An Overview of Nutrition

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Chapter 1

• An Overview of Nutrition

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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.

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Overview of Nutrition

• Nutrition
• 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

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What Drives Our Food Choices?

• 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
• Phytochemicals nonnutrient compounds that
  contribute to health and may play a role in
  fighting chronic diseases

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Food Choices

• We choose foods for many other reasons beyond the
  basic need to obtain nutrients
• Taste and culture
• Social reasons and trends
• Advertising
• Time and convenience
• Habits and emotions

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The Nutrients

• Six classes of Nutrients
• Carbohydrates body's main source of energy or
  calories
• Protein supplies energy and amino acids, which
  are building blocks of every cell in the body.
• Fat Fats transport nutrients and provide storage
  and insulation for your body
• Vitamins needed in very small amounts in the
  diet to regulate chemical reactions. Each vitamin
  has a specific job in the body, so one vitamin
  can't replace another.
• Minerals are like vitamins and are used in the
  body to promote chemical reactions and form body
  structures.
• Water Water is needed to help regulate body
  temperature. Water makes up 55-75 of your body
  weight.

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Nutrients and Their Functions
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The Nutrients

• Composition of foods
• Inorganic nutrients does not contain carbon
• Water
• Minerals
• Organic Nutrients carbon to carbon or carbon to
  hydrogen bonds
• Carbohydrates
• Proteins
• Lipids
• Vitamins

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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)
• Energy is measured in Calories (calories,
  kilocalories, kcalories, kcal).
• The nutrients that break down to yield energy the
  body can use
• Carbohydrate
• Fat
• Protein

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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
• Alcohol 7 kcal/gram
• Energy density
• A measure of the energy a food provides to the
  amount/weight of food (kcal per gram)

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Lower 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)
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Other Nutrients

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

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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

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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

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Obesity Trends Among U.S. Adults
Figure 1.3
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Dietary Reference Intakes

• 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.
• 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.

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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
• Energy RDA
• Men vs. women
• Ages
• RDA Protein - .8g/kilogram
• Based on weight

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Using Nutrient Recommendations

• Recommendations should be met by consuming a
  varied diet
• Recommendations apply to average daily intakes
• Each DRI category serves a unique purpose

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Nutrition Assessment

• 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.

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Nutrition Assessment

• 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

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Nutrition Assessment of Populations

• National nutrition surveys
• National Nutrition Monitoring Program uses survey
  research to collect data on foods people eat and
  peoples 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

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Nutrition Assessment of Populations
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Diet and Health
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Diet and Health
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Whats 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

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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 Ive heard about this?
• Wait until research findings are confirmed and
  consensus reached by reputable health
  organizations before making changes.

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Sound Nutrition Research Begins with the
Scientific Method
Figure 1.4
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A Hypothesis Can Lead to a Scientific Consensus
Figure 1.5
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Research Studies and Experiments Confirm
Hypotheses

• 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

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Research Studies and Experiments Confirm
Hypotheses

• 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 groups

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Controlled Experiments Scientists use
experimental research to test hypotheses.
Figure 1.6
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You Can Trust the Advice of Nutrition Experts

• Registered Dietitian (RD) completed at least a
  bachelors 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 didnt
  complete supervised practice, not eligible to
  take ADA exam)
• Professionals holding advanced degrees in
  nutrition
• Licensed dietitian (LD) licensed by state
  licensing agencies

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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.
• http//quackwatch.org helps consumers identify
  quackery and fraud.

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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?

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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?