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Chapter 1

Introduction to Nutrition

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Factors Influencing What You Eat

Flavor Taste Smell Appearance Texture Temperature

Other Aspects of Food Cost Convenience Availability Familiarity Nutrition

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The most important consideration when choosing something to eat is flavor.

The most important consideration when choosing something to eat is flavor. (Courtesy of PhotoDisc/Getty Images)

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Factors Influencing What You Eat

Demographics Age Gender Educational level Income

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Factors Influencing What You Eat

Culture and Religion Traditional foods Special

events/celebrations Religious

foods/practices

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Factors Influencing What You Eat

Health Health status Desire to improve

health/appearance Nutrition knowledge

and attitudes

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Factors Influencing What You Eat

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

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Factors Influencing What You Eat

Food Industry and the Media Food industry

Food advertising Food portrayal in

media Reporting of

nutrition/health studies

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Factors Influencing What You Eat

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

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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.

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Nutrients are:

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

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Kilocalories

A measure of the energy in food. 1 kilocalorie raises the temperature of 1

kilogram of water 1 degree Celsius. Also called a Calorie. Abbreviated as kcalorie or kcal. When you hear “calorie,” it is really a

kilocalorie.

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The number of kilocalories you need is based on: Basal metabolism (about 2/3 of total energy

needs for individuals who are not very active)

Physical activity

Thermic effect or specific dynamic action of foods (5 to 10% of total energy needs)

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BMR depends on factors such as:

Gender Age Growth Height Temperature Fever and stress Exercise Smoking and caffeine Sleep

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Classes of Nutrients - Overview

Carbohydrates

Lipids (fats)

Proteins

Vitamins

Minerals

Water

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Carbohydrates A large class of

nutrients, including: Sugars Starch Fibersthat function as the

body’s primary source of

energy.

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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.

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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.

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Vitamins 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.

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.

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Water

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

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Functions of Nutrients

Nutrients Provide Energy Promote Growth and Maintenance

Regulate Body Processes

Carbohydrates X

Lipids X X X

Proteins X X X

Vitamins X X

Minerals X X

Water X X

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Food Facts

Most foods provide a mix of nutrients.

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

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Carbohydrates 4 kcal/gram

Lipids 9 kcal/gram

Protein 4 kcal/gram

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More Vocabulary

Micronutrients Macronutrients

Organic nutrients Inorganic nutrients

Carbohydrates Lipids Proteins Vitamins Minerals Water

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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.

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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.

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Nutrient Density Comparison: % DRI intakes for selected nutrients.

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Characteristics of A Nutritious Diet

Adequate Balanced Moderate Varied

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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.

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.

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Dietary Reference Intakes

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, 20-35% from fat,

and 10 to 35% from protein.

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Dietary Reference Intakes

RDA and AI – useful in planning diets for individuals

EAR - useful in planning diets for groups

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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.

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Food Basics1. Whole foods

2. Fresh foods

3. Organic foods

4. Processed foods

5. Enriched foods

6. Fortified foods

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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.

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Labeling of Organic Foods

Courtesy of USDA

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Copyright ©2007 John Wiley & Sons, Inc.