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)


• FibersFibers– CelluloseCellulose– HemicellulosesHemicelluloses– PectinsPectins


• FibersFibers– Gums and mucilagesGums and mucilages– LigninLignin– Resistant starchesResistant starches


• FibersFibers– Soluble fibersSoluble fibers

•Viscous-Gums, pectinsViscous-Gums, pectins•FermentableFermentable


• 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


• Making glucose from proteinMaking glucose from protein– GluconeogenesisGluconeogenesis

– Protein-sparing action of Protein-sparing action of carbohydratescarbohydrates


• Making ketone bodies from fat Making ketone bodies from fat fragmentsfragments– Ketone bodiesKetone bodies

•KetosisKetosis–Acid-base balanceAcid-base balance


• 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


• 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


• HypoglycemiaHypoglycemia– Rare in healthy peopleRare in healthy people


• 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


• Health effectsHealth effects– CancerCancer– Weight managementWeight management– Harmful effects of excessive fiber Harmful effects of excessive fiber

intakeintake

Viscous FibersViscous Fibers

Nonviscous FibersNonviscous Fibers


• 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


• 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


• 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


• Acesulfame-K (acesulfame potassium)Acesulfame-K (acesulfame potassium)– Research confirms safetyResearch confirms safety


• 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


• 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


• 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

Documents

The Carbohydrates