19g
    Babyfood, fruit, plums with tapioca, without ascorbic acid, strained0.19g
    Spices, ginger, ground0.19g
    Spices, basil, dried0.19g
    Kiwi fruit, (chinese gooseberries), fresh, raw0.17g
    Cereals, oats, instant, fortified, plain, prepared with water (boiling water added or microwaved)0.16g
    Cheese, mozzarella, whole milk0.15g
    Spices, cloves, ground0.15g
    Cheese, parmesan, grated0.15g
    Spices, oregano, dried0.15g
    Fast foods, cheeseburger; single, regular patty, with condiments0.15g
    Plums, raw0.14g
    Peas, green (includes baby and lesuer types), canned, drained soilds, unprepared0.14g
    Cereals, oats, instant, fortified, plain, dry0.13g
    Fish, fish portions and sticks, frozen, preheated0.13g
    Figs, dried, uncooked0.13g
    Babyfood, plums, bananas and rice, strained0.12g
    Egg, whole, raw, fresh0.11g
    Avocados, raw, all commercial varieties0.10g
    Crackers, saltines0.07g
    Snacks, tortilla chips0.07g
    Egg, white, raw, fresh0.07g
    Snacks, tortilla chips, nacho cheese0.07g
    Peaches, raw0.06g
    Melons, cantaloupe, raw0.06g
    Galactose as alternative workout fuel (Duckworth. 2013) - A recent study from the Leeds Metropolitan University in the UK demonstrates that
    "ingesting a solution containing galactose before and during exercise can positively affect postexercise satiety and energy balance throughout the day, compared to a more readily available and widely consumed form of carbohydrate" (Duckworth. 2013)
    The scientists conclude that based on the observations they made, when they provided nine recreationally active eumenorrheic females (mean age 22y; weight 63.3kg) with either 45g galactose (GI~20) or glucose (GI~89) drinks prior to (300 ml) and at every 15 min during a low intensity steady state jog at 65% of their VO2Peak
    Note: I guess, it goes without saying that 45g of galactose this is more galactose than you can stomach from ingesting any "high galactose" foods; see table on the right, data in g/100g).
    The scientists measured the substrate oxidation, postexercise satiety and subsequent energy intake on three occasions (GLU, GAL, placebo) and found that
    • the plasma glucose levels were significantly greater throughout the exercise and in the rest period, when the subjects ingested the glucose drink,
    • there were no differences in carbohydrate oxidation, and
    • perceived hunger was significantly lower throughout the galactose compared to both the glucose and placebo trials
    What may yet be most significant for the average trainee trying to shed some weight is the difference in net energy balance, i.e. the difference between energetic costs of the workout, on the one hand, and the energy intake from the glucose / galactose supplement and the food intake during the post-exercise ad-libitum test lunch and the remainder of the day, which was negative only in the placebo and the galactose trial.
    Bottom line: If you want to shed some body fat and cannot go without an intra-workout beverage pick galactose over glucose, but do a "test run" before you try that in public - the monosaccharide is notorious for its socially not acceptable effects on the evaporations from your gastrointestinal tract ;-)
    "Does the Usefulness of Vitamin E Supplementation Depend on Your Activity Level?" It is possible that only those benefit who are already overtaxing their system and will thus need additional protection (learn more)
  • Exercise is stressing, but the long-term results are what's associated with improved antioxidant capacity (Lundström. 2013) The data Lundström et al. have collected in their recent 3-week trial involving fourteen 26-year-old volunteers who performed two "strenuous" (intensity targeted to 75% of VO2max) endurance training sessions per day (6 days a week) does in a way underline the validity of the hormesis hypothesis. Despite the fact that the increase in oxidative stress in response to the the allegedly hefty (for non professional athletes) two-sessions a-day, 6-days a week was not significant, the latter was facilitated / buffered by highly significant declines in the total plasma antioxidant capacity (AO).

    However, aside from the fact that the AO levels did not fully return to baseline after the subsequent 4-week recovery period, the most intriguing results of the study at hand is the highly significant negative (meaning "if A is high, B is low") correlation between fat-free mass and oxygen uptake, on the one hand, and oxidation stress, on the other.
    Bottom line: With both of the former, i.e. fat-free mass and oxygen uptake while you exercise, being hallmark features of physical fitness you cannot increase without working out, the balancing act, every trainee has to master is to find the exact i +1 load of stress that allows for adequate recovery and super-compensation in the time to the next workout / mesocycle.
  • Low Immunoglobuli, high cortisol and health While there appears to be a general relation between suppressed sIgA and high cortisol levels, on the one hand, and ill-health effects on the other. The latter is not sports-specific (Volkmann. 2006), and elite athletes are, despite suppressed IgA levels capable of normal responses to novel oral vaccinations, "indicating that mucosal immune mechanisms are intact" (Gleeson. 2000).
    Astaxanthin supplementation can ameliorate minor sIgA dump in athletes (Baralic. 2013) Study shows, supplementation with 4mg/day of astaxanthin can ameliorate the decrease in sIgA (marker of immune health) in young soccer players following 2h of exercise.

    There are yet two things you have to consider, when you read studies like these:  (a) Scientific evidence of the significance of immunoglobolin measures is not fully conclusive, and (b) the changes placebo group were not even significant.
    Note: In view of the fact that "[t]he clinical significance of [immunoglobolin changes] in acquired immunity with acute exercise and training remains unknown" (Walsh. 2011), the scientists' conclusion that "astaxanthin supplementation might serve as a countermeasure to sIgA changes associated with continuous intense training", must be taken with some caution wrt to its real-world benefits. 
  • Citrulline shifts substrate utilization towards carbs (Faure. 2013) With this last item in today's Exercise Science Potpourri, we are actually coming back to the an issue that has been in the SuppVersity news pretty regularly as of late: the amount fat / glucose you burn during a workout. I guess, I have made my personal perspective that fatty acid oxidation rates during exercise are hilariously overrated pretty clear. This does yet not stop me from pointing you towards the results of a soon-to-be-published study from the Université Paris Descartes the results of which would suggest that supplemental citrulline could work as a "fuel switch".

    Do you remember the December 2011 SuppVersity news on citrullines anti-catabolic effects (go back!)
     The significant downregulation of oxidative enzymes from the Krebs cycle and mitochondrial respiratory chain, the French scientists observed in a group of male Sprague-Dawley rats, when theyy re-fed them after a 12-week period of dietary restriction with a citrulline supplemented diet (+5g/kg chow and thus equivalent to what human studies have been using) compared to the standard chow with an iso-caloric mix on non-essential amino acids added) would at least suggest that "citrulline supplementatio [...] seems to induce a switch in muscle energy metabolism, from aerobia towards anaerobia" (Faure. 2011).

    Now, I did already point out that this is not necessarily a bad thing, but they cannot - as you may speculate now - explain the beneficial effects the original NO-supplement ingredient l-arginine on blood glucose management (learn more), because Faure et al. were able to show that "citrulline action is not direct and is not related to arginine" (Faure. 2013).
    Figure 1: Activity of enzymes involved in the oxidation of fatty acids; data expressed relative to baseline levels  on ad-libitum diet (Faure. 2013)
    Against that background another effect that was brought about by the high citrulline diet could yet be even more of a major metabolic disadvantage: The increase in metabolically highly glucoes guzzling unflexible type-IIb fibers (see figure 1; learn more), which has been associated with low / non-existent adiponectin levels by Krause et al. (2008).
    We have to be careful though, with respect to the interpretation and potential implications of these results. Why? Well, there are actually countless reasons: (a) Human beings are no rodents and normal rodents are no athletes, (b) the potential impact of a higher baseline protein intake or the absence of the calorie restriction before the supplementation period (c) different short (study at hand = 1 week) vs. long-term effects, (d) the possible (beneficial ?) involvement of mTOR, which has been shown to be activated by citrulline in previous trials (cf. SuppVersity Dec 28, 2011 and/or Le Plénier. 2011) (e) the fact that some athletes may benefit from the same shift towards glucose and the relative increase in type IIb fibers (not bodybuilders, though!) (f) ... I could go on with this list, but I guess you will see that there is no reason to panic.

    Take the Faure study as further evidence for our lack of understanding of the the complex effects and interplay of nutritional and supplemental amino acids on our health and don't forget to come back to the SuppVersity if you want to keep up with the "state of the art" ;-)

That's it for today! I hope you enjoyed the "ride" and stay tuned for future exercise, nutrition and health science potpourris - write-ups of which I believe they are a necessary and interesting intermediate between the mini-items on Facebook (don't forget to head over there and check out today's 9+ news items) and the elaborate "regular" SuppVersity articles.

  • Baralic I, Đorđević B, Đuričić I, Šobajić S, Stanković I, Dikić N (2013). Salivary IgA response to astaxanthin supplementation in young soccer players. Proceedings of the Nutrition Society, 72, E7.
  • Carlsohn A, Heydenreich J, Engel T, Kratzenstein S, Mayer F. Does immediate carbohydrate intake following glycogen-depleting exercise affect next day’s 5000 m time trial performance? International Journal of Sport Nutrition and Exercise Metabolism.  2013; 23(S1 -S15).
  • Duckworth LC, Backhouse SH, Stevenson EJ, O’Hara JP. Effect of galactose ingestion before and during exercise on substrate oxidation and subsequent energy intake in females. International Journal of Sport Nutrition and Exercise Metabolism.  2013; 23(S1 -S15).
  • Le Plénier, S., Walrand, S., Noirt, R., Cynober, L., Moinard, C., Effects of leucine and  citrulline versus non-essential amino acids on muscle protein synthesis in fasted rat: a common activation pathway? Amino Acids. 2011.
  • Krause MP, Liu Y, Vu V, Chan L, Xu A, Riddell MC, Sweeney G, Hawke TJ.Adiponectin is expressed by skeletal muscle fibers and influences muscle phenotype and function. Am J Physiol Cell Physiol. 2008 Jul;295(1):C203-12. 
  • Stuart CA, McCurry MP, Marino A, South MA, Howell ME, Layne AS, Ramsey MW, Stone MH. Slow-Twitch Fiber Proportion in Skeletal Muscle Correlates with Insulin. Responsiveness. J Clin Endocrinol Metab. 2013 Mar 20. 
  • Volkmann ER, Weekes NY. Basal SIgA and cortisol levels predict stress-related health outcomes. Stress and Health. 2006; 22: 11–23. 
  • Walsh NP, Gleeson M, Shephard RJ, Gleeson M, Woods JA, Bishop NC, Fleshner M, Green C, Pedersen BK, Hoffman-Goetz L, Rogers CJ, Northoff H, Abbasi A, Simon P. Position statement. Part one: Immune function and exercise. Exerc Immunol Rev. 2011;17:6-63. Review.