Carbohydrates What are Carbohydrates CHO make up 3

Carbohydrates

What are Carbohydrates? • CHO make up 3% of the body’s organic matter • CHO are compounds constructed in a ratio of one atom of carbon and two atoms of hydrogen for each oxygen atom • Chemical Formula = (CH 2 O)n – Where n is from 3 to 7 carbon atoms – 5 carbon sugars are called pentoses – 6 carbon sugars are called hexoses (most common)

Carbohydrate 2 Hydrogen for each Oxygen

Glucose - C 6 H 12 O 6

Categories of Carbohydrates • Monosaccharides (glucose, fructose, galactose • Disaccharides (sucrose, maltose, lactose) • Polysaccharides (starch, fiber, glycogen)

Monosaccharides • Glucose • Fructose • Galactose

Dissaccarides • Combination of 2 or more monosaccharides – Mono + Disaccharides = SIMPLE SUGARS Sucrose = glucose + fructose (brown sugar; 25% of sugar intake) Lactose = glucose + galactose (milk sugar; least sweet) Maltose = glucose + glucose (honey) Natural Sweetness

Is Refined Sugar a Villain? • To much sugar results in eating less of something else - Sugar Causes Malnutrition • Eating sugar without eating less of something else, results in enough nutrients but too many k. Cal - Sugar Causes Obesity • Excess sugar converts to fat and so causes hyperlipidemia - Sugar Causes High Levels of Blood fat and Atherosclerosis • Concentrated sugar is not natural and dangerous • Sugar causes diabetes • Sugar causes tooth decay

Polysaccharides 3 or more simple sugars combined Plant Polysaccharides Starch peas, seeds, corn, gains, cereals, potatoes, roots Cellulose fiber (technically not a nutrient)

Polysaccharides • Animal Polysaccharides - GLYCOGEN – Ranges in size from a few hundred to thousands of glucose molecules linked together like sausage links – 375 -475 g stored in body (liver, muscle, kidney) – Can be modified by diet and exercise

Animal Polysaccharides • Glycogen – Large molecules – Stored in liver (100 g) and muscle (325 g) – Because little glycogen is stored - it can be modified by diet and exercise – Why do we want to conserve muscle glycogen? • Glucose intake during exercise 70 g/140 H 2 O, 20 -30 min prior to exercise

CHO Conversions • GLYCOGENESIS = Glycogen derived from glucose • Glycogenolysis = In liver, glucose derived from glycogen • Gluconeogenesis = In liver, glucose derived from protein (non CHO products)

Dietary Fiber • Water insoluble fibers [cellulose, hemicellulose, lignins, pectins, gums, wheat bran] • Water soluble fiber [oats, beans, rice, peas, carrots, fruits] • Health Implications of Fiber [obesity, diabetes, intestinal disorders, cancer, cholesterol effects] • Recommended intake of fiber [ 20 -30 g/d] – Americans eat about 12 g/d – Africans eat about 40 -150 g/d Guess who has the highest incidence of colorectal cancer?

Not All CHO The Same The Glycemic Index GI = a relative measure of the extent to which blood glucose increases after ingesting 50 g of CHO.

Functions of CHO • Energy Source • Protein Sparing • Metabolic Primer • CNS Fuel

Sources of CHO

What Happens when you Consume CHO? Blood Glucose Liver Glycogen Muscle Glycogen Adipose Tissue Kidney Excretion Used for Energy [Type, duration, intensity]

Hypoglycemia v Hyperglycemia Hypoglycemia - low blood sugar; hormones (glucagon) stimulate liver to release sugar into blood Hyperglycemia - high blood sugar; insulin aids sugar uptake from blood to cells; with excess blood sugar, spills out to kidneys and is urinated out (sweet urine). Sensitivity v underproduction

CHO and Endurance Exercise