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C HAPTER
1
The Role of Nutrition
in Our Health
PowerPoint® Lecture Slides prepared by
James Bailey, University of Tennessee
Copyright © 2009 Pearson Education, Inc.,
publishing as Pearson Benjamin Cummings.
What Is Nutrition?
Nutrition: is an interdisciplinary and applied study of
food, including
 How food nourishes our bodies
 How food influences our health (mind and body)
Compared with other fields, nutrition is a relatively
new discipline of science.
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Why Is Nutrition Important?
Nutrition contributes to wellness.
Wellness: the absence of disease
 Physical, emotional, and spiritual health
Critical components of wellness
 Nutrition
 Physical activity
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Why Is Nutrition Important?
Nutrition encompasses the following aspects of food
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Consumption
Digestion
Absorption
Metabolism
Storage
Excretion
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Why Is Nutrition Important?
Nutrition also studies these aspects of food
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Psychological
Food safety
Global food supply
Cultural
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Why Is Nutrition Important?
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Figure 1.1
Why Is Nutrition Important?
Nutrition can prevent disease.
 Nutrient deficiency diseases:
 rickets (vitamin D)
 goiter (iodine)
 scurvy (vitamin C)
 Diseases influenced by nutrition:
heart disease; diabetes; high blood pressure;
osteoarthritis, osteoporosis
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Why Is Nutrition Important?
Obesity is a growing problem
across the globe – changes in
obesity that took developing
world nations, such as the US
two to four decades to occur
are taking place in emerging
nations at 2x the pace or
faster!
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Figure 1.2
Promoting Better Nutrition for All
The World Health Organization and member states
began a campaign called: Five Keys to a
Healthy Diet:
1.
2.
3.
4.
5.
Give your baby only breast milk for the first six months of life;
Eat a variety of foods;
Eat plenty of fruits and vegetables;
Eat moderate amounts of fat and oils;
Eat less salt and sugars.
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
What Are Nutrients?
Nutrients: the chemicals in foods that are critical to
human growth and function.
carbohydrates
vitamins
fats and oils
minerals
proteins
water
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What Are Nutrients?
Macronutrients: nutrients required in relatively large
amounts (g or Kg).
 Provide energy
 Carbohydrates; fats and oils; proteins
Micronutrients: nutrients required in smaller
amounts (g or mg).
 Vitamins and minerals
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Energy from Nutrients
We measure energy in kilocalories (kcal) or
kiloJoules (kJ).
On food labels in America, the term “calorie”
appears. It should actually state: kilocalories.
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Carbohydrates
 Primary source of fuel for the body, especially for
the brain
 Provide 4 kcal (or 17 kJ) per gram
 Carbohydrates are found in grains (wheat, rice),
vegetables, fruits, and legumes
 Sugars are also carbohydrate
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Fats and Oils
 Are composed of lipids, molecules that are
insoluble in water
 Provide 9 kcal (38 kJ) per gram
 Are an important energy source during rest or low
intensity exercise
 Are found in butter and vegetable oils
 Are source of fat-soluble vitamins and essential
fatty acids
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Proteins
 Are chains of amino acids
 Can supply 4 kcal (17 kJ) of energy per gram, but
are not a primary energy source
 Are an important source of nitrogen
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Proteins
Proteins are important for
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Building cells and tissues
Maintaining bones
Repairing damage
Regulating metabolism
Fluid balance
Protein sources include meats, fish, dairy products,
seeds, nuts, and legumes.
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Vitamins
Vitamins: organic molecules that assist in regulating
body processes. [Organic means that the molecule contains carbon atoms.]
Vitamins are micronutrients needed to support the
body. They do not yeild energy, so they have no kcal
or kJ in them. There are two categories:
1. Fat-soluble vitamins
2. Water-soluble vitamins
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Vitamins
Fat-soluble vitamins
 Vitamins A, D, E, and K
 Dissolve easily in fats and oils
Fat-soluble vitamins can be stored in the body.
Toxicity can occur, especially from vitamin A.
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Vitamins
Water-soluble vitamins
 Vitamin C and the B vitamins
 Remain dissolved in water
Excess water-soluble vitamins are eliminated by the
kidneys daily and cannot be stored in our bodies.
This is why we must eat more of these vitamins each
and every day.
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Minerals
Minerals: inorganic substances required for body
processes. They are atoms, not molecules.
Minerals include, for example:
sodium, calcium, iron, potassium, and magnesium.
Minerals have many different functions such as fluid
regulation, bone structure, muscle movement, and
nerve functioning.
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Minerals
Our bodies require at least 100 mg/day of the major
minerals such as calcium, phosphorus, magnesium,
sodium, potassium, and chloride.
We require less than 100 mg/day of the trace
minerals such as iron, zinc, copper, iodine, and
fluoride.
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Water
Water is a critical nutrient for health and survival.
Water is involved in many body processes.
fluid balance
nutrient transport
nerve impulses
removal of wastes
muscle contractions
chemical reactions
many, many more…
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Determining Nutrient Needs
Dietary Reference Intakes (DRIs): updated
nutritional standards.
 Expand on the traditional RDA values
 Set standards for nutrients that do not have RDA
values
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Determining Nutrient Needs
DRIs identify the
 Amount of a nutrient needed to prevent deficiency
disease in healthy people
 Amount of a nutrient which may reduce the risk of
chronic disease
 Upper level of safety for nutrients
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs
Figure 1.8
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs
DRIs consist of four values
1.
2.
3.
4.
Estimated Average Requirement (EAR)
Recommended Dietary Allowances (RDA)
Adequate Intake (AI)
Tolerable Upper-Intake Level (UL)
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs
Estimated Average Requirement (EAR)
 The average daily intake level of a nutrient that will
meet the needs of half of the people in a particular
category
 Are used to determine the Recommended Dietary
Allowance (RDA) of a nutrient
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Determining Nutrient Needs: EAR
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Figure 1.9
Determining Nutrient Needs
Recommended Dietary Allowances (RDA)
 The average daily intake level required to meet the
needs of 97 to 98% of people in a given life stage
and gender
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs: RDA
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Figure 1.10
Determining Nutrient Needs
Adequate Intake (AI)
 Recommended average daily intake level for a
nutrient
 Based on observations and estimates from
experiments
 Used when the RDA is not yet established: calcium,
vitamin D, vitamin K, fluoride
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs
Tolerable Upper Intake Level (UL)
 Highest average daily intake level that is not likely
to have adverse effects on the health of most people
 Consumption of a nutrient at levels above the UL is
not considered safe
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs
Estimated Energy Requirement (EER)
 Average dietary energy intake (kcal) to maintain
energy balance
 Based on age, gender, weight, height, and level of
physical activity
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs
Acceptable Macronutrient Distribution Ranges
(AMDR)
 The portion of the energy intake that should come
from each macronutrient
 The range of energy intake from carbohydrate, fat,
and protein associated with reduced risk of chronic
disease
 The range of macronutrient intake that provides
adequate levels of essential nutrients
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Determining Nutrient Needs: AMDR
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Table 1.4
Nutrition Research
The scientific method
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Observation: describe the phenomenon
Create a hypothesis
Design, collect, and analyze the data
Interpret the data
Generalize the findings, develop a theory
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Research Models
 Epidemiological studies
 Human experiments
 Case control studies
 Clinical studies
 Animal studies
Note: Each type of study has advantages and
disadvantages.
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Research Study Factors
 Controls
 Does not receive treatment
 Sample size
 Appropriate to measure a difference between
treatment groups
 Placebo
 Similar appearance and taste
 Double-blind
 Neither subjects nor researchers know who is in the
placebo or treatment groups
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Evaluating Media Reports
Ask these questions to determine the scientific
validity
 Who is reporting the information?
 Who conducted the research and who paid for it?
 Is the report based on reputable research studies?
 Was there a control and an experimental group?
 Was the sample size large enough to rule out
chance variation?
 Was a placebo effectively administered?
 Was the experiment double blind?
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