Introduction to Nutrition Chapter 1

Transcript Introduction to Nutrition Chapter 1

Introduction to Nutrition

Chapter 1

Objectives

• – – – – – 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

Objectives

• 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 Choices

Factors Influencing What You Eat

• The most important consideration when choosing something to eat is flavor! 6

Factors Influencing What You Eat

• Flavor – Taste – Smell – Appearance – Temperature – Texture • Other Factors – Cost – Convenience – Availability – Familiarity – Nutritional Value 7

How Taste Influences What You Eat

o Flavor of food is recognized by the o Sense of taste o 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 Eat

o 10,000 taste buds; 4 main types: o Sweet, Sour, Salty, Bitter o Umami, Piquant o 50-150 receptor cells per taste bud o 1-2 weeks cell life o Each receptor cell reflects all flavors but more sensitive to one

How Taste Influences What You Eat

o Origins of different tastes: o Sweet = Saccharin of sugar o Sour = Acid o Salty = Salt, sodium chloride o Bitter = Alkaloids o Umami, Piquant

Factors Influencing What You Eat

• Demographics – Age – Gender – Educational level – Income 11

Factors Influencing What You Eat

• Social and Emotional Influences – Social status – Peer pressure – Emotional status – Food associations 12

Factors Influencing What You Eat

• Food Industry and the Media – Food industry – Food advertising – Food portrayal in media – Reporting of nutrition/health studies 13

Factors Influencing What You Eat

• Environmental Concerns – Use of synthetic fertilizers and pesticides – Wastefulness of fattening up livestock/poultry 14

Factors Influencing What You Eat • Health – Health status – Desire to improve health/appearance – Nutrition knowledge and attitudes 15

What is 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 17

Nutrients

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

6. i p. 9

Nutrients

• • 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

Foods

• Derived from plant or animal sources • Provide energy and nutrients – Used by the body for maintenance, growth, and repair – 2 p

Diet

• 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 o p. 10

60%

Body Composition

Nutrients 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 Body

• Example: 150# body – Water = 90# – Fat = 20 -45# – Carbohydrate, Protein, Major Minerals = 15 -40# – Vitamin, Minor Minerals = < 1#

More About Nutrients

• Energy defined – – Capacity to do work 5 h • Nutrient defined – – Growth Maintenance

Carbohydrates Lipids Protein 4 kcal/gram 9 kcal/gram 4 kcal/gram p. 12 17. a 27

Functions of Nutrients

Nutrients Provide Energy Promote Growth Maintenance Regulate Body Processes Carbohydrates Lipids Proteins Vitamins Minerals Water X X X X X X X X X X X X X

More 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 Nutrients

• Inorganic nutrients – Minerals -Water • Organic nutrients – – Carbohydrates -Lipids Proteins -Vitamins

The Nutrients

Nutrients

• • • Essential nutrients (approx. 40) – 11 f Macronutrients 12. g – – – Carbohydrates Proteins Fats Micronutrients – Vitamins – Minerals

Essential 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.

EXAMPLES Glucose, vitamins, minerals, water, some lipids, and some parts of protein.

Six Classes of Nutrients

Classes of Nutrients - Overview

•

Carbohydrates

•

Vitamins

•

Lipids (fats)

•

Proteins

•

Minerals

•

Water

Carbohydrates

• A large class of nutrients, including: –

Sugars

–

Starch

–

Fibers

that function as the body’s primary source of energy. 36

Lipids

• 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.

Protein

• • • 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.

Vitamins and Minerals

• Vitamins to: : Noncaloric, organic nutrients found in a wide variety of foods that are essential – – – – 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 39

Water

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

Food 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 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 43

Nutrient Density

• Which food item has the greatest nutrient density?

• “NuVal”?

Nutrient Density Comparison: % DRI intakes for selected nutrients.

p. 14 45

Energy 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 Density

Nutritious Diet

Characteristics of A Nutritious Diet

• Adequate • Balanced • Moderate • Varied p. 16 49

Diet Planning Principles

• • •

dequacy-amounts sufficient to maintain health

alance-foods proportionate to each other and body ’ s needs

ontrol-Kcalorie (energy)-food energy intake management •

Moderation

: Enough but not too much

Diet Planning Principles

•

ensity: Caloric/Nutrient – Empty-kilocalorie foods – Nutrient dense foods •

VARIETY!

– – Eating a wide selection Whole foods

Dietary Reference Intake (DRI)

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

Dietary Reference Intakes (DRI)

• • Recommended Dietary Allowance (RDA) Intake value sufficient to meet nutrient requirements of 97-98% of 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.

Dietary 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 54

Dietary Reference Intakes

• RDA and AI – useful in planning diets for individuals • EAR - useful in planning diets for groups 55

DRI

How does the body get its nutrients?

Digestion, 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. 59

“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 60

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.

Food Basics

1. Whole foods – fresh, unprocessed 2. Fresh foods – raw, no preservatives 3. Processed foods – procedure applied: • Canning, freezing, dehydrating, milling 4. Enriched foods – nutrients replaced 5. Fortified foods – nutrients added p. 26-29 67

More Food Basics

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

Functional 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

Organic 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.

Labeling of Organic Foods

Courtesy of USDA 71

Introduction to Nutrition Chapter 1

Transcript Introduction to Nutrition Chapter 1