Download - The Carbohydrates
The CarbohydratesThe Carbohydrates
SugarsSugars
StarchesStarches
FiberFiber
Carbohydrates (CHCarbohydrates (CH22O)O)nn
• Simple carbohydratesSimple carbohydrates– MonosaccharidesMonosaccharides– DisaccharidesDisaccharides
• Complex carbohydratesComplex carbohydrates
Simple CarbohydratesSimple Carbohydrates
• MonosaccharidesMonosaccharides
– CC66HH1212OO66
•Glucose (dextrose, blood sugar)Glucose (dextrose, blood sugar)•FructoseFructose•GalactoseGalactose
GlucoseGlucose
Fructose & GalactoseFructose & Galactose
CondensationCondensation
HydrolysisHydrolysis
DisaccharidesDisaccharides
• Maltose = glucose + glucoseMaltose = glucose + glucose
• Sucrose = glucose + fructoseSucrose = glucose + fructose
• Lactose = glucose + galactoseLactose = glucose + galactose
Complex CarbohydratesComplex Carbohydrates
• PolysaccharidesPolysaccharides– Glycogen (animal)Glycogen (animal)
– Starches (plant)Starches (plant)
– Fibers (non-starch polysaccharides)-not Fibers (non-starch polysaccharides)-not digested well.digested well.
Glycogen & Starch Molecules Compared Glycogen & Starch Molecules Compared (small Segments)(small Segments)
Complex CarbohydratesComplex Carbohydrates
• FibersFibers– CelluloseCellulose– HemicellulosesHemicelluloses– PectinsPectins
Complex CarbohydratesComplex Carbohydrates
• FibersFibers– Gums and mucilagesGums and mucilages– LigninLignin– Resistant starchesResistant starches
Complex CarbohydratesComplex Carbohydrates
• FibersFibers– Soluble fibersSoluble fibers
•Viscous-Gums, pectinsViscous-Gums, pectins•FermentableFermentable
Complex CarbohydratesComplex Carbohydrates
• FibersFibers– Insoluble fibersInsoluble fibers
•Nonviscous-cellulose, lignins, Nonviscous-cellulose, lignins, resistant starchesresistant starches
• (Phytic acid)(Phytic acid)
DigestionDigestion
• MouthMouth– Salivary amylaseSalivary amylase
• StomachStomach– Fibers and satietyFibers and satiety
DigestionDigestion
• Small intestineSmall intestine– Maltase, sucrase, lactaseMaltase, sucrase, lactase
• PancreasPancreas– Pancreatic amylasePancreatic amylase
Carbohydrate Carbohydrate Digestion in the Digestion in the
GI TractGI Tract
DigestionDigestion
• Large intestineLarge intestine– Fermentation of viscous fibersFermentation of viscous fibers
•Water, gas, short-chain fatty Water, gas, short-chain fatty acid productionacid production
AbsorptionAbsorption
Lactose IntoleranceLactose Intolerance
• Symptoms-gas production, nausea, Symptoms-gas production, nausea, etc.etc.
• CausesCauses– Lactase deficiencyLactase deficiency
Lactose IntoleranceLactose Intolerance
• Prevalence-variablePrevalence-variable
• Dietary changesDietary changes– Does not require the elimination Does not require the elimination
of milk/milk productsof milk/milk products– AcidophilusAcidophilus milk milk
Glucose in the BodyGlucose in the Body
• EnergyEnergy
• GlycoproteinsGlycoproteins
• GlycolipidsGlycolipids
Carbohydrate MetabolismCarbohydrate Metabolism
• Storing Storing glucose as glucose as glycogen (1/3)glycogen (1/3)
• Using glucose Using glucose for energyfor energy
Carbohydrate MetabolismCarbohydrate Metabolism
• Making glucose from proteinMaking glucose from protein– GluconeogenesisGluconeogenesis
– Protein-sparing action of Protein-sparing action of carbohydratescarbohydrates
Carbohydrate MetabolismCarbohydrate Metabolism
• Making ketone bodies from fat Making ketone bodies from fat fragmentsfragments– Ketone bodiesKetone bodies
•KetosisKetosis–Acid-base balanceAcid-base balance
Carbohydrate MetabolismCarbohydrate Metabolism
• Converting glucose to fatConverting glucose to fat– Energetically expensiveEnergetically expensive
Constancy of Blood Constancy of Blood GlucoseGlucose
• Regulating hormonesRegulating hormones– Insulin-uptake of sugarInsulin-uptake of sugar– Glucagon-release of sugarGlucagon-release of sugar– Epinephrine-release (fight or Epinephrine-release (fight or
flight)flight)
Maintaining Blood Maintaining Blood Glucose HomeostasisGlucose Homeostasis
Constancy of Blood Constancy of Blood GlucoseGlucose
• DiabetesDiabetes– Type 1 diabetesType 1 diabetes
•Failure of insulin productionFailure of insulin production– Type 2 diabetes-fat cells are Type 2 diabetes-fat cells are
insulin resistant!insulin resistant!•ObesityObesity
Constancy of Blood Constancy of Blood GlucoseGlucose
• HypoglycemiaHypoglycemia– Rare in healthy peopleRare in healthy people
Constancy of Blood Constancy of Blood GlucoseGlucose
• Glycemic responseGlycemic response– Glycemic indexGlycemic index
SugarsSugars
• Added sugarsAdded sugars– Sucrose, invert sugar, corn Sucrose, invert sugar, corn
syrups, etc.syrups, etc.
SugarsSugars
• Health effects Health effects of sugarsof sugars– Nutrient Nutrient
deficiencies?deficiencies?
SugarsSugars
• Health effects of Health effects of sugarssugars– Dental cariesDental caries
•Dental plaqueDental plaque
Accusations Accusations Against SugarsAgainst Sugars
• Sugar causes Sugar causes obesity?obesity?
• Sugar causes Sugar causes heart disease?heart disease?
Accusations Accusations Against SugarsAgainst Sugars
• Sugar causes misbehavior in Sugar causes misbehavior in children and criminal behavior in children and criminal behavior in adults? adults?
• Sugar causes cravings and Sugar causes cravings and addictions?addictions?– serotoninserotonin
Recommended Intakes of Recommended Intakes of SugarsSugars
• DRIDRI– No more than 25% of total daily No more than 25% of total daily
energy intake energy intake
Carbs. Part II: Practical Aspects of Carbs. Part II: Practical Aspects of Starches and FibersStarches and Fibers
Starch and FiberStarch and Fiber
• Health effectsHealth effects– Heart diseaseHeart disease– DiabetesDiabetes– GI healthGI health
Starch and FiberStarch and Fiber
• Health effectsHealth effects– CancerCancer– Weight managementWeight management– Harmful effects of excessive fiber Harmful effects of excessive fiber
intakeintake
Viscous FibersViscous Fibers
Nonviscous FibersNonviscous Fibers
Starch and FiberStarch and Fiber
• RDA for carbohydrateRDA for carbohydrate– 130 g/day130 g/day– 45% - 65% total daily energy 45% - 65% total daily energy
intakeintake
• Daily Value: 300 g/dayDaily Value: 300 g/day
Starch and FiberStarch and Fiber
• FiberFiber– Daily Value: 25 g/dayDaily Value: 25 g/day– AI: 14 g/1000 kcal/dayAI: 14 g/1000 kcal/day
Guidelines Guidelines to Groceriesto Groceries
• GrainsGrains
Alternatives to SugarAlternatives to Sugar
• Saccharine and cancerSaccharine and cancer• Aspartame and PKUAspartame and PKU
Artificial SweetenersArtificial Sweeteners
• Also called nonnutritive sweetenersAlso called nonnutritive sweeteners– SaccharinSaccharin
• Used primarily in soft drinks and as a tabletop Used primarily in soft drinks and as a tabletop sweetenersweetener
• 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 Has been removed from list of cancer-causing substancessubstances
Artificial SweetenersArtificial Sweeteners
• AspartameAspartame– General purpose sweetenerGeneral purpose sweetener– Warning about phenylalanine for those with Warning about phenylalanine for those with
PKUPKU– Controversial finding that aspartame may have Controversial finding that aspartame may have
caused cancer in ratscaused cancer in rats– Excessive intake should be avoided by those Excessive intake should be avoided by those
with epilepsywith epilepsy
Artificial SweetenersArtificial Sweeteners
• Acesulfame-K (acesulfame potassium)Acesulfame-K (acesulfame potassium)– Research confirms safetyResearch confirms safety
Artificial SweetenersArtificial Sweeteners
• SucraloseSucralose– Made from sugarMade from sugar– Passes through digestive tractPasses through digestive tract
• NeotameNeotame– Most recent on the marketMost recent on the market– Very sweetVery sweet– Phenylalanine not an issuePhenylalanine not an issue
Artificial SweetenersArtificial Sweeteners
• TagatoseTagatose– Used for foods and beveragesUsed for foods and beverages– Provides less kcalories than sugarProvides less kcalories than sugar– High doses can cause flatulence and loose High doses can cause flatulence and loose
stools.stools.
• Alitame and CyclamateAlitame and Cyclamate– Pending FDA approvalPending FDA approval– Approved in other countriesApproved in other countries
Artificial SweetenersArtificial Sweeteners
• Acceptable Daily Intake (ADI) is the level of Acceptable Daily Intake (ADI) is the level of consumption, maintained every day and still safe consumption, maintained every day and still safe by a wide margin. by a wide margin. – Moderation and variety are still recommended.Moderation and variety are still recommended.
• Artificial Sweeteners and Weight ControlArtificial Sweeteners and Weight Control– Much research still being doneMuch research still being done
– Using artificial sweeteners will not automatically Using artificial sweeteners will not automatically reduce energy intake.reduce energy intake.
Stevia – An Herbal AlternativeStevia – An Herbal Alternative
• Lacks researchLacks research
• Classified as a dietary supplementClassified as a dietary supplement
• Not required to have testing and FDA Not required to have testing and FDA approvalapproval
Sugar ReplacersSugar Replacers
• Also called nutritive sweeteners, sugar Also called nutritive sweeteners, sugar alcohols, and polyolsalcohols, and polyols
• Maltitol, mannitol, sorbitol, xylitol, isomalt, Maltitol, mannitol, sorbitol, xylitol, isomalt, and lactitoland lactitol
• Absorbed more slowly and metabolized Absorbed more slowly and metabolized differently in the bodydifferently in the body
• Low glycemic responseLow glycemic response
• Side effects include GI discomfortSide effects include GI discomfort