1.  The first food component that we will beThe first food component that we will be
discussing is carbohydrates!!!discussing is carbohydrates!!!

2. CarbohydratesCarbohydrates

3. CarbohydratesCarbohydrates
 carbohydratecarbohydrate (pronounced /k rbɑ ɵ(pronounced /k rbɑ ɵ
ha dre t/) is an organic compound withˈ ɪ ɪha dre t/) is an organic compound withˈ ɪ ɪ
the empirical formula Cthe empirical formula Cmm(H(H22O)O)nn (where(where mm
could be different fromcould be different from nn); that is,); that is,
consists only of carbon, hydrogen, andconsists only of carbon, hydrogen, and
oxygen, with a hydrogen:oxygen atomoxygen, with a hydrogen:oxygen atom
ratio of 2:1 (as in water).ratio of 2:1 (as in water).

4.  However, there are exceptions to this. OneHowever, there are exceptions to this. One
common example would be deoxyribose, acommon example would be deoxyribose, a
component of DNA, which has the empiricalcomponent of DNA, which has the empirical
formula Cformula C55HH1010OO44..
 Carbohydrates can be viewed as hydratesCarbohydrates can be viewed as hydrates
of carbon, hence their name. Structurallyof carbon, hence their name. Structurally
however, it is more accurate to view themhowever, it is more accurate to view them
as polyhydroxy aldehydes and ketones.as polyhydroxy aldehydes and ketones.

5. CarbohydratesCarbohydrates
 glucose provides energy for the brain and ½glucose provides energy for the brain and ½
of energy for muscles and tissuesof energy for muscles and tissues
 glycogen is stored glucoseglycogen is stored glucose
 glucose is immediate energyglucose is immediate energy
 glycogen is reserve energyglycogen is reserve energy

6. CarbohydratesCarbohydrates
 all plant foodall plant food
 milkmilk
 carbohydrates are not equalcarbohydrates are not equal
– simple carbohydratessimple carbohydrates
– complex carbohydratescomplex carbohydrates

7. Simple CarbohydratesSimple Carbohydrates
 sugarssugars
– monosaccharides – single sugarsmonosaccharides – single sugars
– disaccharides – 2 monosaccharidesdisaccharides – 2 monosaccharides

8. Complex CarbohydratesComplex Carbohydrates
 starches and fibersstarches and fibers
 polysaccharidespolysaccharides
– chains of monosaccharideschains of monosaccharides

9. Simple CarbsSimple Carbs
 monosaccharidesmonosaccharides
– all are 6 carbon hexesall are 6 carbon hexes
6 carbons6 carbons
12 hydrogens12 hydrogens
6 oxygens6 oxygens
arrangement differsarrangement differs
–accounts for varyingaccounts for varying
sweetnesssweetness
– glucose, fructose,glucose, fructose,
galactosegalactose

10. GlucoseGlucose
 mild sweet flavormild sweet flavor
 known as blood sugarknown as blood sugar
 essential energy sourceessential energy source
 found in everyfound in every
disaccharide anddisaccharide and
polysaccharidepolysaccharide

11. FructoseFructose
 sweetest sugarsweetest sugar
 found in fruits and honeyfound in fruits and honey
 added to soft drinks,added to soft drinks,
cereals, desertscereals, deserts

12. GalactoseGalactose
 hardly tastes sweethardly tastes sweet
 rarely foundrarely found
naturally as a singlenaturally as a single
sugarsugar

13. MonosaccharidesMonosaccharides
 Are the simplest carbohydrates that theyAre the simplest carbohydrates that they
cannot be hydrolyzed to smallercannot be hydrolyzed to smaller
carbohydrates.carbohydrates.
 They are aldehydes or ketones with two orThey are aldehydes or ketones with two or
more hydroxyl groups.more hydroxyl groups.
 The monosaccharides areThe monosaccharides are
dihydroxyacetone and D- & L-dihydroxyacetone and D- & L-
glyceraldehydes.glyceraldehydes.

14.  Monosaccharides are also classifiedMonosaccharides are also classified
according to three different characteristics:according to three different characteristics:
– The placement of its carbonyl groupThe placement of its carbonyl group
– The number of carbon atoms it containsThe number of carbon atoms it contains
– And its chiral handedness.And its chiral handedness.

15. The placement of its carbonylThe placement of its carbonyl
groupgroup
 If the carbonyl group is an aldehyde, theIf the carbonyl group is an aldehyde, the
monosaccharide is an aldosemonosaccharide is an aldose
 If the carbonyl group is a ketone, theIf the carbonyl group is a ketone, the
monosaccharide is a ketose.monosaccharide is a ketose.

16. The number of carbon atoms itThe number of carbon atoms it
containscontains
 Monosaccharides with three carbon atomsMonosaccharides with three carbon atoms
are called triosesare called trioses
 Those with four are called tetrose, five areThose with four are called tetrose, five are
called pentoses, six are hexoses and so on.called pentoses, six are hexoses and so on.
 For example, glucose, is an aldohexose ( aFor example, glucose, is an aldohexose ( a
six- carbon aldehyde); ribose is ansix- carbon aldehyde); ribose is an
aldopentose( a five- carbon aldehyde; &aldopentose( a five- carbon aldehyde; &
fructose is a ketohexose( a six- carbonfructose is a ketohexose( a six- carbon
ketone.ketone.

17. DisaccharidesDisaccharides
 pairs of the monosaccharidespairs of the monosaccharides
– glucose is always presentglucose is always present
– 22ndnd
of the pair could be fructose, galactoseof the pair could be fructose, galactose
or another glucoseor another glucose
– taken apart by hydrolysistaken apart by hydrolysis
– put together by condensationput together by condensation
– hydrolysis and condensation occur with allhydrolysis and condensation occur with all
energy nutrientsenergy nutrients
– maltose, sucrose, lactosemaltose, sucrose, lactose

18. CondensationCondensation
 making a disaccharidemaking a disaccharide
– chemical reaction linking 2chemical reaction linking 2
monosaccharidesmonosaccharides

19. HydrolysisHydrolysis
 breaking a disaccharidebreaking a disaccharide
– water molecule splitswater molecule splits
– occurs during digestionoccurs during digestion

20. MaltoseMaltose
 2 glucose units2 glucose units
 produced when starch breaks downproduced when starch breaks down
 not abundantnot abundant

21. SucroseSucrose
 fructose andfructose and
glucoseglucose
 tastes sweettastes sweet
– fruit, vegetables,fruit, vegetables,
grainsgrains
 table sugar istable sugar is
refined sugarcanerefined sugarcane
and sugar beetsand sugar beets
 brown, white,brown, white,
powderedpowdered

22. LactoseLactose
 glucose and galactoseglucose and galactose
 main carbohydrate inmain carbohydrate in
milkmilk
– known as milk sugarknown as milk sugar

23. Complex CarbohydratesComplex Carbohydrates
 polysaccharidespolysaccharides
– glycogen and starchglycogen and starch
built entirely of glucosebuilt entirely of glucose
– fiberfiber
variety of monosaccharides and othervariety of monosaccharides and other
carbohydrate derivativescarbohydrate derivatives

24. GlycogenGlycogen
 limited in meat and not found in plantslimited in meat and not found in plants
– not an important dietary source ofnot an important dietary source of
carbohydratecarbohydrate
 BUTBUT
– all glucose is stored as glycogenall glucose is stored as glycogen
– long chains allow forlong chains allow for
hydrolysis and releasehydrolysis and release
of energyof energy

25. StarchesStarches
 stored in plant cellsstored in plant cells
 body hydrolyzes plant starch to glucosebody hydrolyzes plant starch to glucose

26. FiberFiber
 structural parts of plantsstructural parts of plants
– found in all plant derived foodfound in all plant derived food
 bonds of fibers cannot be broken downbonds of fibers cannot be broken down
during the digestive processduring the digestive process
– minimal or no energy availableminimal or no energy available

27. Fiber typesFiber types
 cellulosecellulose
 pectinspectins
 ligninslignins
 resistant starchesresistant starches
– classified as fibersclassified as fibers
– escape digestion andescape digestion and
absorptionabsorption

28. Fiber CharacteristicsFiber Characteristics
 soluble fibers, viscous, fermentablesoluble fibers, viscous, fermentable
– easily digested by bacteria in coloneasily digested by bacteria in colon
– associated with protection against heartassociated with protection against heart
disease and diabetesdisease and diabetes
lower cholesterol and glucose levelslower cholesterol and glucose levels
– found in legumes and fruitsfound in legumes and fruits

29. FiberFiber
 insoluble and not easily fermentedinsoluble and not easily fermented
– promote bowel movementspromote bowel movements
– alleviate constipationalleviate constipation
– found in grains and vegetablesfound in grains and vegetables

30. DRI and FiberDRI and Fiber
 distinguish fibers by sourcedistinguish fibers by source
– dietary fibers: naturally in intact plantsdietary fibers: naturally in intact plants
– functional fibers: extracted from plants orfunctional fibers: extracted from plants or
manufacturedmanufactured
– total fiber: sum of the 2total fiber: sum of the 2

31. Carbohydrate DigestionCarbohydrate Digestion
 break down into glucosebreak down into glucose
– body is able to absorb and usebody is able to absorb and use
 large starch moleculeslarge starch molecules
– extensive breakdownextensive breakdown
 disaccharidesdisaccharides
– broken oncebroken once
 monosaccharidesmonosaccharides
– don’t need to be broken downdon’t need to be broken down

32. Carbohydrate DigestionCarbohydrate Digestion
 begins in mouthbegins in mouth
– chewing releases salivachewing releases saliva
– enzyme amylase hydrolyzes starch toenzyme amylase hydrolyzes starch to
polysaccharides and maltosepolysaccharides and maltose
 stomachstomach
– no enzymes available to break downno enzymes available to break down
starchstarch
– acid does some breakdownacid does some breakdown
– fibers in starch provide feeling of fullnessfibers in starch provide feeling of fullness

33.  small intestinesmall intestine
– majority of carbohydrate digestionmajority of carbohydrate digestion
takes place heretakes place here
– pancreatic amylase reduces carbs topancreatic amylase reduces carbs to
glucose chains or disaccharidesglucose chains or disaccharides
– specific enzymes finish the jobspecific enzymes finish the job
maltasemaltase
–maltose into 2 glucosemaltose into 2 glucose
sucrasesucrase
–sucrose into glucose and fructosesucrose into glucose and fructose
lactaselactase
–lactose into glucose andlactose into glucose and
galactosegalactose

34.  large intestinelarge intestine
– 1-4 hours for sugars and1-4 hours for sugars and
starches to be digestedstarches to be digested
– only fibers remainonly fibers remain
attract water, whichattract water, which
softens stoolsoftens stool
– bacteria ferment some fibersbacteria ferment some fibers
water, gas, short-chainwater, gas, short-chain
fatty acids (used forfatty acids (used for
energy)energy)

35. Carbohydrate AbsorptionCarbohydrate Absorption
 glucose can be absorbed in the mouthglucose can be absorbed in the mouth
 majority absorbed in small intestinemajority absorbed in small intestine
– active transportactive transport
glucose and galacticglucose and galactic
– facilitated diffusionfacilitated diffusion
fructosefructose
smaller rise in blood glucosesmaller rise in blood glucose

36. Lactose IntoleranceLactose Intolerance
 more lactose is consumed than can bemore lactose is consumed than can be
digesteddigested
– lactose molecules attract waterlactose molecules attract water
cause floating, abdominal discomfort,cause floating, abdominal discomfort,
diarrheadiarrhea
– intestinal bacteria feed on undigestedintestinal bacteria feed on undigested
lactoselactose
produce acid and gasproduce acid and gas

37. Lactose IntoleranceLactose Intolerance
 age, damage, medication, diarrhea,age, damage, medication, diarrhea,
malnutritionmalnutrition
 management requires dietary changemanagement requires dietary change
– 6 grams (1/2 cup) usually tolerable6 grams (1/2 cup) usually tolerable
– take in graduallytake in gradually
– hard cheeses & cottage cheesehard cheeses & cottage cheese
– enzyme drops or tabletsenzyme drops or tablets
 lactose free diet is extremely difficult tolactose free diet is extremely difficult to
accomplishaccomplish

39. Carbohydrate MetabolismCarbohydrate Metabolism
 1/3 of body’s glycogen is stored in liver1/3 of body’s glycogen is stored in liver
– released as glucose to bloodstreamreleased as glucose to bloodstream
1.1. eat – intake glucoseeat – intake glucose
2.2. liver condenses extra glucose to glycogenliver condenses extra glucose to glycogen
3.3. blood glucose fallsblood glucose falls
4.4. liver hydrolyzes glycogen to glucoseliver hydrolyzes glycogen to glucose
Glycogen is bulky, so we store only so much:Glycogen is bulky, so we store only so much:
short term energy supplyshort term energy supply
Fat is the long term energy supply.Fat is the long term energy supply.

40. Glucose for EnergyGlucose for Energy
 enzymes break apart glucose – yieldingenzymes break apart glucose – yielding
energyenergy
 inadequate supply of carbohydratesinadequate supply of carbohydrates
– ketone bodies (fat fragments) are anketone bodies (fat fragments) are an
alternate energy source during starvationalternate energy source during starvation
– excess ketones can lead to ketosis:excess ketones can lead to ketosis:
imbalance of acids in bodyimbalance of acids in body
 minimum of 50 – 100 grams of carbs/dayminimum of 50 – 100 grams of carbs/day
are needed to avoid ketosisare needed to avoid ketosis

41. Glucose HomeostasisGlucose Homeostasis
 maintaining an even balance of glucose ismaintaining an even balance of glucose is
controlled by insulin and glucagoncontrolled by insulin and glucagon
– insulininsulin
moves glucose into the bloodmoves glucose into the blood
– glucagonglucagon
brings glucose out of storagebrings glucose out of storage

42.  maintaining balancemaintaining balance
– balanced meals at regular intervalsbalanced meals at regular intervals
fiber and some fat slow the digestivefiber and some fat slow the digestive
process downprocess down
glucose gets into the blood slow andglucose gets into the blood slow and
steadysteady

43. Maintaining
Blood
Glucose
Homeostasis
Intestine
When a person eats,
blood glucose rises.
1
2
Insulin stimulates the uptake of
glucose into cells and storage
as glycogen in the liver and
muscles. Insulin also stimulates
the conversion of excess
glucose into fat for storage.
3
4
5
6
7 Blood glucose begins to
rise.
a
The stress hormone
epinephrine and other hormones
also bring glucose out of storage.
Glucose
Insulin
Glucagon
Glycogen
Glucagon stimulates liver
cells to break down glycogen
and release glucose into the
blood.a
Liver
Low blood glucose stimulates
the pancreas to release
glucagon into the bloodstream.
As the body's cells use
glucose, blood levels decline.
Glucagon
Pancreas
Fat cell
Liver
Muscle
High blood glucose stimulates
the pancreas to release insulin.
Pancreas
Insulin

44. ImbalanceImbalance
 diabetesdiabetes
– after food intake, blood glucose rises andafter food intake, blood glucose rises and
is not regulated because insulin isis not regulated because insulin is
inadequateinadequate
 hypoglycemiahypoglycemia
– blood glucose drops dramaticallyblood glucose drops dramatically
too much insulin, activity, inadequatetoo much insulin, activity, inadequate
food intake, illnessfood intake, illness
diet adjustment includes fiber-rich carbsdiet adjustment includes fiber-rich carbs
and proteinand protein

45. Glycemic IndexGlycemic Index
 way of classifyingway of classifying
food according tofood according to
their ability to raisetheir ability to raise
blood glucoseblood glucose
 much controversymuch controversy

46. Glycemic IndexGlycemic Index
 When it comes to choosing foods with theWhen it comes to choosing foods with the
ieda of minimizing blood glucose spikes,ieda of minimizing blood glucose spikes,
pure table sugar is better than a slice ofpure table sugar is better than a slice of
white bread, and much better than bakedwhite bread, and much better than baked
potato.potato.
 Keep in mind that this says nothing aboutKeep in mind that this says nothing about
the catual nutritional value of any food.the catual nutritional value of any food.
 It is ameasure of how quick foods tend toIt is ameasure of how quick foods tend to
raise blood glucose levels.raise blood glucose levels.

47.  What is surprising about what theWhat is surprising about what the
glycemic index shows is that someglycemic index shows is that some
foods rich in complex carbohydratesfoods rich in complex carbohydrates
like potatoes act very quickly to raiselike potatoes act very quickly to raise
blood sugar.blood sugar.
 On the other hand, complex starchesOn the other hand, complex starches
found in the legumes act slowly to raisefound in the legumes act slowly to raise
blood glucose level.blood glucose level.

48. SugarSugar
 ½ comes from natural sources, ½ from½ comes from natural sources, ½ from
refined and addedrefined and added
– sucrose, corn syrup, honeysucrose, corn syrup, honey
 excess can lead to nutrient deficienciesexcess can lead to nutrient deficiencies
and tooth decayand tooth decay
– empty caloriesempty calories
– sugar and starch break down in thesugar and starch break down in the
mouthmouth

49. SugarSugar
 recommended intakerecommended intake
– added sugar = no more than 10% of energyadded sugar = no more than 10% of energy
intakeintake

50. Starch and FiberStarch and Fiber
 diet that includes starch, fiber and naturaldiet that includes starch, fiber and natural
sugarssugars
– whole grains, vegetables, legumes, fruitswhole grains, vegetables, legumes, fruits
may protect against heart disease andmay protect against heart disease and
strokestroke
reduces the risk of type 2 diabetesreduces the risk of type 2 diabetes
enhances the health of the largeenhances the health of the large
intestineintestine
can promote weight losscan promote weight loss

51. Starch and FiberStarch and Fiber
 starch intakestarch intake
– 45-65%45-65%
– 225 – 325 grams (DV is 300225 – 325 grams (DV is 300
grams)grams)
– 900-1300 kcal/2000 kcal900-1300 kcal/2000 kcal
– RDA is 130 gramsRDA is 130 grams
 fiber intakefiber intake
– Daily Value is 25 grams/2000Daily Value is 25 grams/2000
kcalkcal

54. GroceriesGroceries
 grains: 1 serving = 15 gramsgrains: 1 serving = 15 grams
 vegetablesvegetables
– ½ cup starchy = 15 grams½ cup starchy = 15 grams
– ½ cup nonstarchy = 5 grams½ cup nonstarchy = 5 grams
 fruit: 1 serving = 15 gramsfruit: 1 serving = 15 grams
 milk: 1 cup = 12 gramsmilk: 1 cup = 12 grams
 meat: none or littlemeat: none or little
 legumes: ½ cup = 15 gramslegumes: ½ cup = 15 grams

55. Artificial SweetenersArtificial Sweeteners
 help keep sugar and energy intake downhelp keep sugar and energy intake down
 anything we eat has FDA approvalanything we eat has FDA approval
– saccharinsaccharin
– aspartameaspartame
– acesulfame potassiumacesulfame potassium
– sucralosesucralose
– neotameneotame

57. Sugar ReplacersSugar Replacers
 sugar alcoholssugar alcohols
– provide bulk and sweetnessprovide bulk and sweetness
cookies, gum, candy, jellycookies, gum, candy, jelly
– do contain minimal kcaldo contain minimal kcal
– low glycemic responselow glycemic response
absorbed slowlyabsorbed slowly
– do not cause dental cariesdo not cause dental caries