Understanding Nutrition, 17e Chapter 1: An Overview of Nutrition

Understanding Nutrition, 17e: Chapter 1: An Overview of Nutrition

Introduction

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Learning Objectives (1 of 2)

By the end of this chapter, you should be able to:

  • 1.1 Describe how various factors influence personal food choices.

  • 1.2 Describe the essential nutrients required by the body.

  • 1.3 Explain the scientific method and how scientists use various types of research studies and methods to acquire nutrition information.

Learning Objectives (2 of 2)

By the end of this chapter, you should be able to:

  • 1.4 Explain the purposes of the various categories of the DRI.

  • 1.5 Describe the nutrition assessment methods used to detect energy and nutrient deficiencies and excesses.

  • 1.6 Identify the relationships between dietary factors and chronic diseases.

  • 1.7 Recognize nutrition misinformation.

Food Choices

  • Factors influencing Food Choices:

    • Preferences: Influenced by individual tastes, with strong attraction to sweet and savory flavors.

    • Taste Perception: The sensory evaluation of flavors in foods.

    • Habit: Regular patterns of food consumption.

    • Cultural Influences: Ethnic heritage and regional cuisines that shape dietary preferences.

    • Social Interactions: Meals shared with others can influence choices.

    • Marketing: Advertising impacts perceptions and choices.

    • Social Media Influence: Content shared on platforms can affect food trends.

    • Availability, Convenience, and Economy: Access to food options based on location and price.

    • Benefits of Home-Cooked Meals: Often healthier, more cost-effective, and customizable.

  • Additional Influencing Factors:

    • Positive and Negative Associations: Personal feelings connected to certain foods (comfort foods vs. aversions).

    • Emotions: Emotional states such as boredom, depression, anxiety, and stress can lead to different eating behaviors.

    • Values and Health Beliefs: Personal principles that guide dietary choices.

    • Nutrition Categories: Differentiation between whole foods, processed foods, and ultra-processed foods.

Discussion #1

  • Distinguish between processed foods and ultra-processed foods.

  • Examples of minimally processed foods: [To be discussed].

  • Examples of ultra-processed foods: [To be discussed].

  • Acceptable degree of processing in foods and potential health implications of processing levels.

The Nutrients

Nutrients in Foods and in the Body (1 of 2)

  • Nutrient Composition of Foods:

    • Carbohydrates

    • Proteins

    • Vitamins

    • Minerals

    • Lipids (Fat)

    • Water

Nutrients in Foods and in the Body (2 of 2)

  • Chemical Nature of Nutrients:

    • Minerals: Inorganic elements essential for numerous body functions.

    • Water: Creates an environment for bodily activities.

    • Essential Nutrients: Nutrients the body cannot synthesize and must obtain from food.

The Energy-Yielding Nutrients: Carbohydrate, Fat, and Protein

Energy Measurement

  • Energy is measured in kilocalories (kCalories).

  • Conversion: 1,000 calories equals 1 kcal.

  • Definition: One kcal is the amount of heat needed to raise the temperature of 1 kilogram of water by 1 degree Celsius (°C).

  • Energy derived from foods primarily comes from carbohydrates, fats, and proteins.

  • Energy Density: A measure of energy that food provides per unit of mass; fats provide more energy per gram than carbohydrates or proteins.

Energy in the Body

  • If the body does not use nutrients for immediate energy, it converts them into storage compounds (fat storage).

  • Other Roles of Energy-Yielding Nutrients:

    • Building Tissues: Such as muscles and skin.

    • Regulating Activities: Involves processes like digestion and energy metabolism.

Vitamins, Minerals, and Water

  • Vitamins: Organic compounds that facilitate energy release but do not provide energy themselves.

    • There are 13 vitamins required by the human body.

  • Minerals: The simplest nutrients, consisting of inorganic elements; 16 essential minerals identified for health.

  • Water: Serves as the medium for nearly all bodily activities.

Poll 1

  • Question: Which of the following facilitates the release of energy from carbohydrate, fat, and protein without actually providing energy?

    • a. Water

    • b. Minerals

    • c. Vitamins

    • d. Proteins

Case Study Activity

  • Task: Calculate the energy available from a bean burrito with cheese composed of 55 grams of carbohydrate, 15 grams of protein, and 12 grams of fat.

  • Determine the percentage of kcalories from each of the energy-yielding nutrients.

The Science of Nutrition

Overview of the Science of Nutrition

  • Nutrition relies on several foundational sciences including:

    • Biology

    • Biochemistry

    • Physiology

    • Chemistry

  • Growth in knowledge due to advancements like sequencing the human genome, leading to the field of nutritional genomics.

Conducting Research

  • Anecdotes: Individual experiences that do not provide reliable scientific evidence.

  • Scientific Method: A systematic process for conducting research.

    • Hypothesis: An educated guess that can be tested.

    • Controls: Experimental setup includes an experimental group and control group.

    • Randomization: Participants assigned to groups at random.

    • Sample Size: Refers to the number of subjects in a study; larger sizes improve validity.

    • Placebos: Treatments resembling the active treatment but are inert, often referred to as a sugar-pill.

    • Double-Blind Design: Neither the participants nor the researchers know who is receiving the treatment vs. the placebo.

Analyzing Research Findings

  • Understanding correlations and causes:

    • Positive Correlation: Indicates a relationship, not necessarily a desired outcome.

    • Negative Correlation: Indicates an inverse relationship.

    • No Correlation: No relationship exists between variables.

    • Drawing cautious conclusions requires accumulation of evidence.

Publishing Research

Part 1

  • Findings from research studies undergo peer review by other scientists to ensure the scientific method's integrity was maintained.

  • Validity of research is confirmed if evidence supports the conclusions, leading to possible publication in scientific journals.

  • Replications and reanalyses by other scientists are essential for confirming or disproving findings.

  • Review Articles: Published articles may provide a qualitative (systematic review) or a quantitative (meta-analysis) summary of the evidence, also requiring peer review.

Part 2

Table 1-3: Parts of a Typical Research Article

  • Abstract: Provides a brief overview of the article.

  • Introduction: States the study's purpose while reviewing relevant literature.

  • Methodology: Defines key terms, study design, subjects, and procedures.

  • Results: Reports findings; might include tables and figures that summarize data.

  • Discussion: Draws conclusions supported by data and addresses the initial purpose; raises new questions.

  • References: Demonstrates the investigator's knowledge with a comprehensive list of relevant studies.

Knowledge Check 1

  • Scenario: As ice cream sales increase, so do the number of shark attacks. What does this illustrate?

    • a. Conclusion

    • b. Causation

    • c. Placebo effect

    • d. Correlation

Dietary Reference Intakes (DRI)

Establishing Nutrient Recommendations

  • Dietary Reference Intakes (DRI): Set of nutrient intake values for healthy individuals in the U.S. and Canada. Includes:

    • Estimated Average Requirements (EAR)

    • Recommended Dietary Allowances (RDA)

    • Adequate Intakes (AI)

    • Tolerable Upper Intake Levels (UL)

    • Chronic Disease Risk Reduction Intakes (CDRR)

  • Nutrient Requirement: The lowest intake level of a nutrient to maintain a specified criterion of adequacy.

Comparison of EAR and RDA

  • Details comparing the definitions and usages of EAR vs. RDA are needed.

Inaccurate Versus Accurate View of Nutrient Intakes

  • This section delineates misunderstandings related to nutrient requirements.

Reflection 1

  1. The Estimated Average Requirement (EAR) meets the needs of ___% of the population.

  2. The Tolerable Upper Intake Levels (UL) protect against _.

  3. The ___ meets the needs of most healthy people in the population.

  4. The Adequate Intake (AI) is applicable when evidence is insufficient to establish the . This serves as a substitute for the .

  5. The first Chronic Disease Risk Reduction Intake (CDRR) was set for ___.

Establishing Energy Recommendations

  • Estimated Energy Requirement (EER): Indicates average dietary energy intake necessary to maintain energy balance and healthy body weight.

  • There is no established upper level for energy intake.

  • Acceptable Macronutrient Distribution Ranges (AMDR):

    • Carbohydrates: 45 to 65% of total kcalories

    • Fat: 20 to 35% of total kcalories

    • Protein: 10 to 35% of total kcalories

Reflection 2

  • Match the Acceptable Macronutrient Distribution Ranges (AMDR) with their respective macronutrients:

    • a. Carbohydrate

    • b. Protein

    • c. Fat

    • a. 20 to 35%

    • b. 45 to 65%

    • c. 10 to 35%

Using Nutrient Recommendations

  • DRI estimates pertain exclusively to healthy individuals; modifications are necessary for malnourished or medically affected persons.

  • Recommendations represent neither minimum requirements nor optimal intake levels.

  • DRI goals are intended to be met through a diverse diet.

  • Each DRI category has a unique purpose and application.

Energy Nutrient Contributions to Total Intake

  • A section is anticipated to explore how various nutrients contribute to overall energy intake.

Comparing Nutrient Recommendations

  • More than 80 nations have established nutrient standards aligning with those of the U.S.

  • Differences arise from varied interpretations of data and cultural dietary habits; groups such as the FAO and WHO also contribute to these recommendations.

Nutrition Assessment

Reasons for Nutrition Assessment

  • Importance of assessing nutrition to identify malnutrition caused by nutrient excesses or deficiencies.

  • Undernutrition: Defined as deficient energy or nutrient intake.

  • Overnutrition: Involves excess energy or nutrients.

  • Symptoms of malnutrition can mimic other diseases, including symptoms like diarrhea, skin rashes, and fatigue.

Nutrition Assessment of Individuals

  • Aspects considered in assessment:

    • Food/Nutrition-related history

    • Health status and socioeconomic status

    • Drug history

    • Diet history, which involves intake assessment over several days and examining portion sizes with computer analysis.

    • Anthropometric Measurements: Height and weight assessments track trends.

    • Physical Examinations and Laboratory tests, e.g., iron, glucose, cholesterol, LDL, HDL measurements.

Stages in the Development of a Nutrient Deficiency

  • Details on how nutrient deficiencies progress through various stages impacting physiological function and health.

Knowledge Check 2

  • Question: Which deficiency type occurs from causes other than low intake, like drug interactions affecting absorption?

    • a. Overt

    • b. Primary

    • c. Secondary

    • d. Subclinical

Nutrition Assessment of Populations

  • National nutrition surveys are conducted by various agencies focusing on food consumption types and amounts.

  • Surveys also collect personal data to address national health goals like those in the Healthy People Program.

Diet and Health

Leading Causes of Death in the United States (1 of 2)

  • Food's significant role in supporting health is highlighted by identifying five major causes of death associated with dietary factors:

    • Heart Disease: 167.2 deaths per 100,000 U.S. population

    • Cancers: 142.3 deaths

    • Unintentional Injuries: 64.0 deaths

    • COVID-19: 44.5 deaths

    • Strokes: 39.5 deaths

    • Dietary habits linked with above conditions make diet a modifiable risk factor.

Leading Causes of Death in the United States (2 of 2)

Table 1-4 summarizes other leading causes of death:

  • Chronic Lower Respiratory Diseases: 34.3 deaths

  • Alzheimer’s Disease: 28.9 deaths

  • Diabetes Mellitus: 24.1 deaths

  • Chronic Liver Disease/Cirrhosis: 13.8 deaths

  • Kidney Disease: 13.8 deaths

  • Diseases in bold exhibit direct dietary relationships.

Risk Factors for Chronic Diseases

  • Risk factors persist and cluster over time.

  • Prominent risk factors in the U.S. include:

    • Tobacco use

    • Diet and physical activity

    • Alcohol consumption

Discussion #2

  • Examination of unhealthy behaviors in the context of chronic diseases and discussions on students' actions for improving health behaviors.

Nutrition Misinformation

  • Evaluation of credibility in nutritional information sources and the potential for misinformation.

How to Determine if a Website is Reliable

  • Key Questions:

    • Who is responsible for the site?

    • When was the site last updated?

    • Where is the information sourced from?

    • Why is this site presenting this information?

    • Is the presented message reliable?

Credible Sources of Nutrition Information

  • Government Agencies: CDC, FDA

  • Volunteer Associations: ACS, AHA

  • Consumer Groups: American Council on Science and Health

  • Professional Organizations: AND, AMA

Knowledge Check 3

  • Question: Identify sources of reliable nutrition information. Check all that apply:

    • a. FDA website

    • b. American Heart Association pamphlet

    • c. Nutrition article in popular magazines

    • d. University or community college faculty member information

Summary

  1. Describe how various factors influence personal food choices.

  2. Describe essential nutrients required by the body.

  3. Explain the scientific method and research studies in nutrition.

  4. Explain the purposes of DRI categories.

  5. Describe methods in nutrition assessment for energy and nutrient status.

  6. Identify relationships between dietary factors and chronic diseases.

  7. Recognize nutrition misinformation.


Factors Influencing Personal Food Choices

  • Taste Preferences: The primary driver for food selection. Humans have an innate preference for high-fat and sweet foods, though bitter tastes are often naturally avoided as they may signal toxins/poisons.

  • Habit and Heritage: Routine often dictates choices (e.g., cereal every morning), while ethnic heritage connects individuals to specific ingredients and cooking methods.

  • Social Interactions: Food is a focal point of hospitality; people tend to eat more when dining with others.

  • Marketing and Media: Brand loyalty and social media trends (e.g., "superfoods") heavily influence consumer buying power.

  • Availability, Convenience, and Economy: The rise of "food deserts" restricts access to fresh produce, while the lower cost of energy-dense, nutrient-poor foods often leads to higher consumption in lower-income demographics.

  • Emotional Comfort: Binge eating may occur during stress or depression, whereas some individuals lose their appetite entirely during periods of anxiety.

  • Values and Beliefs: Religious restrictions (e.g., Halal, Kosher), environmental concerns (e.g., veganism), or political views (e.g., boycotting specific companies) guide food selection.

  • Processing Levels:

    • Whole Foods: Basic, unprocessed items like vegetables or grains.

    • Processed Foods: Foods subjected to any process (milling, cooking, freezing) that may alter nutritional properties.

    • Ultra-processed Foods: Foods made from substances typically used in food preparation but not consumed as food themselves (e.g., oils, fats, flours, sugars) and refined ingredients that contain little to no whole food (e.g., soft drinks, chips, frozen dinners).

The Nutrients: Solids, Liquids, and Energy

  • Chemical Composition: The human body is approximately 60%60\% water, with the remainder mostly fat and protein. Minimal amounts are minerals and carbohydrates.

  • Organic vs. Inorganic Nutrients:

    • Inorganic: Do not contain carbon (Minerals and Water).

    • Organic: Contain carbon (Carbohydrates, Lipids, Proteins, and Vitamins).

  • Essential Nutrients: Also called indispensable nutrients; the body cannot make them in sufficient quantities, so they must be obtained through the diet.

  • Energy-Yielding Nutrients:

    • Carbohydrates: Yield 4 kcal/g4 \text{ kcal/g}.

    • Proteins: Yield 4 kcal/g4 \text{ kcal/g}.

    • Lipids (Fats): Yield 9 kcal/g9 \text{ kcal/g}.

    • Alcohol: While not a nutrient, it contributes 7 kcal/g7 \text{ kcal/g} and can lead to fat storage.

  • The Energy-Yielding Role: When metabolized, the bonds between the atoms break, releasing energy which can be used immediately or stored as glycogen/adipose tissue.

Scientific Research and Nutrition

  • Types of Research Studies:

    • Epidemiological Studies: Research the incidence, distribution, and control of disease in a population. Includes cross-sectional, case-control, and cohort studies.

    • Experimental Studies: Test cause-and-effect relationships. Includes laboratory-based animal studies, in-vitro (cell) studies, and human intervention (clinical) trials.

  • Blinding and Controls:

    • Placebo: An inactive substance used to ensure that outcomes are due to the treatment, not expectations.

    • Double-Blind: Neither the subjects nor the researchers know who is in the experimental group to prevent researcher bias.

  • Correlation vs. Causation: A positive correlation (e.g., more Vitamin C, more colds) merely means variables change in the same direction; it does not prove one causes the other.

Dietary Reference Intakes (DRI)

  • ER (Estimated Average Requirement): The amount of a nutrient that will maintain a specific biochemical or physiological function in half (50%50\%) of the people of a given age and gender group.

  • RDA (Recommended Dietary Allowance): The average daily amount of a nutrient considered adequate to meet the known nutrient needs of practically all (98%98\%) healthy people. It is derived from the EAR.

  • AI (Adequate Intake): Used when an RDA cannot be determined; it is based on observed or experimentally determined approximations of nutrient intake by a group of healthy people.

  • UL (Tolerable Upper Intake Level): 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.

  • Acceptable Macronutrient Distribution Ranges (AMDR):

    • Carbohydrates: 45−65%45-65\% of total kcalories.

    • Fat: 20−35%20-35\% of total kcalories.

    • Protein: 10−35%10-35\% of total kcalories.

Nutrition Assessment

  • Malnutrition: Includes both undernutrition (deficiency) and overnutrition (excess).

  • Assessment Tools:

    • Anthropometric: Measures of physical characteristics like height, weight, and waist circumference.

    • Biochemical: Laboratory tests of blood or urine to detect internal physiological changes.

    • Clinical: Physical examination of hair, skin, eyes, tongue, or fingernails to detect overt symptoms.

    • Historical: Medical history (health status), drug history (medications), and diet history (24-hour recall or food frequency questionnaires).

  • Stages of Deficiency:

    • Primary Deficiency: Caused by inadequate diet.

    • Secondary Deficiency: Resulting from some other condition (e.g., malabsorption or drug interaction).

    • Subclinical Deficiency: A deficiency in the early stages, before outward signs have appeared.

Diet and Chronic Diseases

  • Chronic Diseases: Slow progression, long duration, and include heart disease, diabetes, and cancers.

  • Risk Factors: Factors that increase the likelihood of developing a disease.

    • Modifiable: Diet, physical activity, tobacco use, alcohol consumption.

    • Non-modifiable: Genetics, age, gender.

  • Interdependence: Risk factors usually cluster; for example, obesity often correlates with physical inactivity and poor dietary choices.