CARBOHYDRATES Types Sources Absorption Related to Exercise Lecture
CARBOHYDRATES: Types, Sources & Absorption Related to Exercise Lecture content provided by GSSI, a division of Pepsi. Co, Inc. Any opinions or scientific interpretations expressed in this presentation are those of the author and do not necessarily reflect the position or policy of Pepsi. Co, Inc.
Carbohydrates are the primary fuel for muscle contraction
CONSUMING CARBOHYDRATES WILL … Maintain high rates of carbohydrate oxidation Reduce ratings of perceived exertion Increase endurance capacity Delay the onset of fatigue Prevent hypoglycemia Cermak & van Loon. Sports Med. 2013; 43: 1139 -1155 Jeukendrup A. Nutrition. 2004; 20: 669 -677
MECHANISM Glycogen sparing Glycogen re-synthesis High rate of CHO Ox Phillips et. al. Sports Med. 2011; 41: 559 -585 Baker L et. al. Nutrients. 2015; 7: 5733 -5763 Jeukendrup, Rollo, Carter. Sports Science Exchange. (2013; 26(118): 1 -8
CARBOHYDRATES AND TEAM SPORTS Field Sports STRENGTH + POWER ENDURANCE Short distances covered, many short bursts Large distances covered, high speeds Batting Sports Court Sports Lower overall energy demands, long duration Smaller area, shorter duration, tournaments, substitutions CARBOHYDRATES ARE ESSENTIAL Maintain short energy bursts To maintain glycogen stores To maintain blood glucose for attention & decision making To maintain glycogen over time Holway & Spriet. J Sport Sci. 2011; 29(1): S 115 -125
CARBOHYDRATE Defined An organic compound made of carbon, hydrogen, & oxygen A class of food that is rich in sugars, starches, or fibers An individual carbohydrate is classified as a sugar, starch, or fiber depending on the structure and number of glucose molecules
CARBOHYDRATE Classifications monosaccharide disaccharide n polysaccharide/ glucose polymer Simple Carbohydrates (Sugars) Complex Carbohydrates (Starches/Fibers)
Monosaccharides glucose fructose galactose
Disaccharides Sucrose Lactose Maltose
Polysaccharides amylose amylopectin
Maltodextrin ü ü Group of glucose polymers Produced from potato or corn starch Same oxidation rate as glucose and sucrose Common carbohydrate source in sports nutrition products
Mono Di Glucose Sucrose Fructose Lactose Poly Starch • Amylose • Amylopectin Fiber Galactose Maltose • Soluble • Insoluble
Mono Di Poly
CARBOHYDRATE Classification Carbohydrates are often classified as “simple” and complex” based on their structures But, this chemical classification doesn’t reflect the physiology of the carbohydrate in the body Rather than simple/complex, choice of carbohydrate for athletes during exercise should be based on oxidation rate SSE #106 Jeukendrup A. Sports Science Exchange. 2007; 20(106)1 -6
Carbohydrate Structure Classifications SIMPLE COMPLEX Glucose Amylose Fructose Amylopectin Galactose Sucrose Maltose
Types of Carbohydrates FASTER SLOWER Glucose Maltose Fructose Rapid Digestion Galactose Slow Digestion Sucrose Trehalose Maltodextrins Isomalatulose Amylopectin 1. 0 g/min (60 g/h) Amylose . 06 g/min (35 g/h) Jeukendrup A. Sports Science Exchange. 2007; 20(3)1 -6
During exercise, think about carbs as… FAST & SLOW
120 min @ 65% max 60 min rest 30 min @ 60% max Exogenous CHO oxidation (g/min) Example: Oxidation Rates during Cycling 0. 9 * 0. 8 0. 7 0. 6 0. 5 46% oxidized 0. 4 8% 13 C-enriched glucose –or- galactose 0. 3 8 m. L/kg pre 2 m. L/kg every 15 min 0. 1 21% oxidized 0. 2 0 Glucose Galactose Leijssen et. al. JAP. 1985; 79: 720 -725
Fructose + glucose combination (You don’t need all “fast” sugars) FRUCTOSE + GLUCOSE 3. 05 3. 15 3. 2 Total CHO Oxidation (g/min) 3. 25 3. 35 Lecoultre et. al. AJCN. 2010; 92: 1071 -1079
A faster rate of carbon oxidation can result in a better performance Jeukendrup A. Sports Science Exchange. 2013; 26(108): 1 -5 Jeukendrup A. Curr Opin Clin Nutr Metab Care. 2010; 13: 452 -457
Lumen SGLT 1 H 2 O GLUT 5 H 2 O (galactose) fructose glucose 2 Na+ H 2 O ATP fructose glucose fructose H 2 O (passive diffusion) Na+ H 2 O, Na+, K+, Cl- Na+ GLUT 2 glucose, galactose, fructose H 2 O AQP glucose, galactose, fructose Solvent drag K+ Paracellular transport glucose (galactose) K+ ? ? ? DRTS sucrose H 2 O H 2 O, Na+, K+, Cl- Plasma
Welcome To Circulation Sugar International Toll Plaza Glucose Only Pay Toll Fructose Only Pay Toll Now Leaving Intestinal Lumen
Welcome To Circulation Sugar International Toll Plaza Pa To y ll Glucose Only Pay Toll Fructose Only Pay Toll Now Leaving Intestinal Lumen
Welcome To Circulation Sugar International Toll Plaza Glucose Only Pay Toll Fructose Only Pay Toll Now Leaving Intestinal Lumen
Welcome To Circulation Sugar International Toll Plaza Fructose Only Pa To y ll Glucose Only Now Leaving Intestinal Lumen
Common Sugars in Sports Nutrition Products Dietary Sugar Source After digestion: Glucose Sucrose 46% Glucose + Fructose oxidized Maltodextrin Glucose High Fructose Corn Syrup 21% Glucose + Fructose Organic Cane Sugar, Honey, Molasses, Agave nectar, Fruit juice concentrate Glucose + Fructose oxidized
Multiple Transportable Carbohydrates SSE #108 Endurance activities > 2. 5 hours Aim for 90 g/h, use multiple transporters The CHO source should be a mix of glucose and fructose, or maltodextrin and fructose in a ratio of roughly 2: 1, so there is 60 g/h of glucose or maltodextrin (to saturate the SGLT 1 transporters) and 30 g/h of additional fructose for oxidation. 65% Higher exogenous CHO oxidation Jeukendrup A. Sports Science Exchange. 2013; 26(108): 1 -5
Sugar Gets a Bad Rap Sugar is often demonized, labeled as being “toxic” Many quickly oxidized carbohydrates are sugars For athletes, it’s important to differentiate the need for a functional CHO (sugar) during exercise due to fast absorption and oxidation – it won’t provide energy if it’s sitting in the gut causing GI upset!
All-Day Carbohydrate Intake • For sports nutrition needs (pre/during/post exercise) the focus should be on quickly oxidized CHO • Throughout the rest of the day, athletes should focus on nutrient-rich sources regardless of oxidation rate, including fruits, vegetables, whole grains and legumes • 25 -30 g/d = recommended fiber intake from food
ZERO CALORIE S (artificial sweeteners) ZERO ENERGY
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