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The Carbohydrates SugarsStarchesFiber
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Carbohydrates (CH 2 O) n Simple carbohydratesSimple carbohydrates –Monosaccharides –Disaccharides Complex carbohydratesComplex carbohydrates
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Simple Carbohydrates MonosaccharidesMonosaccharides –C 6 H 12 O 6 Glucose (dextrose, blood sugar)Glucose (dextrose, blood sugar) FructoseFructose GalactoseGalactose
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Glucose
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Fructose & Galactose
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Condensation
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Hydrolysis
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Disaccharides Maltose = glucose + glucoseMaltose = glucose + glucose Sucrose = glucose + fructoseSucrose = glucose + fructose Lactose = glucose + galactoseLactose = glucose + galactose
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Complex Carbohydrates PolysaccharidesPolysaccharides –Glycogen (animal) –Starches (plant) –Fibers (non-starch polysaccharides)-not digested well.
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Glycogen & Starch Molecules Compared (small Segments)
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Complex Carbohydrates FibersFibers –Cellulose –Hemicelluloses –Pectins
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Complex Carbohydrates FibersFibers –Gums and mucilages –Lignin –Resistant starches
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Complex Carbohydrates FibersFibers –Soluble fibers Viscous-Gums, pectinsViscous-Gums, pectins FermentableFermentable
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Complex Carbohydrates FibersFibers –Insoluble fibers Nonviscous-cellulose, lignins, resistant starchesNonviscous-cellulose, lignins, resistant starches (Phytic acid)(Phytic acid)
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Digestion MouthMouth –Salivary amylase StomachStomach –Fibers and satiety
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Digestion Small intestineSmall intestine –Maltase, sucrase, lactase PancreasPancreas –Pancreatic amylase
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Carbohydrate Digestion in the GI Tract
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Digestion Large intestineLarge intestine –Fermentation of viscous fibers Water, gas, short-chain fatty acid productionWater, gas, short-chain fatty acid production
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Absorption
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Lactose Intolerance Symptoms-gas production, nausea, etc.Symptoms-gas production, nausea, etc. CausesCauses –Lactase deficiency
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Lactose Intolerance Prevalence-variablePrevalence-variable Dietary changesDietary changes –Does not require the elimination of milk/milk products –Acidophilus milk
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Glucose in the Body EnergyEnergy GlycoproteinsGlycoproteins GlycolipidsGlycolipids
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Carbohydrate Metabolism Storing glucose as glycogen (1/3)Storing glucose as glycogen (1/3) Using glucose for energyUsing glucose for energy
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Carbohydrate Metabolism Making glucose from proteinMaking glucose from protein –Gluconeogenesis –Protein-sparing action of carbohydrates
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Carbohydrate Metabolism Making ketone bodies from fat fragmentsMaking ketone bodies from fat fragments –Ketone bodies KetosisKetosis –Acid-base balance
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Carbohydrate Metabolism Converting glucose to fatConverting glucose to fat –Energetically expensive
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Constancy of Blood Glucose Regulating hormonesRegulating hormones –Insulin-uptake of sugar –Glucagon-release of sugar –Epinephrine-release (fight or flight)
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Maintaining Blood Glucose Homeostasis
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Constancy of Blood Glucose DiabetesDiabetes –Type 1 diabetes Failure of insulin productionFailure of insulin production –Type 2 diabetes-fat cells are insulin resistant! ObesityObesity
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Constancy of Blood Glucose HypoglycemiaHypoglycemia –Rare in healthy people
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Constancy of Blood Glucose Glycemic responseGlycemic response –Glycemic index
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Sugars Added sugarsAdded sugars –Sucrose, invert sugar, corn syrups, etc.
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Sugars Health effects of sugarsHealth effects of sugars –Nutrient deficiencies?
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Sugars Health effects of sugarsHealth effects of sugars –Dental caries Dental plaqueDental plaque
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Accusations Against Sugars Sugar causes obesity?Sugar causes obesity? Sugar causes heart disease?Sugar causes heart disease?
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Accusations Against Sugars Sugar causes misbehavior in children and criminal behavior in adults?Sugar causes misbehavior in children and criminal behavior in adults? Sugar causes cravings and addictions?Sugar causes cravings and addictions? –serotonin
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Recommended Intakes of Sugars DRIDRI –No more than 25% of total daily energy intake
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Carbs. Part II: Practical Aspects of Starches and Fibers
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Starch and Fiber Health effectsHealth effects –Heart disease –Diabetes –GI health
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Starch and Fiber Health effectsHealth effects –Cancer –Weight management –Harmful effects of excessive fiber intake
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Viscous Fibers
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Nonviscous Fibers
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Starch and Fiber RDA for carbohydrateRDA for carbohydrate –130 g/day –45% - 65% total daily energy intake Daily Value: 300 g/dayDaily Value: 300 g/day
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Starch and Fiber FiberFiber –Daily Value: 25 g/day –AI: 14 g/1000 kcal/day
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Guidelines to Groceries GrainsGrains
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Alternatives to Sugar Saccharine and cancerSaccharine and cancer Aspartame and PKUAspartame and PKU
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Artificial Sweeteners Also called nonnutritive sweetenersAlso called nonnutritive sweeteners –Saccharin Used primarily in soft drinks and as a tabletop sweetenerUsed primarily in soft drinks and as a tabletop sweetener Rapidly excreted in the urineRapidly excreted in the urine Does not accumulate in the bodyDoes not accumulate in the body Has been removed from list of cancer-causing substancesHas been removed from list of cancer-causing substances
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Artificial Sweeteners AspartameAspartame –General purpose sweetener –Warning about phenylalanine for those with PKU –Controversial finding that aspartame may have caused cancer in rats –Excessive intake should be avoided by those with epilepsy
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Artificial Sweeteners Acesulfame-K (acesulfame potassium)Acesulfame-K (acesulfame potassium) –Research confirms safety
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Artificial Sweeteners SucraloseSucralose –Made from sugar –Passes through digestive tract NeotameNeotame –Most recent on the market –Very sweet –Phenylalanine not an issue
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Artificial Sweeteners TagatoseTagatose –Used for foods and beverages –Provides less kcalories than sugar –High doses can cause flatulence and loose stools. Alitame and CyclamateAlitame and Cyclamate –Pending FDA approval –Approved in other countries
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Artificial Sweeteners Acceptable Daily Intake (ADI) is the level of consumption, maintained every day and still safe by a wide margin.Acceptable Daily Intake (ADI) is the level of consumption, maintained every day and still safe by a wide margin. –Moderation and variety are still recommended. Artificial Sweeteners and Weight ControlArtificial Sweeteners and Weight Control –Much research still being done –Using artificial sweeteners will not automatically reduce energy intake.
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Stevia – An Herbal Alternative Lacks researchLacks research Classified as a dietary supplementClassified as a dietary supplement Not required to have testing and FDA approvalNot required to have testing and FDA approval
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Sugar Replacers Also called nutritive sweeteners, sugar alcohols, and polyolsAlso called nutritive sweeteners, sugar alcohols, and polyols Maltitol, mannitol, sorbitol, xylitol, isomalt, and lactitolMaltitol, mannitol, sorbitol, xylitol, isomalt, and lactitol Absorbed more slowly and metabolized differently in the bodyAbsorbed more slowly and metabolized differently in the body Low glycemic responseLow glycemic response Side effects include GI discomfortSide effects include GI discomfort
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