Lect3.CHO - Carbohydrates Six Categories of Nutrients Six...

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Unformatted text preview: Carbohydrates Six Categories of Nutrients Six • Carbohydrates • Lipids (fats) • Proteins • Vitamins • Minerals • Water Nutrient Use Nutrient Biological Work • Maintenance/repair • Cellular regulation • Energy source • Nerves • New tissue Besides carbon (C), most nutrients contain oxygen + (O2) and hydrogen (H ) (O • The organization of of these 3 atoms and their specific proportions determine whether the compound in a CHO, Lipid or Protein • All nutrients except water and minerals contain Carbon. Some contain few carbon atoms, some hundreds or even thousands of carbon atoms. Chemical Differences Between Nutrients Between C C =C What are Carbohydrates? What • CHO make up 3% of the body’s organic matter • CHO are compounds constructed in a ratio of 1 atom of carbon and 2 atoms of hydrogen for each oxygen O)n atom Chemical Formula = (CH Carbohydrate Carbohydrate 2 Hydrogen for each Oxygen C6H12O6 [Glucose] Glucose - C6H12O6 A Sugar is a Sugar is a…. Sugar •Glucose •Dextrose •Fructorse •Lactose •Maltose •Sucrose • Granulated sugar • Confectioner’ sugar • Brown sugar • Corn syrup • Honey •Invert sugar •Maple syrup •Molasses •Mannitol •Sorbitol •Sorghum Categories of Carbohydrates Categories • Monosaccharides (glucose, fructose, galactose) • Disaccharides (sucrose, maltose, lactose) • Polysaccharides (starch, fiber, glycogen) •Single sugar units •Glucose Monosaccharides Monosaccharides •Found in fruits, vegetables, honey •“blood sugar” – used for energy •Fructose •Found in fruits, honey, corn syrup •“fruit sugar” •Galactose •Found as part of lactose in milk • Combination of 2 or more monosaccharides Dissaccarides Mono + Disaccharides = SIMPLE SUGARS Mono SIMPLE Sucrose = glucose + fructose (brown sugar; 25% of sugar intake) Lactose = glucose + galactose (milk sugar; least sweet) Maltose = glucose + glucose (honey) Natural Sweetness CHO Digestion and Absorption Absorption • Mouth – Salivary amylase begins digestion of starch • Small intestine – Pancreatic amylase completes starch digestion – Brush border enzymes digest disaccharides • End products of carbohydrate digestion – Glucose, fructose, galactose – Absorbed into bloodstream • Fibers are not digested, are excreted in feces Simple Sugars Stimulates Insulin Production Insulin • Repeated intake of simple sugar stimulates insulin production (to remove CHO from blood). –Why is this bad? CHO in the Body CHO • Body tries to maintain a constant blood level of CHO by modulating storage and production What Happens when you Consume CHO? Consume Blood Glucose Liver Glycogen Muscle Glycogen Adipose Tissue Kidney Excretion Used for Energy [Type, duration, intensity] CHO Conversions CHO • Glycogenesis = Glycogen derived from glucose • Glycogenolysis = Glucose derived from glycogen in liver • Gluconeogenesis = Glucose derived from protein (non CHO products) in liver Hypoglycemia v Hyperglycemia Hypoglycemia Hypoglycemia glucagon stimulates liver to release sugar to blood Hyperglycemia 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 Is Refined Sugar a Villain? Is • To much sugar results in eating less of To something else - Sugar Causes Malnutrition Malnutrition • Eating sugar without eating less of Eating something else, results in enough nutrients but too many kCal - Sugar Causes Obesity Obesity • Excess sugar converts to fat and so causes Excess hyperlipidemia and atherosclerosis hyperlipidemia • Sugar causes diabetes • Sugar causes tooth decay Sugars and Diabetes Sugars Diabetes • What is Diabetes? • What is Insulin? • What Happens in Type 2? • What Happens in Type 1? Diabetes What is Diabetes http://diabetes.emedtv.com/diabetes-video/diabetes----what-is-it-video.ht Types of Diabetes http://diabetes.emedtv.com/diabetes-video/diabetes----what-is-it-video.ht Blood Glucose Regulation Diabetes Symptoms Excessive Thirst – Glucose levels rise so high so kidneys excrete glucose, drawing fluid with it and increasing urine volume Blurred Vision – excess glucose enters the lens of the eye causing swelling Weight Loss – glucose cannot be used for energy so body breaks down fat and protein to supply fuel. Use of protein causes release of ketones that causes increase in blood acidity Simple Sugar and Health Dental Caries – sugar on the teeth Hyperactivity – no clear evidence, but suggestive Body Weight/Fat Increase – does – response Heart Disease – increase in blood lipids Diabetes – Chronic Bowel Disorders – lack of fiber related Colon Cancer – lack of fiber related Sugar as Additives Sugar • We consume about 158 lbs of sweeteners/ per person/yr – Sucrose, fructose, high-fructose corn syrup, corn Sucrose, syrup, maltose, honey, molasses syrup, – Used to color foods – darkens with heated – Used to preserve foods in jams and jellies (sugar Used hold water and prevent microorgainism growth hold Polysaccharides Polysaccharides (3 or more simple sugars combined) Plant Polysaccharides Starch peas, seeds, corn, gains, cereals, potatoes, roots Cellulose fiber (technically not a nutrient) What Kind of Bread to eat? What Polysaccharides Polysaccharides Animal Polysaccharides GLYCOGEN • Ranges in size from a few hundred to thousands of glucose molecules linked together like sausage links • 375-500 g stored in body (liver, muscle, kidney) • Can be modified by diet and exercise Sugar as Sweeteners Sugar • We consume 20.5 teaspoons/day – Saccharin – (1977) 200-700 more sweet than sugar; Saccharin causes bladder disease in rodents; non caloric causes – Aspartame – (1983) 200 times sweeter; made of 2 AA Aspartame breaks down when heated so works best when nonbreaks cooked (NutraSweet, Equal, (NrutriTaste); 4 kCal/g – Acesulfame K – (1988) (Sunette) 200 times as sweet; Acesulfame non kcal; ok in baking non – Sucralose – only non-kcal sweetener made from Sucralose sugar; 600 times as sweet; (Splenda); so far safe sugar; – Sugar Alcohols – (sorbitol, mannitol, lactitol, Xylitol); Sugar non digested same as sugar, less kcal; cause diarrhea non Dietary Fiber Dietary [high grade fiber: whole grain bread, cereals, fruits, veggies (figs, skins, stalks, [high seeds)] seeds)] • 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 Dietary Fiber Dietary • Recommended intake of fiber [20-35 g/day; insoluble:soluble = 3:1] – Americans eat about 12 g/d – Africans eat about 40-150 g/d Guess who has the highest incidence of colorectal cancer? What Causes Hemorrhoids? What [1 of 4 students inflicted] • Consuming too much fiber can produce overly mushy stool (stool = undigested fragments of plant fiber, connective tissue, from animal foods, bacteria and water • Consuming too little fiber can cause the stool to become hard and difficult to pass • While straining to rid the stool, blood vessels in the rectal area become exposed and bleed. Surgery may be required to correct the condition Function of CHO Function • Energy Source • Protein Sparing • Metabolic Primer • CNS Fuel • Glycogen Storage (muscle, liver) (muscle, Glycogen • • • • Sources of CHO Sources Dairy Fruits Cereals Meats –Complex v Simple Sugars The average college student will consume The 165 lbs of simple sugar per year and 10 lbs 165 10 of non CHO chemical sweeteners! of CHO In The Diet CHO in the Diet • Nutritive Sweeteners – Natural v. refined – Sugar alcohols • Artificial Sweeteners – Saccharin – Aspartame – Acesulfame K – Sucralose Is There a Recommended Intake for CHO? Intake Can You Become Fat by Consuming Too Much CHO? Consuming The answer should The be obvious be Fatness and CHO Fatness • Once blood and cells becomes fully packed with glycogen (so it can’t hold any more), CHO converts to CHO Fat and stored as triglyceride in Fat the body’s fat (adipose tissues) stores • How long does this process take? Not All CHO The Same Not GI = a relative measure of the extent to which blood glucose increases after ingesting 50 g of CHO The Glycemic Index Implications for GI Values Implications • Exercise • Recovery –Consume 50-75 g (2-3 oz)of high to moderate GI foods every 2 h after exercise, or eat high glycemic meal CHO and Exercise CHO • Intense exercise • Moderate exercise • Endurance exercise CHO and Endurance Exercise CHO ...
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