Nutrition and Metabolism

Nutrition and MetabolismNutrition and Metabolism

Critical Thinking Question:Critical Thinking Question:Why does your body need food?Why does your body need food?

Answer:Answer:

Food has two main functions:Food has two main functions:

1)1) Food provides raw materials for cells to Food provides raw materials for cells to build new molecules for growth and build new molecules for growth and reproductionreproduction

2)2) Food provides energyFood provides energy

NutrientsNutrients

• Many cells of the body (ex. liver cells) Many cells of the body (ex. liver cells) can convert one molecule into another can convert one molecule into another based on what is neededbased on what is needed

• Essential nutrients: must be provided by Essential nutrients: must be provided by the diet because they can’t be created the diet because they can’t be created through conversionsthrough conversions

NutritionNutrition Nutrient: substance used by the body

for growth, maintenance, and repair

Categories of nutrients: Carbohydrates

Lipids

Proteins

Vitamins

Minerals

Water

Major NutrientsMajor Nutrients

Dietary Sources of CarbohydratesDietary Sources of Carbohydrates Most are derived from plantsMost are derived from plants

Sugars (fruits) and starches (vegetables) Sugars (fruits) and starches (vegetables)

Exceptions: lactose from milk and small amounts of Exceptions: lactose from milk and small amounts of glycogens from meatsglycogens from meats

Body Uses of CarbohydratesBody Uses of Carbohydrates

Preferred source (esp. glucose) to Preferred source (esp. glucose) to produce cellular energy (ATP)produce cellular energy (ATP)

Examples: neurons and red blood cellsExamples: neurons and red blood cells

Dietary Requirements of CarbohydratesDietary Requirements of Carbohydrates

• 125-175 grams/day (mainly complex 125-175 grams/day (mainly complex carbohydrates)carbohydrates)

• Complex carbohydrates – bread, cereal, rice, Complex carbohydrates – bread, cereal, rice, potatoespotatoes

• ““Strive for Five” – servings of fruits and Strive for Five” – servings of fruits and vegetables per dayvegetables per day

Dietary Requirements of CarbohydratesDietary Requirements of Carbohydrates

Excesses:Excesses:• ObesityObesity• Nutritional deficits Nutritional deficits

(“empty calories”)(“empty calories”)• Gastrointestinal Gastrointestinal

problems problems (constipation)(constipation)

Deficits:Deficits:• Tissue wasting Tissue wasting

(muscle breakdown)(muscle breakdown)• Metabolic acidosis Metabolic acidosis

(fat breakdown)(fat breakdown)

Dietary Sources of LipidsDietary Sources of Lipids Saturated fats from animal products Saturated fats from animal products

(meat and dairy)(meat and dairy)

Unsaturated fats from nuts, seeds, and Unsaturated fats from nuts, seeds, and vegetable oilsvegetable oils

Cholesterol from egg yolk, meats, and Cholesterol from egg yolk, meats, and milk productsmilk products

Trans fatsTrans fats

• ““Healthy” vegetable oils that have been Healthy” vegetable oils that have been “hydrogenated” to make them more solid“hydrogenated” to make them more solid

• Used in many snack and junk foodsUsed in many snack and junk foods• Increases shelf life of foods (they don’t get Increases shelf life of foods (they don’t get

rancid)rancid)• Have the most negative effect on cholesterol Have the most negative effect on cholesterol

– raises the bad, lowers the good– raises the bad, lowers the good

Body Uses of LipidsBody Uses of Lipids Help body absorb fat-soluble vitaminsHelp body absorb fat-soluble vitamins

Major energy fuel for liver cells and skeletal Major energy fuel for liver cells and skeletal musclemuscle

Main component of ALL cell membranesMain component of ALL cell membranes

Adipose tissue protects organs, provides Adipose tissue protects organs, provides insulation, and stores energyinsulation, and stores energy

Cholesterol is necessary to make hormones Cholesterol is necessary to make hormones and bileand bile

Dietary Requirements of LipidsDietary Requirements of Lipids 30% or less of total caloric intake30% or less of total caloric intake

Saturated fats should be less than 10% of total Saturated fats should be less than 10% of total caloriescalories

Cholesterol should be less than 250 mg (ex. one Cholesterol should be less than 250 mg (ex. one egg yolk)egg yolk)

Dietary Requirements of LipidsDietary Requirements of Lipids

Excesses:Excesses:• ObesityObesity• Increased risk of Increased risk of

cardiovascular cardiovascular diseasedisease

Deficits:Deficits:• Weight lossWeight loss• Difficulty with Difficulty with

temperature temperature regulationregulation

• Poor growth/repairPoor growth/repair

Fat SubstitutesFat Substitutes

• Modified starches or proteinsModified starches or proteins• Some are metabolized, but some are Some are metabolized, but some are

not because they cannot be absorbednot because they cannot be absorbed• Drawbacks:Drawbacks:

1.1. Typically don’t stand up to heat for fryingTypically don’t stand up to heat for frying2.2. Don’t taste the same as real fatDon’t taste the same as real fat3.3. May cause GI disturbances (ex. diarrhea)May cause GI disturbances (ex. diarrhea)4.4. May interfere with the absorption of fat-May interfere with the absorption of fat-

soluble drugs and vitaminssoluble drugs and vitamins

Dietary Sources of ProteinsDietary Sources of Proteins Most complete proteins come from animal Most complete proteins come from animal

products (eggs, milk, meat)products (eggs, milk, meat)

Complete proteins: contain all essential Complete proteins: contain all essential amino acidsamino acids

Legumes (beans and peas), nuts, leafy Legumes (beans and peas), nuts, leafy greens also have proteins, but are incompletegreens also have proteins, but are incomplete

Incomplete proteins: missing or low in one Incomplete proteins: missing or low in one or more of the essential amino acidsor more of the essential amino acids

Body Uses of ProteinsBody Uses of Proteins Major component of structural materials Major component of structural materials

(skin, nails, muscles)(skin, nails, muscles)

Regulate chemical reactions (enzymes)Regulate chemical reactions (enzymes)

Dietary Requirements of ProteinsDietary Requirements of Proteins Depends on age, size, and metabolic rateDepends on age, size, and metabolic rate

0.8 grams per kilogram of body weight0.8 grams per kilogram of body weight

General conversion – divide weight in General conversion – divide weight in pounds by 3 to equal the number of grams pounds by 3 to equal the number of grams neededneeded

Dietary Requirements of ProteinsDietary Requirements of Proteins

Excesses:Excesses:• ObesityObesity• Aggravation of Aggravation of

chronic diseasechronic disease

Deficits:Deficits:• Profound weight Profound weight

loss and tissue loss and tissue wastingwasting

• Poor growth/repairPoor growth/repair• AnemiaAnemia

VitaminsVitamins Most vitamins are used as coenzymes, Most vitamins are used as coenzymes,

helping enzymes with their chemical helping enzymes with their chemical reactionsreactions

Most must be ingested – the body can only Most must be ingested – the body can only make Vitamins A, B, D, and Kmake Vitamins A, B, D, and K

VitaminsVitamins Two main categories:Two main categories:

1.1. Water-soluble: absorbed with water, not Water-soluble: absorbed with water, not stored in the body, excreted in the urine if stored in the body, excreted in the urine if not usednot used

2.2. Fat-soluble: absorbed with fats, stored in Fat-soluble: absorbed with fats, stored in the body, excesses can lead to toxicitythe body, excesses can lead to toxicity

MineralsMinerals Body requires moderate amounts of 7 minerals Body requires moderate amounts of 7 minerals

(Ca, P, K, S, Na, Cl, Mg) and trace amounts of (Ca, P, K, S, Na, Cl, Mg) and trace amounts of about 12 othersabout 12 others

Make up 4% of the body weight, mostly due to Make up 4% of the body weight, mostly due to Ca and P in bonesCa and P in bones

Provide strength to certain structuresProvide strength to certain structures

MineralsMinerals Vital components to many biological compounds Vital components to many biological compounds

(ex. iron (Fe) in hemoglobin)(ex. iron (Fe) in hemoglobin)

Important electrolytes (sodium/chloride ions)Important electrolytes (sodium/chloride ions)

Found in mostly vegetables, legumes, milk, and Found in mostly vegetables, legumes, milk, and meatsmeats

MetabolismMetabolism Definition: all chemical reactions Definition: all chemical reactions

necessary to maintain lifenecessary to maintain life

1)1) Catabolism – substances are broken down Catabolism – substances are broken down to simpler substancesto simpler substances

Energy (ATP) is released from food Energy (ATP) is released from food during a catabolic process called during a catabolic process called cellular cellular respirationrespiration

MetabolismMetabolism2)2) Anabolism – larger molecules are built from Anabolism – larger molecules are built from smaller onessmaller ones

Tissue growth and repairTissue growth and repair

Storage molecules (ex. glycogen)Storage molecules (ex. glycogen)

Three Major Stages of MetabolismThree Major Stages of Metabolism

Stage 1:Stage 1:

• Occurs in the digestive tractOccurs in the digestive tract

• Absorbed nutrients are transported to Absorbed nutrients are transported to cells through the bloodcells through the blood


Stage 2:Stage 2:

• Occurs in the cytoplasm of body cellsOccurs in the cytoplasm of body cells

a) Nutrients are built into cellular a) Nutrients are built into cellular molecules (anabolism)molecules (anabolism)

b) Nutrients are broken down into ATP b) Nutrients are broken down into ATP without oxygen (catabolism) without oxygen (catabolism)

a.k.a. a.k.a. GLYCOLYSISGLYCOLYSIS


Stage 3:Stage 3:

• Occurs in the mitochondria of body Occurs in the mitochondria of body cellscells

• Nutrients are broken down into ATP Nutrients are broken down into ATP (catabolism) in the (catabolism) in the presence of presence of oxygen a.k.a. CELLULAR oxygen a.k.a. CELLULAR RESPIRATIONRESPIRATION

Cellular RespirationCellular Respiration

• Series of reactions that breaks down food Series of reactions that breaks down food molecules to create ATP molecules to create ATP

• Must occur in a series of steps or else Must occur in a series of steps or else energy would be released as a blast of energy would be released as a blast of energyenergy

• ATP is the ONLY energy cells can directly ATP is the ONLY energy cells can directly useuse

• Cells release carbon dioxide (COCells release carbon dioxide (CO22) and ) and

water (Hwater (H22O) as a result of the reactions O) as a result of the reactions

General Equation for Cellular RespirationGeneral Equation for Cellular Respiration


• Two separate pathways, BOTH start with Two separate pathways, BOTH start with GLYCOLYSIS (NO OXYGEN NEEDED)GLYCOLYSIS (NO OXYGEN NEEDED)

• Glycolysis is the first step, but only extracts Glycolysis is the first step, but only extracts 10% of energy from glucose – only 2 ATP per 10% of energy from glucose – only 2 ATP per reaction!reaction!

• Remaining 90% of energy is still locked in an Remaining 90% of energy is still locked in an intermediate molecule (pyruvic acid) made intermediate molecule (pyruvic acid) made from glucosefrom glucose


Presence or lack of oxygen determines the next step:Presence or lack of oxygen determines the next step:

1)1) To continue WITHOUT OXYGEN (Anaerobic): To continue WITHOUT OXYGEN (Anaerobic): Lactic Acid FermentationLactic Acid Fermentation

2)2) To continue WITH OXYGEN (Aerobic): To continue WITH OXYGEN (Aerobic):


Lactic Acid FermentationLactic Acid Fermentation• Glycolysis can make ATP really fast, but if there is Glycolysis can make ATP really fast, but if there is

no oxygen, it proceeds to lactic acid fermentationno oxygen, it proceeds to lactic acid fermentation

• In muscle cells, lactic acid builds up and then is In muscle cells, lactic acid builds up and then is removed by blood to the liver (i.e. muscle soreness removed by blood to the liver (i.e. muscle soreness after vigorous exercise)after vigorous exercise)

• In the liver, it will be converted to a useable energy In the liver, it will be converted to a useable energy molecule when oxygen is availablemolecule when oxygen is available


• When oxygen is available, glucose is further broken When oxygen is available, glucose is further broken down in the mitochondria to make ATPdown in the mitochondria to make ATP

• Slightly longer process, but yields almost 20x the Slightly longer process, but yields almost 20x the amount of ATP as glycolysisamount of ATP as glycolysis

• Remaining 90% of energy is released by two steps:Remaining 90% of energy is released by two steps:

1) Krebs cycle1) Krebs cycle

2) Electron Transport Chain (ETC)2) Electron Transport Chain (ETC)

Metabolic Pathways Involved in Metabolic Pathways Involved in Cellular RespirationCellular Respiration

Figure 14.17

ATP: The TotalsATP: The Totals• Without oxygenWithout oxygen: the cell can produce : the cell can produce only 2 only 2

ATPATP molecules during glycolysis molecules during glycolysis

• With oxygenWith oxygen: the cell can produce : the cell can produce 36 more ATP36 more ATP in the Krebs cycle and ETC in the Krebs cycle and ETC

Final Total: 38 ATP from 1 glucoseFinal Total: 38 ATP from 1 glucose

• Cellular respiration extracts 38% of energy from Cellular respiration extracts 38% of energy from glucose – the rest is lost as ???glucose – the rest is lost as ???

Why settle for only 38%?Why settle for only 38%?

Answer:Answer:If glucose were burned If glucose were burned

directly in air, 100% of the directly in air, 100% of the energy would be in the formenergy would be in the form

of heat and light, which the human of heat and light, which the human body cannot use. So, 38% is actually body cannot use. So, 38% is actually

pretty efficient!!pretty efficient!!

Metabolism of Specific NutrientsMetabolism of Specific Nutrients

Carbohydrate MetabolismCarbohydrate Metabolism

• Most carbohydrates are eventually Most carbohydrates are eventually transformed to glucose to create ATP through transformed to glucose to create ATP through cellular respirationcellular respiration

• Too much glucose (supply > demand) leads Too much glucose (supply > demand) leads to glycogenesisto glycogenesis

• Glycogenesis: conversion of glucose to glycogen to be Glycogenesis: conversion of glucose to glycogen to be stored in the liver and skeletal musclesstored in the liver and skeletal muscles

• Too little glucose (supply < demand) leads to Too little glucose (supply < demand) leads to glycogenolysisglycogenolysis

• Glycogenolysis: glycogen stored in the liver is converted Glycogenolysis: glycogen stored in the liver is converted back to glucose and released into the bloodback to glucose and released into the blood

Fat MetabolismFat Metabolism Fats make up 78% of energy reservesFats make up 78% of energy reserves

Broken down into fatty acids and glycerol Broken down into fatty acids and glycerol which go through various stages in cellular which go through various stages in cellular respiration to make ATPrespiration to make ATP

Body cells remove fat and cholesterol to Body cells remove fat and cholesterol to build membranes and steroid hormonesbuild membranes and steroid hormones

Excess fatty acids and glycerol are Excess fatty acids and glycerol are converted to triglycerides through converted to triglycerides through lipogenesislipogenesis

Fat Metabolism: Cholesterol TransportFat Metabolism: Cholesterol Transport

Cholesterol and fatty acids cannot freely Cholesterol and fatty acids cannot freely circulate in the bloodstreamcirculate in the bloodstream

They are transported by lipoproteins (lipid-They are transported by lipoproteins (lipid-protein complexes) made by the liverprotein complexes) made by the liver

Low-density lipoproteins (LDLs) transport from Low-density lipoproteins (LDLs) transport from liver to body cells (“bad” cholesterol)liver to body cells (“bad” cholesterol)

High-density lipoproteins (HDLs) transport from High-density lipoproteins (HDLs) transport from body cells to the liver (“good” cholesterol)body cells to the liver (“good” cholesterol)

FACTFACT

You need very little cholesterol in your You need very little cholesterol in your diet because most of the cholesterol that diet because most of the cholesterol that

your body needs is made in the liver!your body needs is made in the liver!

Protein MetabolismProtein Metabolism Ingested proteins are broken down to Ingested proteins are broken down to

amino acidsamino acids

Cells remove amino acids to build proteins Cells remove amino acids to build proteins (cell structures and enzymes)(cell structures and enzymes)

Excess amino acids are used for energy or Excess amino acids are used for energy or converted into fat for storageconverted into fat for storage

Amino acids are used to make ATP only Amino acids are used to make ATP only when proteins are overabundant or there when proteins are overabundant or there is a shortage of other sourcesis a shortage of other sources

Protein Metabolism:Protein Metabolism:

Production of ATP from ProteinsProduction of ATP from Proteins

Amine groups are removed from proteins Amine groups are removed from proteins as ammoniaas ammonia

The rest of the protein molecule enters the The rest of the protein molecule enters the Krebs cycle in mitochondriaKrebs cycle in mitochondria

The liver converts harmful ammonia to The liver converts harmful ammonia to urea which can be eliminated in urineurea which can be eliminated in urine

Catabolic-Anabolic Steady State of the BodyCatabolic-Anabolic Steady State of the Body

ABSORPTIVE STATE:ABSORPTIVE STATE:

• During and shortly after eatingDuring and shortly after eating

• Focus is ANABOLISM and ENERGY Focus is ANABOLISM and ENERGY STORAGESTORAGE

Catabolic-Anabolic Steady State of the BodyCatabolic-Anabolic Steady State of the Body

POST-ABSORPTIVE STATE:POST-ABSORPTIVE STATE:

• When the GI tract is emptyWhen the GI tract is empty

• Focus is CATABOLISM and FUEL Focus is CATABOLISM and FUEL REPLACEMENT IN BLOODREPLACEMENT IN BLOOD

Question: What are the roles of the Question: What are the roles of the liver in metabolism?liver in metabolism?

Answers:Answers:

1.1. Several roles in digestion (bile)Several roles in digestion (bile)

2.2. Detoxifies drugs and alcoholDetoxifies drugs and alcohol

3.3. Produce cholesterol, blood proteins Produce cholesterol, blood proteins (albumin and clotting proteins)(albumin and clotting proteins)

4.4. Gluconeogenesis: glucose is produced Gluconeogenesis: glucose is produced from fats and proteinsfrom fats and proteins

Critical Thinking Question: How Critical Thinking Question: How does the body increase blood does the body increase blood

glucose levels without ingesting glucose levels without ingesting additional food?additional food?

Answer: Glycogenolysis and Answer: Glycogenolysis and gluconeogenesis!gluconeogenesis!

Energy and ExerciseEnergy and ExerciseQuick energy:Quick energy:

• Stored ATP – 10 seconds of energyStored ATP – 10 seconds of energy• Lactic Acid Fermentation – 90 seconds of Lactic Acid Fermentation – 90 seconds of

energyenergy• This creates an oxygen debt - heavy This creates an oxygen debt - heavy

breathing is required to get rid of lactic acid breathing is required to get rid of lactic acid build upbuild up

Energy and ExerciseEnergy and Exercise

Long term energy:Long term energy:• Cellular Respiration - breaks down glycogen, Cellular Respiration - breaks down glycogen,

which has enough stored for 15-20 minutes which has enough stored for 15-20 minutes of constant activityof constant activity• After 20 minutes, when body runs out of After 20 minutes, when body runs out of

glycogen, it breaks down fatglycogen, it breaks down fat• Pacing is necessary because cell Pacing is necessary because cell

respiration releases energy more slowly respiration releases energy more slowly than the other processesthan the other processes

Amount of Energy in FoodAmount of Energy in Food

• 1 gram of glucose = 3811 calories of heat 1 gram of glucose = 3811 calories of heat energyenergy

• ccalorie: the amount of energy needed to raise 1 alorie: the amount of energy needed to raise 1 gram of water 1gram of water 1°C°C

• CCalorie (kilocalorie):alorie (kilocalorie): food calorie = 1000 caloriesfood calorie = 1000 calories• 1 gram of FAT = 9 Calories1 gram of FAT = 9 Calories• 1 gram of CARBOHYDRATE or PROTEIN = 4 1 gram of CARBOHYDRATE or PROTEIN = 4

CaloriesCalories

FACTFACT

One pound of fat equals 3500 Calories.One pound of fat equals 3500 Calories.

Regulation of Food IntakeRegulation of Food Intake

1.1. Levels of nutrients in the bloodLevels of nutrients in the blood

2.2. HormonesHormones

3.3. Body temperatureBody temperature

4.4. Psychological factorsPsychological factors

Basal Metabolic RateBasal Metabolic Rate

Basic metabolic rate (BMR) – amount Basic metabolic rate (BMR) – amount of heat produced by the body per unit of heat produced by the body per unit of time at rest (energy used to perform of time at rest (energy used to perform ESSENTIAL activities)ESSENTIAL activities)

Heat is energy out as a result of Heat is energy out as a result of cellular activitiescellular activities

Factors that Affect BMRFactors that Affect BMR

1.1. Age – children and adolescents have a Age – children and adolescents have a higher BMRhigher BMR

2.2. More thyroxine produced means higher More thyroxine produced means higher metabolic rate (most important control metabolic rate (most important control factor)factor)

3.3. Surface area – small body usually has Surface area – small body usually has higher BMRhigher BMR

4.4. Gender – males tend to have higher Gender – males tend to have higher BMRBMR

Total Metabolic Rate (TMR)Total Metabolic Rate (TMR) Total amount of kilocalories the body Total amount of kilocalories the body

must consume to fuel ongoing activitiesmust consume to fuel ongoing activities

TMR increases with an increase in body TMR increases with an increase in body activityactivity

TMR must equal calories consumed to TMR must equal calories consumed to maintain homeostasis and maintain a maintain homeostasis and maintain a constant weightconstant weight

Body weight is usually relatively stable if Body weight is usually relatively stable if energy intake and output remain equalenergy intake and output remain equal

WHAT IS THE BEST WAY TO WHAT IS THE BEST WAY TO LOSE WEIGHT?LOSE WEIGHT?

Decrease energy in and/or increase energy Decrease energy in and/or increase energy out, which means lower calorie intake and out, which means lower calorie intake and

increase activity level.increase activity level.

BUT, IT IS STILL IMPORTANT TO MAINTAIN BUT, IT IS STILL IMPORTANT TO MAINTAIN A BALANCED DIET THAT INCLUDES ALL A BALANCED DIET THAT INCLUDES ALL

NECESSARY NUTRIENTS!NECESSARY NUTRIENTS!

FACTFACT

Over the last 20 years, rate of obesity in Over the last 20 years, rate of obesity in teens has tripled to over 16%.teens has tripled to over 16%.

~Center for Science in the Public Interest, 2005~Center for Science in the Public Interest, 2005

Cyclic DietingCyclic Dieting

• Also known as “yo-yo” dietingAlso known as “yo-yo” dieting

• Recent research shows that the risk of Recent research shows that the risk of trying to lose weight over and over again is trying to lose weight over and over again is a mytha myth

• It is actually better for your weight to be It is actually better for your weight to be down half of the time than never at alldown half of the time than never at all

Adolescent NutritionAdolescent Nutrition

FACTFACT

Only 2% of teens with a healthy weight eat a Only 2% of teens with a healthy weight eat a nutritious diet as defined by the USDA.nutritious diet as defined by the USDA.


Adolescent NutritionAdolescent Nutrition

• ““Adolescence is a time of rapid physiologic, psychological, Adolescence is a time of rapid physiologic, psychological, and social development influencing nutrient needs as well as and social development influencing nutrient needs as well as the individual’s ability to supply those needs. Disruptions in the individual’s ability to supply those needs. Disruptions in the balance between nutrient requirements and intake during the balance between nutrient requirements and intake during adolescence impact on such major health problems as adolescence impact on such major health problems as atherosclerosis, hypertension, obesity, anorexia nervosa, atherosclerosis, hypertension, obesity, anorexia nervosa, bulimia nervosa, and birth of suboptimal-weight infants. bulimia nervosa, and birth of suboptimal-weight infants. Dietary and exercise habits formed as the adolescent Dietary and exercise habits formed as the adolescent achieves increased independence have the potential to achieves increased independence have the potential to enhance or undermine health throughout life. Dietary enhance or undermine health throughout life. Dietary indiscretion as another form of risk-taking behavior is a new indiscretion as another form of risk-taking behavior is a new concept worthy of scientific inquiry.”concept worthy of scientific inquiry.”

~ Marc. S. Jacobson, MD, LIJ, Schneider, Children’s Hospital~ Marc. S. Jacobson, MD, LIJ, Schneider, Children’s Hospital

Reasons for Nutritional Deficiencies Reasons for Nutritional Deficiencies in Teensin Teens

• More responsibilities, ex. part-time jobMore responsibilities, ex. part-time job• More freedom, ex. license, datingMore freedom, ex. license, dating• Increase in sedentary activities, ex. video games, IMIncrease in sedentary activities, ex. video games, IM• Changes in traditional family (more responsible for own Changes in traditional family (more responsible for own

meals)meals)• Social pressures, ex. being thin, rebelling against Social pressures, ex. being thin, rebelling against

parents, showing athletic prowessparents, showing athletic prowess

ALL OF THESE CAN RESULT INALL OF THESE CAN RESULT INPOOR FOOD CHOICES!!POOR FOOD CHOICES!!

FACTFACT

Children receive over 30 marketing Children receive over 30 marketing messages for food EVERY DAY.messages for food EVERY DAY.


Reasons Teens Have Increased Reasons Teens Have Increased Nutritional RequirementsNutritional Requirements

• Proper nutrition improves behavior, school Proper nutrition improves behavior, school performance, and cognitive development!performance, and cognitive development!

• Proper nutrition increases participation in Proper nutrition increases participation in school activities!school activities!

• Proper nutrition now will lead to good eating Proper nutrition now will lead to good eating habits later in life!habits later in life!


• Adolescent growth spurts (peaks at Adolescent growth spurts (peaks at puberty)puberty)

• Begins at 10/11 years old in girls, done at 15 Begins at 10/11 years old in girls, done at 15 • Begins at 12/13 years old in boys, done at 19Begins at 12/13 years old in boys, done at 19

• Increase in height, so increase in skeletal Increase in height, so increase in skeletal mass (gain 45% of adult skeletal mass)mass (gain 45% of adult skeletal mass)

• Menstruation in femalesMenstruation in females


• Lean body mass doubles in malesLean body mass doubles in males

• Body fat content doubles in females Body fat content doubles in females (from 10 to 20%)(from 10 to 20%)

• Hormonal changes affecting different Hormonal changes affecting different organs, including the BRAINorgans, including the BRAIN

• Sexual maturationSexual maturation

Increased Nutrient Requirements Increased Nutrient Requirements in Adolescentsin Adolescents

• Increased calories: for girls 2,200 Cal/day and Increased calories: for girls 2,200 Cal/day and for boys 2,500+ Cal/day for boys 2,500+ Cal/day

• Fiber: 30-40 grams/dayFiber: 30-40 grams/day• Needed for normal bowel function, preventing cancer, and Needed for normal bowel function, preventing cancer, and

coronary artery diseasecoronary artery disease

• Vitamins A, C, EVitamins A, C, E• Vitamin A is needed for visionVitamin A is needed for vision• Vitamin C used quickly under emotional and physical stressVitamin C used quickly under emotional and physical stress• Vitamin E is an antioxidantVitamin E is an antioxidant

Increased Nutrient Requirements Increased Nutrient Requirements in Adolescentsin Adolescents

• Protein: 50-60 grams/dayProtein: 50-60 grams/day• Calcium: 1,300-1,500 mg/day Calcium: 1,300-1,500 mg/day • Iron: for girls 15 mg/day and for boys 12 mg/dayIron: for girls 15 mg/day and for boys 12 mg/day

• Necessary for transporting oxygenNecessary for transporting oxygen• Needed to make red blood cells (menstruation)Needed to make red blood cells (menstruation)

• Other minerals: zinc, phosphorous, magnesiumOther minerals: zinc, phosphorous, magnesium• Zinc is necessary for protein formation and Zinc is necessary for protein formation and

sexual maturationsexual maturation

Nutritional Deficiencies in AdolescentsNutritional Deficiencies in Adolescents

• Ca (only 600-800 mg/day consumed)Ca (only 600-800 mg/day consumed)• Fe (iron-deficient anemia affects 2-10% of Fe (iron-deficient anemia affects 2-10% of

this age group)this age group)• Excess sodiumExcess sodium• Dietary fat >33% of caloriesDietary fat >33% of calories• French fries >25% of all vegetablesFrench fries >25% of all vegetables• Simple sugars exceed complex carbsSimple sugars exceed complex carbs• Fiber <50% of RDAFiber <50% of RDA

FACTFACT

60% of overweight 5 to 10 year olds have 60% of overweight 5 to 10 year olds have at least 1 risk factor for heart disease.at least 1 risk factor for heart disease.

Examples: increased BP and/or insulin levelsExamples: increased BP and/or insulin levels

**This number is equal to approximately 25% **This number is equal to approximately 25% of all 5 to 10 year olds.**of all 5 to 10 year olds.**

~~Guidelines for Adolescent Nutrition ServicesGuidelines for Adolescent Nutrition Services, 2005 - J. Stang and M. Story, Editors., 2005 - J. Stang and M. Story, Editors.

FACTFACTTOP TEN SOURCES OF ENERGY FOR TEENSTOP TEN SOURCES OF ENERGY FOR TEENS

1)1) MILKMILK

2)2) BREADBREAD

3)3) CAKES/COOKIES/DONUTSCAKES/COOKIES/DONUTS

4)4) BEEFBEEF

5)5) CEREALCEREAL

6)6) SODASODA

7)7) CHEESECHEESE

8)8) CHIPSCHIPS

9)9) SUGARSUGAR

10)10) CHICKENCHICKEN~~Guidelines for Adolescent Nutrition ServicesGuidelines for Adolescent Nutrition Services, 2005 - J. Stang and M. Story, Editors., 2005 - J. Stang and M. Story, Editors.

FACTFACT

Sweeteners and added sugars provide Sweeteners and added sugars provide

over 20% of a teenager’sover 20% of a teenager’s

total calories per day.total calories per day.


FACTFACT

Almost 10% of teenagers calories Almost 10% of teenagers calories

come from soda.come from soda.


FACT: Teens who drink more than two cans FACT: Teens who drink more than two cans of soda per day demonstrate poor nutrition in of soda per day demonstrate poor nutrition in

many other areas.many other areas.

Nonconsumers 0.1-12.9 oz/d 13-25.9 oz/d >26 oz/d Energy (kcal) 1,984+/-121 2,149+/-113 2,312+/-120 2,604+/-135 Riboflavin (B2) 2.1 1.94 1.67 1.53 Folate 239 238 191 178 Vit C 98 101 62 53 Calcium 820 804 652 636 Vit A 3,590 3,876 2,878 2,579

Nutrient Intake by Level of Soft Drink ConsumptionNutrient Intake by Level of Soft Drink Consumption


FACTFACT

Less than 25% of boys and less than Less than 25% of boys and less than

50% of girls consume the 50% of girls consume the

recommended servings of fruit per recommended servings of fruit per

day.day.


Nutritional Problems of AdolescentsNutritional Problems of Adolescents

• Eating disorders (includes crash dieting)Eating disorders (includes crash dieting)

• Chronic disease – obesity, diabetes, heart Chronic disease – obesity, diabetes, heart

diseasedisease

• Delayed growthDelayed growth

• Delayed sexual maturationDelayed sexual maturation

Why?Why?

Dietary Sources of Nutrients Needed by AdolescentsDietary Sources of Nutrients Needed by Adolescents

• Vitamin A:Vitamin A:– Tomatoes, winter squash, Tomatoes, winter squash,

cantaloupe, carrots, cantaloupe, carrots, spinach, broccoli, sweet spinach, broccoli, sweet potatopotato

• Vitamin B6:Vitamin B6:– Soybeans, bananas, meat, Soybeans, bananas, meat,

fish, beans, nuts, whole fish, beans, nuts, whole grainsgrains

• Vitamin E: Vitamin E: – Oils (wheat germ, Oils (wheat germ,

sunflower, safflower, corn), sunflower, safflower, corn), almonds, peanutsalmonds, peanuts

• Vitamin D: Vitamin D: – Sunlight, fortified milkSunlight, fortified milk

• Vitamin C:Vitamin C:– Peppers, broccoli, citrus Peppers, broccoli, citrus

fruits, strawberries, melons, fruits, strawberries, melons, tomatoes, cabbage, green tomatoes, cabbage, green leafy vegetables, papaya, leafy vegetables, papaya, winter squashwinter squash

• Folic acidFolic acid::– Green leafy vegetables, Green leafy vegetables,

beans, asparagus, orange beans, asparagus, orange juicejuice

• Iron:Iron:– Fish, green vegetables, Fish, green vegetables,

nuts, iron-fortified cereals, nuts, iron-fortified cereals, raisins.raisins.

• Calcium:Calcium:– Dairy products, green leafy Dairy products, green leafy

vegetables, salmonvegetables, salmon • Zinc: Zinc:

– Red meat, oysters, Red meat, oysters, crabmeat, beans, whole crabmeat, beans, whole grainsgrains

• Magnesium:Magnesium:– Whole seeds, nuts, Whole seeds, nuts,

legumes, grainslegumes, grains• Fiber:Fiber:

– Peas, beans, whole grains, Peas, beans, whole grains, sweet potato, green leafy sweet potato, green leafy vegetablesvegetables

Easy Ways to Improve Your NutritionEasy Ways to Improve Your Nutrition• Try leaner versions of foods like dairy products and Try leaner versions of foods like dairy products and

meatsmeats• Eat smaller portions more frequentlyEat smaller portions more frequently• Vary your diet so you don’t get boredVary your diet so you don’t get bored• Don’t overeat foods with added sweetenersDon’t overeat foods with added sweeteners• Put color into your diet with fruits and vegetablesPut color into your diet with fruits and vegetables• Think ahead so that you have snacks available when Think ahead so that you have snacks available when

you need energyyou need energy• Replace soda/lemonade/sports drinks with fruit juiceReplace soda/lemonade/sports drinks with fruit juice• EAT BREAKFASTEAT BREAKFAST• Try whole grain or wheat bread instead of whiteTry whole grain or wheat bread instead of white• Drink water, it helps to fill you upDrink water, it helps to fill you up• START MOVING!START MOVING!

Nutrition and Metabolism

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