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The Science of Energy Gels

Revision as of 16:12, 12 April 2013 by User:Fellrnr (User talk:Fellrnr | contribs)

Revision as of 16:12, 12 April 2013 by User:Fellrnr (User talk:Fellrnr | contribs)

My supply of gels
Understanding some of the science behind energy gels can help in evaluating and choosing the right gel.

Contents

1 Carbohydrate Absorption

There are three main components to the ease of absorption of a carbohydrate; how much water needs to be used to dilute it, how fast it gets into the blood and the digestive path in the gut.

1.1 Required Dilution – Isotonic Drinks

Isotonic drinks have a similar concentration (osmolality) of carbohydrate and electrolytes to the human blood and are easier to absorb[1]. The concentration is based on the number of molecules rather than the weight, so an isotonic drink with bigger molecules has more carbohydrate by weight. Maltodextrin is a long molecule that is a chain of glucose, so you can have a lot of it in an isotonic solution. Maltodextrin is isotonic at 150g/500ml, where fructose, glucose and sucrose (table sugar) are isotonic at 26g/500ml. This means that you need to dilute the simple sugars with six times as much water as Maltodextrin.

1.2 Absorption Rate - Glycemic Index

Main article: Glycemic Index

Glycemic index reflects how high a carbohydrate raises the blood sugar level.

  • Glucose is the standard against which everything else is measured, so it has a Glycemic Index of 100. Glucose is used because it raises the blood sugar faster than almost anything else.
  • Maltodextrin actually has a glycemic index of over 100, with values between 105 and 136.
  • Fructose has a low glycemic index of 19, as it has to go via the liver to be converted to glucose.

1.3 Digestive Path

While fructose has a low isotonic concentration and a low glycemic index, it can be absorbed via a different path (GLUT5) to glucose and Maltodextrin (GLUT2). This means that if you have enough glucose or Maltodextrin to saturate that absorption path, adding fructose will improve the overall usage of the carbohydrate intake[2].

1.4 Optimal Carbohydrate Intake

Most studies have shown that glucose and Maltodextrin can be absorbed and metabolized at up to 1.0 grams/minute, while Fructose is absorbed and metabolized at up to 0.6 grams/minute[3]. Combining Fructose with glucose/Maltodextrin can result in the metabolism of up to 1.75 grams/minuteCite error: Closing </ref> missing for <ref> tag [4][5][6][7][8][9][2][1][10][11][3][12][13][14][15][16][17][18]

</references>
  1. ↑ 1.0 1.1 http://jap.physiology.org/cgi/content/full/85/5/1941 Hypertonic solutions are less easily absorbed
  2. ↑ 2.0 2.1 DS. Rowlands, MS. Thorburn, RM. Thorp, S. Broadbent, X. Shi, Effect of graded fructose coingestion with maltodextrin on exogenous 14C-fructose and 13C-glucose oxidation efficiency and high-intensity cycling performance., J Appl Physiol, volume 104, issue 6, pages 1709-19, Jun 2008, doi 10.1152/japplphysiol.00878.2007, PMID 18369092
  3. ↑ 3.0 3.1 Asker E Jeukendrup, Carbohydrate intake during exercise and performance, Nutrition, volume 20, issue 7-8, 2004, pages 669–677, ISSN 08999007, doi 10.1016/j.nut.2004.04.017
  4. ↑ AE. Jeukendrup, SC. Killer, The myths surrounding pre-exercise carbohydrate feeding., Ann Nutr Metab, volume 57 Suppl 2, pages 18-25, 2010, doi 10.1159/000322698, PMID 21346333
  5. ↑ J.F. Brun, C. Fedou, J. Mercier, "Postprandial Reactive Hypoglycemia," Diabetes & Metabolism (Paris) 2000, 26, 337-351
  6. ↑ F. Brouns, NJ. Rehrer, WH. Saris, E. Beckers, P. Menheere, F. ten Hoor, Effect of carbohydrate intake during warming-up on the regulation of blood glucose during exercise., Int J Sports Med, volume 10 Suppl 1, pages S68-75, May 1989, doi 10.1055/s-2007-1024956, PMID 2663744
  7. ↑ H. Kuipers, EJ. Fransen, HA. Keizer, Pre-exercise ingestion of carbohydrate and transient hypoglycemia during exercise., Int J Sports Med, volume 20, issue 4, pages 227-31, May 1999, doi 10.1055/s-2007-971122, PMID 10376478
  8. ↑ http://www.arniebakercycling.com/pubs/Free/Nutrition%20Maltodextrin%20SS.pdf
  9. ↑ G M Gray, Intestinal Digestion and Maldigestion of Dietary Carbohydrates, Annual Review of Medicine, volume 22, issue 1, 1971, pages 391–404, ISSN 0066-4219, doi 10.1146/annurev.me.22.020171.002135
  10. ↑ Brian P. Jackson, Vivien F. Taylor, Margaret R. Karagas, Tracy Punshon, Kathryn L. Cottingham, Arsenic, Organic Foods, and Brown Rice Syrup, Environmental Health Perspectives, volume 120, issue 5, 2012, pages 623–626, ISSN 0091-6765, doi 10.1289/ehp.1104619
  11. ↑ Sweetness http://biology.clc.uc.edu/courses/bio104/carbohydrates.htm
  12. ↑ Asker E Jeukendrup, Carbohydrate and exercise performance: the role of multiple transportable carbohydrates, Current Opinion in Clinical Nutrition and Metabolic Care, volume 13, issue 4, 2010, pages 452–457, ISSN 1363-1950, doi 10.1097/MCO.0b013e328339de9f
  13. ↑ R. Van Thienen, K. Van Proeyen, B. Vanden Eynde, J. Puype, T. Lefere, P. Hespel, Beta-alanine improves sprint performance in endurance cycling., Med Sci Sports Exerc, volume 41, issue 4, pages 898-903, Apr 2009, doi 10.1249/MSS.0b013e31818db708, PMID 19276843
  14. ↑ JR. Hoffman, NA. Ratamess, AD. Faigenbaum, R. Ross, J. Kang, JR. Stout, JA. Wise, Short-duration beta-alanine supplementation increases training volume and reduces subjective feelings of fatigue in college football players., Nutr Res, volume 28, issue 1, pages 31-5, Jan 2008, doi 10.1016/j.nutres.2007.11.004, PMID 19083385
  15. ↑ GG. Artioli, B. Gualano, A. Smith, J. Stout, AH. Lancha, Role of beta-alanine supplementation on muscle carnosine and exercise performance., Med Sci Sports Exerc, volume 42, issue 6, pages 1162-73, Jun 2010, doi 10.1249/MSS.0b013e3181c74e38, PMID 20479615
  16. ↑ A. Baguet, K. Koppo, A. Pottier, W. Derave, Beta-alanine supplementation reduces acidosis but not oxygen uptake response during high-intensity cycling exercise., Eur J Appl Physiol, volume 108, issue 3, pages 495-503, Feb 2010, doi 10.1007/s00421-009-1225-0, PMID 19841932
  17. ↑ KM. Sweeney, GA. Wright, A. Glenn Brice, ST. Doberstein, The effect of beta-alanine supplementation on power performance during repeated sprint activity., J Strength Cond Res, volume 24, issue 1, pages 79-87, Jan 2010, doi 10.1519/JSC.0b013e3181c63bd5, PMID 19935102
  18. ↑ W. Derave, MS. Ozdemir, RC. Harris, A. Pottier, H. Reyngoudt, K. Koppo, JA. Wise, E. Achten, beta-Alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters., J Appl Physiol, volume 103, issue 5, pages 1736-43, Nov 2007, doi 10.1152/japplphysiol.00397.2007, PMID 17690198
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Last edited on 12 April 2013, at 16:13