Introduction to Nutrition

Introduction Introduction to Nutritionto Nutrition

Chapter 1Chapter 1

ObjectivesObjectives• After reading Chapter 1, class activities

and discussion you will be able to– Define frequently used terms– Identify factors affecting food choices– Discuss six major nutrient classes– Describe Dietary Reference Intakes– Describe ABCD’s of diet planning principles

ObjectivesObjectives• After reading Chapter 1, class activities

and discussion you will be able to: – Distinguish energy density of foods– Distinguish food’s nutrient density – Identify the energy value of carbohydrate,

protein, and fat– Calculate the energy available from foods

Food ChoicesFood Choices

Factors Influencing What You EatFactors Influencing What You Eat

6

Factors Influencing What You EatFactors Influencing What You Eat

• The most important consideration when choosing something to eat is flavor!flavor!

7

Factors Influencing What You EatFactors Influencing What You Eat• Flavor

– Taste– Smell– Appearance– Temperature– Texture

• Other Factors– Cost– Convenience– Availability– Familiarity– Nutritional Value

How Taste Influences What You How Taste Influences What You EatEato Flavor of food is

recognized by theo Sense of tasteo Sense of Smell

o Flavorous chemicals must be dissolved in water before they can be tasted

o Dry mouth prevents adequate tasting

How Taste Influences What You How Taste Influences What You EatEato 10,000 taste buds; 4 main

types:o Sweet, Sour, Salty, Bittero Umami, Piquant

o 50-150 receptor cells per taste bud

o 1-2 weeks cell lifeo Each receptor cell reflects

all flavors but more sensitive to one

How Taste Influences What You How Taste Influences What You EatEat

o Origins of different tastes:o Sweet = Saccharin of sugaro Sour = Acido Salty = Salt, sodium chlorideo Bitter = Alkaloidso Umami, Piquant

11

Factors Influencing What You EatFactors Influencing What You Eat

• Demographics– Age– Gender– Educational

level– Income

12

Factors Influencing What You EatFactors Influencing What You Eat

• Social and Emotional Influences– Social status– Peer pressure– Emotional status– Food associations

13

Factors Influencing What You EatFactors Influencing What You Eat• Food Industry and the

Media– Food industry

– Food advertising– Food portrayal in

media– Reporting of

nutrition/health studies

14

Factors Influencing What You EatFactors Influencing What You Eat

• Environmental Concerns– Use of synthetic fertilizers

and pesticides– Wastefulness of fattening

up livestock/poultry

15

Factors Influencing What You Eat

• Health– Health status– Desire to improve

health/appearance– Nutrition knowledge and attitudes

What is Nutrition?

17

What is What is Nutrition?Nutrition?Nutrition is a science that:studies nutrients and other substances in foods

and in the body and how these nutrients relate to health and disease, and

explores why you choose particular foods and the type of diet you eat.

science of foods and nutrients

1 q.p. 9

NutrientsNutrients Nourishing

substances in food that provide energy and promote the growth and maintenance of your body.

p. 96. i

NutrientsNutrients• Nutrient composition of foods and

the human body are similar• Nutrient composition of foods

–Six classes of nutrients –Nonnutrients

• Example: Phytochemicals • 7. j

» p. 222

FoodsFoods• Derived from plant or animal

sources• Provide energy and nutrients

–Used by the body for maintenance, growth, and repair

–2 p

DietDiet • The foods one consumes affects

• The quality of life now • The risk of chronic diseases later

– UC San Francisco study-Aug 2010» 3258 subjects 18-30 y.o.» Studied for 20 years » 5 ½ x more likely to develop CHD

• 3 op. 10

Body CompositionBody Composition

60%

Nutrients in the BodyNutrients in the Body • Nutrient composition of the body

–Water = 60%–Fat = 13-31%

• Male = 13 -21%• Female = 23 -31%

–Carbohydrate, Protein, Vitamins, Minerals, Other = 9 – 27%

Nutrients in the BodyNutrients in the Body• Example: 150# body

– Water = 90#– Fat = 20 -45#– Carbohydrate, Protein, Major Minerals

= 15 -40#– Vitamin, Minor Minerals = < 1#

More About NutrientsMore About Nutrients• Energy defined

– Capacity to do work– 5 h

• Nutrient defined– Growth– Maintenance

27

Carbohydrates 4 kcal/gram

Lipids 9 kcal/gram

Protein 4 kcal/gram

p. 1217. a

28

Functions of NutrientsFunctions of NutrientsNutrients Provide

EnergyPromote

GrowthMaintenance

Regulate Body

Processes

Carbohydrates X

Lipids X X XProteins X X XVitamins X X

Minerals X X

Water X X

More About NutrientsMore About Nutrients• Chemical composition of nutrients

– Inorganic vs. Organic nutrients• Inorganic = contain NO carbon• Organic = contain carbon• Organic literally meaning “alive”

• 9 l• 10 m

More About More About NutrientsNutrients

• Inorganic nutrients– Minerals -Water

• Organic nutrients– Carbohydrates -Lipids– Proteins -Vitamins

The NutrientsThe Nutrients

NutrientsNutrients• Essential nutrients (approx. 40)

– 11 f• Macronutrients -12. g

– Carbohydrates– Proteins– Fats

• Micronutrients– Vitamins– Minerals

33

Essential NutrientsEssential Nutrients

Nutrients that either cannot be made in the body or cannot be made in the quantities needed by the body; therefore, we must obtain them through food.

EXAMPLESGlucose, vitamins, minerals, water, some lipids, and some parts of protein.

Six Classes of Six Classes of Nutrients Nutrients

35

Classes of Nutrients - OverviewClasses of Nutrients - Overview

• CarbohydratesCarbohydrates

• Lipids (fats)Lipids (fats)

• ProteinsProteins

• VitaminsVitamins

• MineralsMinerals

• WaterWater

36

CarbohydratesCarbohydrates• A large class of

nutrients, including:– Sugars– Starch– Fibersthat function as thebody’s primarysource of energy.

LipidsLipids• A group of fatty

substances, including triglycerides and cholesterol, that are not soluble in water and provide a rich source of energy and structure to cells.

38

ProteinProtein• Major structural parts

of the body’s cells that are made of nitrogen-containing amino acids assembled in chains.

• Particularly rich in animal foods.

• Present in many plant foods.

39

Vitamins and MineralsVitamins and Minerals• Vitamins: Noncaloric,

organic nutrients found in a wide variety of foods that are essential to:

– regulate body processes.

– maintain the body.– allow growth and

reproduction.– 15. c

• Minerals: Noncaloric, inorganic nutrients found in a wide variety of foods that are essential to:– regulate body processes.– maintain the body.– allow growth and

reproduction.– 16. b

40

WaterWater• Inorganic nutrient that

plays a vital role in all bodily processes and makes up just over half of the body’s weight.

41

Food FactsFood Facts• Most foods provide a mix

of nutrients.

• Food contains more than just nutrients – food may contain colorings, flavorings, phytochemicals, caffeine, and other substances.

Nutrient Nutrient DensityDensity

43

Nutrient DensityNutrient Density• All foods were not created equal in terms of the kcalories

and nutrients they provide.• Nutrient density: A measure of the nutrients provided in a

food per kcalorie of the food.• Empty-kcalorie foods: Foods that provide few/no nutrients for the number of kcalories they contain. 8. k p. 13-14

Nutrient DensityNutrient Density• Which food item

has the greatest nutrient density?

• “NuVal”?

45

Nutrient Density Comparison: % DRI intakes for selected nutrients.

p. 14

Energy DensityEnergy Density• Energy Density

–A measure of the energy a food provides relative to the amount of food (kcal per gram) • “empty calories”• 14. d

Energy DensityEnergy Density

Nutritious DietNutritious Diet

49

Characteristics of A Nutritious DietCharacteristics of A Nutritious Diet

• Adequate• Balanced• Moderate• Varied

p. 16

Diet Planning PrinciplesDiet Planning Principles• AAdequacy-amounts sufficient to

maintain health• BBalance-foods proportionate to each

other and body’s needs• CControl-Kcalorie (energy)-food

energy intake management• Moderation: Enough but not too much

Diet Planning PrinciplesDiet Planning Principles• DDensity: Caloric/Nutrient

–Empty-kilocalorie foods–Nutrient dense foods

• VARIETY!VARIETY!– Eating a wide selection– Whole foods

52

Dietary Reference Intake (DRI)Dietary Reference Intake (DRI)

• Dietary Reference Intake: a set of values that serve as standards for nutrient intakes for healthy persons.

53

Dietary Reference Intakes (DRI)Dietary Reference Intakes (DRI)

• Recommended Dietary AllowanceRecommended Dietary Allowance (RDA)(RDA)Intake value sufficient to meet Intake value sufficient to meet nutrient requirements of 97-98% of nutrient requirements of 97-98% of all healthy individuals in a group.all healthy individuals in a group.

• Adequate Intake (AI)Intake value used when a RDA cannot be based on an EAR because there’s not enough scientific data.

54

Dietary Reference IntakesDietary Reference Intakes• Tolerable Upper Intake Level (UL)

Maximum intake level above which toxicity would increase. • Estimated Average Requirement (EAR)

Intake value estimated to meet requirement of half the healthy individuals in a group.

• Estimated Energy Requirement (EER)The dietary energy intake measured in kcalories that is needed to maintain energy balance in a healthy adult.

• Acceptable Macronutrient Distribution Ranges (AMDR)A range of intakes for a particular nutrient that is associated with reduced risk of chronic disease while providing adequate intake.– Adults: 45-65% of Kcal from carbohydrates– 25-35 % from fat– 10-36% from protein

p. 17

55

Dietary Reference IntakesDietary Reference Intakes

• RDA and AI – useful in planning diets for individuals

• EAR - useful in planning diets for groups

DRIDRI

DRIDRI

How does the How does the body get its body get its nutrients?nutrients?

59

Digestion, Absorption, & MetabolismDigestion, Absorption, & Metabolism

• Digestion: Process by which food is broken down into its components in the gastrointestinal tract with the help of digestive enzymes.

• Absorption: The passage of digested nutrients through the walls of the intestines or stomach into the blood or lymph, where they are transported to the cells.

• Metabolism: All the chemical processes by which nutrients are used to support life, includes anabolism and catabolism.

60

““Digestibility”Digestibility”• Digestibility: The amount of a food or nutrient that is

available for absorption after digestion.• NOT a set of symptoms associated with eating or

digestion.– Reflux symptoms

• “After taste”• Belching, burping• “Heartburn”• Regurgitation

– Intestinal gas formation– Upset stomach, “indigestion”– Nausea, vomiting, diarrhea

61

Digestion of a Sandwich

Digestion of a Sandwich

The Fate of a Piece of Pizza……..

• Using the last two slides as a guide, write down what would happen to a piece of pizza in each part of the body.

• Work with your group of colleagues if you would like.

• Let your instructor know when you are done.

More on FoodMore on Food

67

Food BasicsFood Basics1. Whole foods – fresh, unprocessed2. Fresh foods – raw, no preservatives3. Processed foods – procedure applied:

• Canning, freezing, dehydrating, milling4. Enriched foods – nutrients replaced5. Fortified foods – nutrients added

p. 26-29

More Food BasicsMore Food Basics

• Textured vegetable protein• Imitation foods (cheese, milk) • Food substitutes (egg)

Functional FoodFunctional Food• Functional foods

• Provide health benefits beyond their nutrient contributions

• Ex. Whole foods, fortified foods, modified foods (engineered, designer)

– Calcium fortified orange juice– Margarine containing plant sterols– 4-n

70

Organic FoodsOrganic Foods• Organic food is produced without using most:

– Conventional pesticides– Petroleum-based fertilizers or sewage sludge-based

fertilizers– Bioengineering– Ionizing radiation (irradiation)

• Organic farms must be inspected annually.• All organically-raised animals may not be given

hormones or antibiotics, and must have access to pasture.

71

Labeling of Organic FoodsLabeling of Organic Foods

Courtesy of USDA

ReviewReview

ObjectivesObjectives• After reading Chapter 1, class activities

and discussion you will be able to– Define frequently used terms– Identify factors affecting food choices– Discuss six major nutrient classes– Describe Dietary Reference Intakes– Describe ABCD’s of diet planning principles

ObjectivesObjectives• After reading Chapter 1, class activities

and discussion you will be able to: – Distinguish energy density of foods– Distinguish food’s nutrient density – Identify the energy value of carbohydrate,

protein, and fat– Calculate the energy available from foods