1. An Overview of Nutrition
Chapter 1
An Overview of Nutrition

2. Chapter Objectives
Identify the six classes of nutrients and determine which are energy-yielding nutrients.
List four factors that affect our food choices.
Explain why meeting nutrient needs by eating a well-balanced diet is a healthier choice than relying on supplements.
Describe the steps of the scientific method.
Discuss the three different types of research that scientists can use to test their hypothesis.
List several factors to consider when obtaining nutrition information on the internet.

3. Overview of Nutrition Nutrition Foods Diet
Science of foods and the substances they contain, their actions within the body
Foods
from plants or animal sources
Provide energy and nutrients
Used by the body for maintenance, growth, and repair
Diet
The foods one consumes.
The quality of which affects the risk of chronic diseases

4. What Drives Our Food Choices?
We choose foods for many other reasons beyond the basic need to obtain nutrients:
Taste
Ethnic heritage or tradition
Social interactions
Advertising
Availability, Convenience, and Economy
Habits
Emotional Comfort
Body Weight and image
Nutrition and Health Benefits

5. The Nutrients We need to eat and drink to obtain:
Nutrients: chemical compounds in foods to provide fuel for energy (measured in kilocalories), growth, maintenance and to regulate body processes
Six classes: carbohydrates, fats, protein, vitamins, minerals, water
Energy: The capacity to do work. The energy in food is chemical energy, it can be converted to mechanical energy in the body.
Food energy is measured in calories

6. Meet the Nutrients Six classes of Nutrients Water Carbohydrates
Protein
Fat
Vitamins
Minerals

7. The Nutrients Chemical composition of Nutrients
Organic – contain carbon
Carbohydrate
Protein
Lipids
vitamins
Inorganic – do not contain carbon
Water
minerals

8. The Nutrients 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 (Macronutrients)
The nutrients that break down to yield energy the body can use
Carbohydrate
Fat
Protein

9. Energy-Yielding Nutrients
Calories and kilocalories
Calories are units by which energy is measured. Food energy is measured in kilocalories (kcal)
Carbohydrate = 4 kcal/gram
Protein = 4 kcal/gram
Fat 9 = kcal/gram

10. Energy from Foods
Energy density – a measure of the energy a food provides relative to the amount of food (kcal per gram)
Lower energy density – provides low kcal per gram
Higher energy density - provides high kcal per gram

11. Lower energy density Higher energy density
This 450-gram breakfast delivers 500 kcal, for an energy density of 1.1 (500 kcal/450 g = 1.1 kcal/g)
Higher energy density
This 144-gram breakfast delivers 500 kcal, for an energy density of 3.5 (500 kcal/144 g = 3.5 kcal/g)

12. Nutrients and Their Functions

13. Other Nutrients Minerals Water Vitamins Organic Not energy-yielding
Essential nutrient
Water-soluble vs. fat-soluble
Vulnerable to destruction
Minerals
Inorganic
Indestructible
Water

14. Dietary Reference Intakes (DRI)
Estimated Average Requirements -(EAR)
defines the requirement of a nutrient that supports a specific function in the body for half of the healthy population.
Recommended Dietary Allowances – (RDA)
use the EAR as a base
include sufficient daily amounts of nutrients to meet the known nutrient needs of all healthy populations.
This recommendation considers deficiencies.

15. Dietary Reference Intakes
Adequate Intakes (AI)
reflect the average daily amount of a nutrient without an established RDA that appears to be sufficient.
Tolerable Upper Intake Level (UL)
is a 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.

16. Energy Recommendations
Estimated Energy Requirement –EER
average daily energy intake to maintain energy balance and good health for population groups.
Acceptable Macronutrient Distribution Ranges (AMDR)
range of intakes for energy nutrients that provide adequate energy and nutrients and reduce risk of chronic disease.
Carbohydrate: 45% - 65%
Fat: 20% - 35%
Protein: 10% - 35%
RDA –
Protein - .8g/kilogram
Based on weight

17. Facts about the Recommendations
Estimates of adequate energy apply to healthy people
Not optimal intakes for all individuals
Nutrients are intended to be met through variety of foods
Recommendations apply to average daily intakes
DRI serve a unique purpose – to keep population healthy and prevent chronic diseases
EAR – is for groups
RDA – for individuals

18. Nutrition Assessment
What happens When a Person Doesn’t Get Enough or Gets Too much of a nutrient or energy?
Malnutrition – Any condition caused by deficiency or excess food energy or nutrient intake over time.
Undernutrition – Deficient energy or nutrients.
Overnutrition – Excess energy or nutrients

19. Nutrition Assessment of Individuals
Evaluates the many factors that influence or reflect nutritional health.
Historical information regarding diet, health status, drug use, and socioeconomic status is gathered.
Anthropometric data measure physical characteristics including height and weight.
Physical examinations require skill and reveal possible nutrition imbalances.
Laboratory tests detect early signs of malnutrition.

20. Nutrition Assessment of Individuals
Stages in Nutrient Deficiency (example is given for iron)
Overt is easy to observe
Primary deficiency is inadequate dietary intake
Secondary deficiency is caused by disease or drugs
Sub-clinical deficiency is the early stages of deficiency without outward signs
Covert is hidden

22. Nutrition Assessment of Populations
National nutrition surveys
National Nutrition Monitoring Program uses survey research to collect data on foods people eat and people’s health status.
Data collected is used for nutrition policy, food assistance programs and food supply regulation
National health goals
Healthy People is a national public health initiative under the U.S. Department of Health and Human Services that is published every 10 years.
Identifies the most significant threats to health
Focuses efforts on eliminating these threat

23. Nutrition Assessment of Populations

25. Diet and Health

26. Diet and Health

27. How Does the Average American Diet Stack Up?
Average American diet is high in:
Sodium
Saturated fat
Calories
Average American diet is low in:
Vitamin E
Calcium
Fiber

28. How Does the Average American Diet Stack Up?
Incidence of overweight and obesity is on the rise.
65% of American adults and 15% of children (ages 6 to 19) are overweight
Take in more calories than needed
Burn fewer calories due to sedentary lifestyles
Resulting in increased rate of type 2 diabetes (especially children), heart disease, cancer, and stroke

29. Obesity Trends Among U.S. Adults
Figure 1.3

30. The Science of Nutrition
Observational Research: involves looking at factors in two or more groups of subjects to see if there is a relationship to certain health outcomes
Epidemiological research: study of populations of people
Example: Relationship of sun exposure and incidence of rickets in Norway compared with Australia
May be due to other unidentified diet or lifestyle factors

31. The Science of Nutrition
Experimental Research: involves at least two groups of subjects
Experimental group: given a specific treatment
Control group: given a placebo (“sugar pill”)
Double-blind placebo-controlled experiment is “gold standard.”
Neither scientists nor subjects know which group is receiving which treatment.
All variables held the same and controlled for both group.
Sample size – number of people in the study.

32. The Science of Nutrition
Hypothesis – an educated guess to answer a question. For example: “what foods or nutrients might protect against hypertension?” The hypothesis = “Foods low in sodium and high in potassium help reduce risk of hypertension”

33. Controlled Experiments: Scientists use experimental research to test hypotheses.
Figure 1.6

34. What’s the Real Deal When It Comes to Nutrition Research and Advice?
Newspaper headlines and television news items report results of a single, recent research study.
Advice from authoritative health and nutrition organizations is based on:
Consensus: the opinion of group of experts based on collection of information

35. Evaluating Media Headlines with a Critical Eye
Before making dietary and lifestyle changes based on media reports, read with a critical eye and ask:
Was the research finding published in a peer-reviewed journal?
Was the study done using animals or humans?
Do the study participants resemble me?
Is this the first time I’ve heard about this?
Wait until research findings are confirmed and consensus reached by reputable health organizations before making changes.

37. Quackwatchers Beware of health quackery and fraud:
Promotion and selling of health products and services of questionable validity
Sales people introduce health fears and make false nutrition claims and unrealistic promises and guarantees.
helps consumers identify quackery and fraud.

38. You Can Trust the Advice of Nutrition Experts
Registered Dietitian (RD): completed at least a bachelor’s degree at an accredited U.S. college or university and a supervised practice, passed a national exam administered by the American Dietetic Association
Public Health Nutritionist: has degree in nutrition but may not be an RD (if didn’t complete supervised practice, not eligible to take ADA exam)
Professionals holding advanced degrees in nutrition
Licensed dietitian (LD): licensed by state licensing agencies

39. Obtaining Accurate Nutrition Information on the Internet
National Institutes of Health (NIH) 10 Questions to consider when viewing a health-related website
Who runs the site?
Who pays for the site?
What is the purpose of the site?
Where does the information come from?
What is the basis of the information?

40. Obtaining Accurate Nutrition Information on the Internet
How is the information selected?
How current is the information?
How does the site choose links to other sites?
What information does the site collect about you and why?
How does the site manage interactions with visitors?

41. Homework
For 5 point extra credit, provide answers to the following questions:
What is the World Food Day
Who/what organization founded it
What year was it founded
What is the theme for 2007
Complete a family Health History worksheet
Bring a food label to class next time
The food label must be a food that contains nutrients (Kcal, fat & protein)
Must be submitted next class. No exceptions.