CarbohydratesCarbohydrates

Intended Learning Outcomes

- By the end of this lecture, students will have a

general overview on the carbohydrates.

Can you live without Can you live without sugar?sugar?

Soda/PunchSoda/Punch CookiesCookies CandyCandy ChocolateChocolate DessertsDesserts Sugary CerealsSugary Cereals Ice creamIce cream

CARBOHYDRATESCARBOHYDRATES

CarbsProteinFats

1. 60% of our food should come from carbohydrates.

2. Carbohydrates are 2. Carbohydrates are grainsgrains, , fruitsfruits, , vegetablesvegetables, , legumeslegumes

and and sugarsugar..

CarbohydratesCarbohydrates glucose provides energy for the glucose provides energy for the

brain and ½ of energy for brain and ½ of energy for muscles and tissuesmuscles and tissues

glycogen is stored glucoseglycogen is stored glucose glucose is immediate energyglucose is immediate energy glycogen is reserve energyglycogen is reserve energy

CARBOHYDRATESCARBOHYDRATES

33. Carbohydrates give . Carbohydrates give the body the body energyenergy. . They are the best They are the best source of source of fuelfuel for the for the body. Carbohydrates body. Carbohydrates also help to also help to digestdigest protein and fat. protein and fat.

CarbohydratesCarbohydrates 2. Carbohydrates also play a vital 2. Carbohydrates also play a vital

part of the part of the metabolismmetabolism and and oxidationoxidation of protein of protein

Carbs help feed the brain and Carbs help feed the brain and nervous system and helps keep the nervous system and helps keep the body lean.body lean.

CARBOHYDRATESCARBOHYDRATES

44. If we eat more . If we eat more carbohydrates than carbohydrates than are needed for are needed for energy, the extra is energy, the extra is stored in the liver or stored in the liver or in the tissues as in the tissues as fatfat..

CarbohydratesCarbohydrates 5. all 5. all plantplant food food Milk (Milk (LACTOSELACTOSE))

carbohydrates are not equalcarbohydrates are not equal

–simple carbohydratessimple carbohydrates

–complex carbohydratescomplex carbohydrates

Simple CarbohydratesSimple Carbohydrates6. 6. SimpleSimple carbohydrates are carbohydrates are quickquick

energy sources. They come from energy sources. They come from sugarsugar. They do not usually supply . They do not usually supply any other nutrients or fiber. any other nutrients or fiber.

Simple CarbohydratesSimple Carbohydrates sugarssugars

–monosaccharides – single sugarsmonosaccharides – single sugars

–disaccharides – 2 monosaccharidesdisaccharides – 2 monosaccharides

Simple CarbsSimple Carbs monosaccharidesmonosaccharides

–all are 6 carbon hexesall are 6 carbon hexes6 carbons6 carbons12 hydrogens12 hydrogens6 oxygens6 oxygensarrangement differsarrangement differs

–accounts for accounts for varying sweetnessvarying sweetness

–glucose, fructose, glucose, fructose, galactosegalactose

GlucoseGlucose mild sweet flavormild sweet flavor 10. known as blood 10. known as blood

sugarsugar essential energy essential energy

sourcesource found in every found in every

disaccharide and disaccharide and polysaccharidepolysaccharide

FructoseFructose sweetest sugarsweetest sugar found in fruits and found in fruits and

honeyhoney added to soft drinks, added to soft drinks,

cereals, desertscereals, deserts

GalactoseGalactose hardly tastes hardly tastes

sweetsweet rarely found rarely found

naturally as a naturally as a single sugar single sugar

DisaccharidesDisaccharides pairs of the monosaccharidespairs of the monosaccharides

–glucose is always presentglucose is always present–22ndnd of the pair could be fructose, of the pair could be fructose,

galactose or another glucosegalactose or another glucose– taken apart by hydrolysistaken apart by hydrolysis–put together by condensationput together by condensation–hydrolysis and condensation occur hydrolysis and condensation occur

with all energy nutrientswith all energy nutrients–maltose, sucrose, lactosemaltose, sucrose, lactose

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

SucroseSucrose fructose and glucosefructose and glucose tastes sweettastes sweet

–fruit, vegetables, fruit, vegetables, grainsgrains

table sugar is refined table sugar is refined sugarcane and sugarcane and sugar beetssugar beets

brown, brown, white ,powderedwhite ,powdered

LactoseLactose glucose and galactoseglucose and galactose main carbohydrate in main carbohydrate in

milkmilk

– known as milk sugarknown as milk sugar

Simple SugarsSimple Sugars77. . GlucoseGlucose or blood sugar is the or blood sugar is the

basic source of energy for all basic source of energy for all living things. living things.

8. 8. SucroseSucrose or table sugar is made or table sugar is made from sugar beets or sugar from sugar beets or sugar cane. cane.

9. 9. FructoseFructose is sugar found in fruit, is sugar found in fruit, honey and vegetables. honey and vegetables.

11. 11. MaltoseMaltose is grain starch broken is grain starch broken down into sugar.down into sugar.

12. 12. LactoseLactose is milk sugar. is milk sugar.

Complex CarbohydratesComplex Carbohydrates starches and fibersstarches and fibers polysaccharidespolysaccharides

–chains of monosaccharideschains of monosaccharides

Complex Complex CarbohydratesCarbohydrates

1313. . ComplexComplex carbohydrates supply carbohydrates supply longer lastinglonger lasting energy, energy, as well as other as well as other nutrients and fiber that nutrients and fiber that the body needs. They the body needs. They are a better choice. are a better choice.

CondensationCondensation making a making a

disaccharidedisaccharide

–chemical reaction chemical reaction linking 2 linking 2 monosaccharidesmonosaccharides

HydrolysisHydrolysis breaking a disaccharidebreaking a disaccharide

–water molecule splitswater molecule splits

–occurs during digestionoccurs during digestion

Complex CarbohydratesComplex Carbohydrates polysaccharidespolysaccharides

–1.glycogen and 2.starch1.glycogen and 2.starchbuilt entirely of glucosebuilt entirely of glucose

–3.fiber3.fibervariety of monosaccharides and variety of monosaccharides and other carbohydrate derivativesother carbohydrate derivatives

GlycogenGlycogen limited in meat and not found in plantslimited in meat and not found in plants

–not an important dietary source of not an important dietary source of carbohydratecarbohydrate

BUTBUT–all glucose is stored as glycogenall glucose is stored as glycogen– long chains allow for long chains allow for hydrolysis and releasehydrolysis and release of energyof energy

StarchesStarches stored in plant cellsstored in plant cells body hydrolyzes plant starch to body hydrolyzes plant starch to

glucoseglucose

STARCHESSTARCHES 1414. . StarchStarch in the body breaks down in the body breaks down

simple sugars. The body has to break simple sugars. The body has to break down all sugar and down all sugar and starchstarch into glucose into glucose to use itto use it..

Starchy FoodsStarchy Foods15. All starchy foods are 15. All starchy foods are

plant foods, plant foods, seedsseeds are the are the richest source; 70% of their richest source; 70% of their weight is starchweight is starch

FiberFiber structural parts of plantsstructural parts of plants

–found in all plant derived foodfound in all plant derived food bonds of fibers cannot be bonds of fibers cannot be

broken down during the broken down during the digestive processdigestive process

–minimal or no energy availableminimal or no energy available

Fiber typesFiber types

cellulosecellulose

pectinspectins ligninslignins resistant starchesresistant starches

– classified as fibersclassified as fibers

– escape digestion and escape digestion and absorptionabsorption

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 associated with protection against

heart disease and diabetesheart disease and diabetes lower cholesterol and glucose levelslower cholesterol and glucose levels

– found in legumes and found in legumes and fruits fruits

FiberFiber1.1. The average American does not get The average American does not get

enough enough FIBERFIBER in their diets. in their diets.

2.2. The National Cancer Institute The National Cancer Institute recommends that the average recommends that the average person gets person gets 20-35 GRAMS 20-35 GRAMS of fiber of fiber every day. every day.

3.3. Two other common names for fiber Two other common names for fiber are: are: ROUGHAGEROUGHAGE or or CELLULOSE.CELLULOSE.

4.4. Fiber is important because it attracts Fiber is important because it attracts WATER WATER to the to the INTESTINESINTESTINES and helps and helps move food through our systems faster. move food through our systems faster. You have to have water along with fiber You have to have water along with fiber or it is not as effective.or it is not as effective.

5.5. Benefits of fiber include a lowered risk Benefits of fiber include a lowered risk of of DIVERTICULITUSDIVERTICULITUS, , HEMORRHOIDSHEMORRHOIDS and and COLONCOLON or or RECAL CANCERRECAL CANCER. .

6. List the two types of fiber and the main 6. List the two types of fiber and the main functions they perform: functions they perform:

7.7. Fiber only comes from Fiber only comes from PLANT PLANT food food sources. You CANNOT get fiber from sources. You CANNOT get fiber from animal food sources. animal food sources.

8.8. Foods that are high in fiber include:Foods that are high in fiber include:

• Fruits and Veggies (Especially the Fruits and Veggies (Especially the Skins!)Skins!)

• Whole GrainsWhole Grains

• Legumes/Beans - BranLegumes/Beans - Bran

9.9. Ways to increase fiber in the diet include:Ways to increase fiber in the diet include:

• Add Whole Grains (At least 3 oz. per Add Whole Grains (At least 3 oz. per day)day)

• Use Whole Wheat FlourEat the SkinsUse Whole Wheat FlourEat the Skins

10. Label the Wheat Kernel below:10. Label the Wheat Kernel below:A.__ENDOSPERM___

Provides:

Starch

Protein

B. __GERM___

Provides:

Unsaturated Fatty Acids

“B” Vitamins

Vitamin E

Iron

Zinc

Other Trace Minerals

C. __Bran___

Provides:

Fiber

Vitamins

Minerals

11.11.When a product claims that it is “Whole When a product claims that it is “Whole Wheat” or “Whole Grain”, it must use the Wheat” or “Whole Grain”, it must use the ENTIREENTIRE wheat kernel, or wheat kernel, or ALL THREE ALL THREE parts. parts.

12.12.Other products, like white bread and Other products, like white bread and rice, usually only use the rice, usually only use the ENDOSPERMENDOSPERM, , which is the which is the LEASTLEAST beneficial part of the beneficial part of the wheat kernel. wheat kernel.

13.13.ENRICHEDENRICHED: some of the nutrients that : some of the nutrients that were lost in processing are added back were lost in processing are added back into the product. into the product.

14.14.FORTIFIEDFORTIFIED: 10% more of the Daily : 10% more of the Daily Value for the nutrient is being added. Value for the nutrient is being added.

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

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 or functional fibers: extracted from plants or manufacturedmanufactured

– total fiber: sum of the 2total fiber: sum of the 2

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

Carbohydrate DigestionCarbohydrate Digestion begins in mouthbegins in mouth

– chewing releases salivachewing releases saliva

– enzyme amylase hydrolyzes starch to enzyme amylase hydrolyzes starch to polysaccharides and maltosepolysaccharides and maltose

stomachstomach

– no enzymes available to break down no 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

small intestine majority of carbohydrate digestion takes place herepancreatic amylase reduces carbs to glucose chains or disaccharidesspecific enzymes finish the job

maltasemaltose into 2 glucose

sucrasesucrose into glucose and fructose

lactaselactose into glucose and galactose

large intestine

1-4 hours for sugars and starches to be digested only fibers remain

attract water, which softens stoolbacteria ferment some fibers

water, gas, short-chain fatty acids (used for energy)

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 transportglucose and galacticglucose and galactic

– facilitated diffusion facilitated diffusion fructosefructosesmaller rise in blood glucosesmaller rise in blood glucose

Lactose IntoleranceLactose Intolerance more lactose is consumed than can be more lactose is consumed than can be

digesteddigested

– lactose molecules attract waterlactose molecules attract watercause floating, abdominal discomfort, cause floating, abdominal discomfort,

diarrheadiarrhea

– intestinal bacteria feed on undigested intestinal bacteria feed on undigested lactoselactoseproduce acid and gasproduce acid and gas

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 to lactose free diet is extremely difficult to

accomplishaccomplish

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 bloodstream1.1. eat – intake glucoseeat – intake glucose2.2. liver condenses extra glucose to glycogenliver condenses extra glucose to glycogen3.3. blood glucose fallsblood glucose falls4.4. 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.

Glucose for EnergyGlucose for Energy

enzymes break apart glucose – yielding enzymes break apart glucose – yielding energyenergy

inadequate supply of carbohydratesinadequate supply of carbohydrates– ketone bodies (fat fragments) are an ketone 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/day minimum of 50 – 100 grams of carbs/day

are needed to avoid ketosisare needed to avoid ketosis

Glucose HomeostasisGlucose Homeostasis

maintaining an even balance of glucose is maintaining an even balance of glucose is controlled by insulin and glucagoncontrolled by insulin and glucagon

– insulininsulinmoves glucose into the bloodmoves glucose into the blood

– glucagonglucagonbrings glucose out of storagebrings glucose out of storage

maintaining balancebalanced meals at regular intervals

fiber and some fat slow the digestive process downglucose gets into the blood slow and steady

Maintaining Blood

Glucose Homeostasis

Intestine When a person eats,blood glucose rises.

1

2

Insulin stimulates the uptake of glucose into cells and storageas glycogen in the liver and muscles. Insulin also stimulates the conversion of excessglucose into fat for storage.

3

4

5

6

7Blood glucose begins to rise.

a The stress hormone epinephrine and other hormonesalso bring glucose out of storage.

GlucoseInsulinGlucagonGlycogen

Glucagon stimulates livercells to break down glycogenand release glucose into theblood.a

Liver

Low blood glucose stimulatesthe pancreas to releaseglucagon into the bloodstream.

As the body's cells useglucose, blood levels decline.

Glucagon

Pancreas

Fat cell

Liver

Muscle

High blood glucose stimulatesthe pancreas to release insulin.

Pancreas

Insulin

ImbalanceImbalance

diabetesdiabetes– after food intake, blood glucose rises and after food intake, blood glucose rises and

is not regulated because insulin is is not regulated because insulin is inadequateinadequate

hypoglycemiahypoglycemia– blood glucose drops dramaticallyblood glucose drops dramatically

too much insulin, activity, inadequate too much insulin, activity, inadequate food intake, illnessfood intake, illness

diet adjustment includes fiber-rich carbs diet adjustment includes fiber-rich carbs and proteinand protein

Glycemic IndexGlycemic Index

way of classifying way of classifying food according to food according to their ability to raise their ability to raise blood glucoseblood glucose

much controversymuch controversy

SugarSugar

½ comes from natural sources, ½ from ½ comes from natural sources, ½ from refined and addedrefined and added

– sucrose, corn syrup, honeysucrose, corn syrup, honey excess can lead to nutrient deficiencies excess can lead to nutrient deficiencies

and tooth decayand tooth decay

– empty caloriesempty calories

– sugar and starch break down in the sugar and starch break down in the mouthmouth

SugarSugar

recommended intakerecommended intake

– added sugar = no more than 10% of energy added sugar = no more than 10% of energy intakeintake

Starch and FiberStarch and Fiber

diet that includes starch, fiber and natural diet that includes starch, fiber and natural sugarssugars

– whole grains, vegetables, legumes, fruitswhole grains, vegetables, legumes, fruitsmay protect against heart disease and may protect against heart disease and

strokestroke reduces the risk of type 2 diabetesreduces the risk of type 2 diabetesenhances the health of the large enhances the health of the large

intestineintestinecan promote weight losscan promote weight loss

Starch and FiberStarch and Fiber starch intakestarch intake

– 45-65%45-65%

– 225 – 325 grams (DV is 300 225 – 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/2000 Daily Value is 25 grams/2000 kcalkcal

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

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

Sugar ReplacersSugar Replacers

sugar alcoholssugar alcohols

– provide bulk and sweetnessprovide bulk and sweetnesscookies, gum, candy, jellycookies, gum, candy, jelly

– do contain minimal kcaldo contain minimal kcal

– low glycemic responselow glycemic responseabsorbed slowlyabsorbed slowly

– do not cause dental cariesdo not cause dental caries

Assignment Taghreed MahmoudTaghreed Mahmoud Sohila nabil hamedSohila nabil hamed

Recommended text book

Manual dietetic book