An Overview of

NutritionChapter #1

Nutrition in Your Life

Section #1.1

Section Introduction Believe it or not, you have probably eaten

at 20, 000 meals in your life. Without any conscious effort on your part, your body uses the nutrients from those foods to make all its components, fuel all its activities, and defend itself against diseases. How successfully your body handles these tasks depends, in part, on your food choices. Nutritious food choices support healthy bodies.

Nutrition in Your Life Nutrition:

The science of foods and the nutrients and other substances they contain, and of their actions within the body.

Foods: Products derived from plants or animals that can be

taken into the body to yield energy and nutrients for the maintenance of life and the growth and repair of tissues.

Diet: The foods and beverages a person eats and drinks.

Food Choices People decide what to eat, when to eat, and even

whether to eat in highly personal ways, often based on behavioral or social motives, including: Personal Preference Habit Ethnic Heritage or Tradition Social Interactions Availability, Convenience, and Economy Positive and Negative Associations Emotional Comfort Values Body Weight and Image Nutrition and Health Benefits

Functional Foods: Foods that provide health benefits beyond their nutrient

contributions.

The NutrientsSection #1.2

The Nutrients Nutrients:

Chemical substances obtained from food and used in the body to provide energy, structural materials, and regulating agents to support growth, maintenance, and repair of the body’s tissues.

Energy: The capacity to do work.

Nutrients in Foods and in the Body Composition of Foods:

Phytochemicals: Non-nutrient compounds found in plant-derived foods that have

biological activity in the body. Non-nutrients:

Compounds in foods that do not fit within the 6 classes of nutrients.

Composition of the Body Chemical Composition of Nutrients:

Inorganic: Not containing carbon or pertaining to living things.

Organic: A substance or molecule containing carbon-carbon bonds or

carbon-hydrogen bonds. Essential Nutrients:

Nutrients a person must obtain from food because the body cannot make them for itself in sufficient quantity to meet physiological needs.

Energy-Yielding Nutrients Energy-Yielding Nutrients:

The nutrients that break down to yield energy the body can use.

The Energy-Yield Nutrients: Carbohydrates Fats Proteins

In addition to providing energy, these nutrients also provide the raw materials for building the body’s tissues and regulating its many activities.

How Food Energy is Measured Energy Measured in kCalories

Calories: Units by which energy is measured.

The amount of energy a food provides depends on how much carbohydrate, fat, and protein it contains. Energy Density:

A measure of the energy a food provides relative to the amount of food.

When the body uses energy-yielding nutrients, the bonds between the nutrient’s atoms break causing them to release energy.

kCalorie Values of Energy NutrientsEnergy Nutrient kCalories (per gram)

Carbohydrate 4 kcal/ gram

Fat 9 kcal/ gram

Protein 4 kcal/ gram

How to Calculate Food Energy1. Multiply the number of grams of

carbohydrate by 4.2. Multiply the number of grams of protein by

4.3. Multiply the number of grams of fat by 9.4. Add the results from 1-3 together.5. Divide each amount of energy nutrients by

the total calories in the food.6. Multiply each by 100 to get the percentage.

Example: Calculating Food Energy 1 slice of bread with 1 Tbsp. of peanut

butter on it contains 16 grams carbohydrate, 7 grams of protein, and 9 grams of fat.

16 g x 4kcal/gram = 64 kcal

7 g x 4kcal/ gram = 28 kcal

9 g x 9kcal/ gram = 81 kcal

64 + 28 + 81 = 173 kcal

64 / 173 = .369 (.37) 37%

28 / 173 = .16 16%

81 / 173 = .468 (.47) 47%

The Vitamins Vitamins:

Organic, essential nutrients required in small amounts by the body for health.

There are 13 different vitamins, each with its own special role to play.

Vitamins can only function if they are intact.

The Minerals Minerals:

Inorganic elements which may be essential nutrients required in small amount by the body for health.

16 minerals are known to be essential in human nutrition.

Because minerals are inorganic, they are indestructible and do not need to be handled with special care.

Water Participates in metabolic reactions. Supplies the medium for transporting

vital materials to cells and waste products away from them.

The Science of Nutrition

Section #1.3

The Science of Nutrition Nutrition:

The study of the nutrients and other substances in foods and the body’s handling of them.

The foundation of nutrition depends on biology, biochemistry, and physiology.

The science of nutrition is growing as scientists apply knowledge gained from sequencing the human genome which is leading to nutritional genomics. Genome:

The full complement of genetic material in the chromosomes of a cell.

Nutritional Genomics: The science of how nutrients affect the activities of genes

and how genes affect the activities of nutrients.

Nutrition Research Researchers use the

scientific method to guide their work.

Hypothesis: An unproven statement

that tentatively explains the relationships between two or more variables.

Theory: A tentative explanation

that integrates many and diverse findings to further the understanding of a defined topic.

Observation & Question

Hypothesis & Prediction

Experiment

Results & Interpretations

Hypothesis Supported

Theory

Hypothesis Not Supported

New Observations & Questions

The Control Subjects:

The people or animals participating in a research project.

Subjects are typically divided into 2 groups: Experimental Group:

A group of individuals similar in all possible respects to the control group except for the treatment.

Control Group: A group of individuals similar in all possible respects to the

experimental group except for the treatment. Research participants get placed in either the control or

experimental group through randomization. Randomization:

A process of choosing the members of the experimental and control groups without bias.

Aspects of Nutrition Research Sample Size Placebos:

An inert, harmless medication given to provide comfort and hope; a sham treatment used in controlled research studies.

Placebo Effect: The result of expectations in the effectiveness of a medicine,

even medicine without pharmaceutical effects. Double Blind Experiment:

An experiment in which neither the subjects nor the researchers know which subjects are members of the experimental group and which are serving as control subjects, until after the experiment is over.

Blind Experiment: An experiment in which the subjects do not know whether they

are members of the experimental group or the control group.

Aspects of Nutrition Research (continued) Correlations and Causes:

Correlation: The simultaneous increase, decrease, or change in two

variables. Variables:

Factors that change. Positive Correlation:

Occurs only if both variables increase or decrease. Negative Correlation:

Occurs only if one variable increases and the other decreases. Replication:

Repeating an experiment and getting the same results. Peer-Review:

A process in which a panel of scientists rigorously evaluate a research study to assure that the scientific method was followed.

Research vs. Rumors Validity:

Having the quality of being founded on fact or evidence. To determine if a claim is actual research or a rumor,

ask yourself the following: Who participated in the study, and how were they

selected? Were the control and experimental groups similar? Was the sample size large enough to rule out chance

variation? Was a placebo effectively administered? Was the experiment double blind? Were the variables selected appropriately and measured

accurately? Do the data support the conclusions?

Dietary Reference

Intakes (DRI)Section #1.3

Dietary Reference Intakes (DRI) Dietary References Intakes (DRIs):

A set of nutrient intake values for healthy people in the United States and Canada.

DRIs include: Estimated Average Requirements (EAR) Recommended Dietary Allowances (RDA) Adequate Intakes (AI) Tolerable Upper Intake Levels (UL)

Establishing Nutrient Recommendations Estimated Average Requirements (EAR):

The average daily amount of a nutrient that will maintain a specific biochemical or physiological function in half the healthy people of a given age and gender group.

Recommended Dietary Allowances (RDA): The average daily amount of a nutrient considered adequate

to meet the known nutrient needs of practically all healthy people.

Adequate Intakes (AI): The average daily amount of a nutrient that appears

sufficient to maintain a specified criterion. Tolerable Upper Intake Levels (UL):

The maximum daily amount of a nutrient that appears safe for most healthy people and beyond which there is an increased risk of adverse health effects.

Establishing Energy Requirements Estimated Energy Requirement (EER):

The average dietary energy intake that maintains energy balance and good health in a person of a given age, gender, weight, height, and level of physical activity.

Acceptable Macronutrient Distribution Ranges (AMDR): Ranges of intakes for the energy nutrients that provide

adequate energy and nutrients and reduce the risk of chronic diseases.

AMDRs: Carbohydrate: 45% to 65% Lipid: 20% to 35% Protein: 10% to 35%

Using Nutrient Recommendations Adequate energy and nutrient intakes apply to

healthy people only. Recommendations are not minimum

requirements, or optimal intakes for all individuals.

Most nutrient goals are intended to be met through diets composed of a variety of foods.

Recommendations apply to average daily intakes.

Each DRI category serves a unique purpose.

Nutrition AssessmentSection #1.4

Nutrition Assessment When a person doesn’t get enough or gets too

much of a nutrient or energy over an extended period of time, that person can start to show signs of malnutrition, undernutrition, or overnutrition. Malnutrition:

Any conditions caused by excess or deficient food energy or nutrient intake or by an imbalance of nutrients.

Undernutrition: Deficient energy or nutrients.

Overnutrition: Excess energy or nutrients.

Nutrition Assessment of Individuals To prepare a nutrition assessment, a registered

dietician or other trained healthy care professional uses: Historical Information Anthropometric Data

Anthropometric: Relating to measurement of the physical characteristics of

the body, such as height and weight. Physical Examinations Laboratory Tests

Nutrition Assessment: A comprehensive analysis of a person’s nutrition

status that uses health, socioeconomic, drug, and diet histories.

Nutrition Assessment of Populations To assess a population’s nutrition status,

researchers conduct surveys using techniques similar to those used on individuals.

The data collected are then used by various agencies for numerous purposes, including the development of national health goals. Healthy People:

A national public health initiative under the jurisdiction of the U.S. Department of Health and Human Services that identifies the most significant preventable threats to health and focuses efforts toward eliminating them.

The data is collected through national nutrition surveys.

Diet and HealthSection #1.5

Diet and Health Diet has always played a vital role in

supporting health. Recently, nutrition research has focused

on chronic diseases associated with energy and nutrient excesses. Chronic Disease:

Diseases characterized by a slow progression and long duration.

Risk Factors for Chronic Diseases Risk Factor:

A condition or behavior associated with an elevated frequency of a disease but not proved to be causal.

Risk Factor % of Death

s

Tobacco 20%

Poor Diet/ Inactivity

14%

Alcohol 6%

Microbial Agents 4%

Pollutants/ Toxins 3%

Firearms 2%

Sexual Behavior 1%

Motor Vehicles 1%

Illicit Drugs 1%

Bibliography “Understanding Nutrition, 10th Ed.”

Rolfes, S.R., Whitney, E. (2005). Thomson- Wadsworth; Belmont, CA.