An Overview of Nutrition

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Chapter 1

• An Overview of Nutrition

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I. Introducing the Nutrients

• A. Six classes of nutrients
• 1. Water
• 2. Carbohydrate (CHO) excluding fiber
• 3. Protein
• 4. Fats (lipids)
• 5. Minerals
• 6. Vitamins

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Introducing the Nutrients (cont)

• B. Composition of foods we consume
• 1. Similar to the composition of the body
• 2. Primarily water, protein, fat and CHO
• C. Composition of the body
• 1. Similar to the composition of foods we
  consume
• 2. Primarily water, protein, fat and CHO

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D. Chemical Composition of Nutrients

• 1. Inorganic compounds (do not contain
  carbon)
• a. Minerals 1. Elements, the simplest
  nutrient
• 2. Iron, selenium, potassium, sodium
• 3. Indestructible 4. Do not yield energy

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Inorganic compounds (do not contain carbon)
(cont)

• b. Water 1. Essential compound 2. Does not
  yield energy

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2. Organic compounds (contain carbon)

• a. Vitamins 1. Essential compounds a.
  Body cannot make (synthesize) 2. Some are
  easily destroyed 3. Water and fat soluble
  4. Do not yield energy

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Organic compounds (contain carbon) (cont)

• b. CHO 1. Sugars, starches and fibers
  2. Yields energy
• c. Proteins 1. Amino acids a.
  Essential and non-essential 2. Yields energy

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Organic compounds (contain carbon) (cont)

• d. Fats
• 1. Fatty acids a. Essential and
  non-essential 2. Yields energy

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Composition of the Nutrients
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II. Science of Nutrition

• A. Scientific Method
• 1. Define problem, propose hypothesis,
  test hypothesis, interpret data, define
  additional problems, propose hypothesis...

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Scientific Method
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B. Nutrition research

• 1. Epidemiological studies
• a. Population based
• b. Relationships between any number of
  factors
• 1. Cancer and vegetable consumption
• 2. Case-control studies
• a. Subjects with and without particular
  factor of interest

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Nutrition research (cont)

• 3. Animal studies
• a. Positive and negative controls
• b. Determine nutrient requirements
• 4. Human intervention (clinical trials)
• a. Use of human subjects to assess
  efficacy of treatment

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C. Terminology

• 1. Control
• a. Group identical to experimental group to
  control for variation in parameter of interest
  
• b. Positive and negative
• 2. Sample size
• a. Must have sufficient number of subjects to
  account for inherent variability among subjects

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Terminology (cont)

• 3. Placebo
• a. Fake treatment
• 4. Double blind
• a. Neither researcher nor subject are aware of
  treatment
• 5. Correlation and cause
• a. Correlation
• 1. Suggests a relationship
• 2. Does not suggest cause

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III. Dietary Reference Intakes

• A. Data derived from scientific studies
• 1. Estimated average requirements
• a. Population average of the amount of a
  nutrient to required to maintain a
  specific function
• 2. Recommended Dietary Allowance (RDA)
• a. Nutrient intake of healthy population
• b. Intake-output balance studies
• c. Animal research
• d. Reviewed every few years
• e. Dependent upon sex and age

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Recommended Dietary Allowance (cont)

• f. RDA for Vitamins and minerals
• a. Many vitamins and minerals have RDAs
  however many do not
• g. Setting the RDA
• a. Compare vitamin C with energy
• 1. The RDA for energy is set at the
  population mean for that age and sex
• 2. The RDA for Vitamin C is set at two
  standard deviations above the population
  mean so that 98 of the population is covered

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RDA
The RDA for a nutrient is not set at the
population mean but rather at a level that will
include 98 of the population. If it were set
at the mean, 50 of the population would consume
less than their requirement. The RDA for energy
is set at the population mean. If the same logic
that the nutrient RDA is set by were applied to
energy a large number of people would be
consuming too many calories.
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Nutrients Needs
Two views on nutrient intake. The one on the
left suggests that if a little is good for you
then a lot must be very, very good for you. One
must remember that nutrients, especially vitamins
and minerals, are chemicals and elements. As
with any other chemical or element they can be
toxic at high doses. The chart on the right is
the correct view of nutrient intake. The RDA is
set at a safe level. Deviations above and below
this amount are generally safe. However extreme
deviations from the RDA can produce deficiencies
or toxicities.
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Dietary Reference Intakes (cont)

• 3. Adequate intakes
• a. nutrients with insufficient data to
  determine RDAs
• b. adequate intake in one person may not be
  adequate for another
• 4. Tolerable upper intake levels
• a. level above which a nutrient is likely to
  be toxic

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IV. Food Choices

• A. Personal preferences
• 1. Fondness for a certain food
• B. Habit
• 1. Cereal or toast every morning
• C. Ethnic heritage or tradition
• 1. Eat what you were raised on
• 2. Culturally determined
• a. Sweets, spicy

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Food Choices (cont)

• D. Social interactions
• 1. Get togethers for pizza etc.
• E. Availability, convenience and economy
• 1. Quick, easy, affordable
• 2. Food deliveries, eating out

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Food Choices (cont)

• F. Positive and negative associations
• 1. Positive
• a. hot dogs at ball games etc.
• b. Holiday meals
• 2. Negative a. sickness attributed to
  consuming a particular food b. Parents
  made you eat a food you did not care for
• G. Emotional comfort
• 1. Eating when stressed

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Food Choices (cont)

• H. Values
• 1. Religious, political or environmental
  concerns
• I. Body image
• 1. Eat protein to add muscle (fallacy)
• 2. Chocolate and acne
• J. Nutrition
• 1. Eat a food because it is good for you

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V. Nutrition Assessment

• A. Nutrition assessment of individuals
• 1. Determine the nutritional status of a
  person
• B. Methods of nutrition assessment 1.
  Historical information a. Health b.
  Socioeconomic status 1. Financial ability
  c. Medications

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Historical Information (cont)

• d. diet history
• 1. Types
• a. 24 hour recall
• b. 3 day record
• c. Food frequency
• 2. Information Provided
• a. indicates under and over nutrition of
  specific nutrients

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Methods of nutrition assessment (cont)

• 2. Anthropometric data
• a. Objective measurements such as height and
  weight
• 3. Physical examinations
• a. Hair, skin, tongue, fingernails, color
• 4. Laboratory tests
• a. Analysis of blood and urine
• 1. Iron and hemoglobin for example

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Stages in the Development of a Nutrient
Deficiency
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C. Nutrition assessment of populations

• 1. Analyzes similar to that with individuals
• a. Food consumption surveys
• 1. Generally assess food disappearance
• 2. National food consumption survey
• b. Nutrition status survey
• 1. assess the nutritional status of
  populations using the before mentioned
  techniques
• 2. National Health and Nutrition
  Examination Survey (NHANES)
• a. between 40,000 and 70,000
  people

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VI. Diet and Health

• A. Nutrition related diseases
• 1. Nutrition involved in the etiology
  and/or management of the disease
• B. Risk factors
• 1. Factors that are associated with diseases
• a. Salt and high blood pressure
  (hypertension)
• b. Fat and certain cancers
• c. Fat and heart disease

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Ten Leading Causes of Death Illness
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VII. Dietary Recommendations

• A. Diet and Health Recommendations for
  Populations
• 1. Developed by the Committee on Diet and
  Health
• 2. State an improvement in health of the
  overall population could occur with dietary
  changes and weight control

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Dietary Recommendations (cont)

• B. Recommendations for Individuals
• 1. Take into account your family history of
  diseasea. High blood pressure and heart
  disease
• b. High blood cholesterol and heart disease