Nutrients
Macro
Micro
What is the point of each?
What are Nutrients?
• Organic* (contain Carbon) &
Inorganic molecules in food
that are critical to human
growth and function
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Carbohydrates *
Lipids (Fats and oils) *
Proteins *
Vitamins *
Minerals
Water
Divisions of Nutrients
• Macronutrients
– provide energy to do
work* & building
blocks for cell
structures
– Fats, carbs, proteins
– Required in large
amounts
– Broken down and
stored or rebuilt
• Micronutrients
– Required in much
smaller quantities
– Vitamins and minerals
– Used primarily “as-is”
Energy of macronutrients
• Measured in
kilocalories (kcal) =
Energy required to
raise the temp. of 1g
of H2O by 1°C.
• Via bomb calorimetry
• On food labels,
“Calorie” usually
means kcal.
Energy Density of Two Breakfast Options Compared
LOWER ENERGY DENSITY
HIGHER ENERGY DENSITY
This 450-gram breakfast delivers 500
kcalories, for an energy density of 1.1
(500 kcal ÷ 450 g 1.1 = kcal/g).
This 144-gram breakfast also delivers
500 kcalories, for an energy density of 3.5
(500 kcal ÷144 g = 3.5 kcal/g).
Carbohydrates
• Primary source of Energy during activity
(especially for our brain)
• C, H and O in ratio of 1:2:1
• Provides 4 kcal/g
Fats (Lipids)
• Triglycerides, phospholipids
• Important source of Energy during rest
and low intensity activity
• Provide 9 kcal/g (far fewer Oxygens)
Proteins
• Contain C, H, O & Nitrogen (N)*
• Constructed of chains of Amino Acids (AA)
• Energy source only in dire need; 4 kcal/g
• Important for:
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Proteins
Bone structure (organic part of bones is protein)
Regulating metabolism & fluid balance
Repairing muscle & bone
Build cells and tissues
Clicker Q
•
Which of the following meals is the
most energy dense?
1. One 100g, 500 kcal steak
2. One 180g apple, with 120 kcals & one
170g banana with 200 kcals
3. Two donuts, at 70g & 200 kcal each
Table 1-2
Page 9
Calculating Energy of foods
• 1 slice bread with 1 tbsp. peanut butter
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Carbs: 16g * 4 kcal/g
Protein: 7g * 4 kcal/g
Fat: 9g * 9 kcal/g
Total
= 64 kcal
= 28 kcal
= 81 kcal
= 173 kcal
Vitamins
• Micronutrients (only need a little; e.g. mg,
µg)
• 1 g = 1,000 mg (milligrams)
• 1 mg = 1,000 µg (micrograms)
• 1g = 1,000,000 µg
Vitamins
• Organic compounds that assist in
regulating body processes and using E (do
not supply E)
• 2 types based on solubility
– Fat-soluble
– Water-soluble
Fat-soluble vitamins
• Vitamins A, D, E, K
• Easily dissolve in fats and oils
• Easily stored in adipose tissue (fat cells)
throughout the body
– Unnecessary to ingest or synthesize these
every day
Water-soluble vitamins
• Vitamins C, B (thiamin, B6, riboflavin,
folate, etc.)
• Must ingest or synthesize these every
day
– kidneys filter them from the blood & you
excrete them in urine
Minerals
•Inorganic compounds (no Carbon)
•Remain intact (maintain same structure,
regardless of their environment)
• Major
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Sodium (Na+)
Chloride (Cl-)
Potassium (K+)
Calcium (Ca2+)
Phosphorous (P)
Magnesium (Mg2+)
• Minor
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Iron
Zinc
Iodine
Selenium
Copper
Flouride
Chromium
Molybdenum
Minerals
• Essential to:
– Bone deposition (Ca, P, Mg)
– Delivering O2 to cells and removing CO2 (Fe)
– Initiating & sustaining muscle contraction (Na,
K, Ca)
– Propagating nerve impulses (Na, K, Ca)
– Fluid balance & blood pressure (Na, K, Cl)
H2O
~ 2/3 of total body weight
• Dissolves organic and inorganic molecules
making a solution (~55% of blood volume is water)
• Product or substrate for chemical reactions
– Hydrolysis & dehydration synthesis
• Extremely Stable
– Absorbs and retains heat without changing temp. or
state!
– Great medium for cooling the body
• Lubricates moving parts
– Reduces friction
• Buffers against pH change
Determining Nutrient Intake
How much of each nutrient do I
need?
Dietary Reference Intakes
(DRI)
• Update traditional Recommended
Daily Allowances (RDA) nutritional
standards
• Establish standards for nutrients
without RDA values
Dietary Reference Intakes
micronutrients
macronutrients
Dietary Reference Intakes
• DRIs consist of 4 values:
1. Estimated Average Requirement (EAR)
2.Recommended Dietary Allowances (RDA)
3.Adequate Intake (AI)
4.Tolerable Upper-Intake Level (UL)
Dietary Reference Intakes
• Estimated Energy Requirement (EER)
• Average energy intake (kcals) needed to
maintain energy balance (neither gaining
nor losing weight)
• Based upon:
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Age
Gender
Weight
Height
Level of physical activity
EAR & RDA
Naive vs. Accurate View of Nutrient Intakes
Danger
of toxicity
Marginal
Tolerable
Upper Intake
Level
Safety
Safety
RDA or AI
RDA
Marginal
Danger
Danger
of
deficiency
Naive
view
Accurate
view
Estimated
Average
Requirement
Dietary Reference Intakes
• Acceptable Macronutrient Distribution Range
(AMDR)
• Describes the portion of energy intake that
should come from each macronutrient
Nutrient
AMDR
Carbohydrate
45 - 65%
Fat
20 - 35%
Protein
10 - 35%
How do nutritionists figure
this out?
Using the
scientific
method
•Observation
•Hypothesis
•Prediction
•Experiment
•Results
•Interpretations
The Scientific Method
Examples of Research Designs
EPIDEMIOLOGICAL STUDIES
COHORT
Heart attack
CROSS-SECTIONAL
Examine a cultural or
ethnic group of people at
a single snapshot in time.
Attempt to identify
factors contributing to
health
Blood cholesterol
Examine a group of people
at multiple time steps.
Watch for problems that
develop & correlate
eating patterns that
contribute to disease.
Examples of Research Designs
EXPERIMENTAL STUDIES
LABORATORY-BASED
ANIMAL STUDIES
Feed one group of
mice an experimental
diet.
Others get a control
diet.
LABORATORY-BASED
IN VITRO STUDIES
HUMAN INTERVENTION
(OR CLINICAL) TRIALS
Change eating
habits of a group.
See if disease
symptoms
improve.
A well- designed experiment
• Sample Size
• Blind
– Placebo
• Double-blind
– Researcher fallibility
• Correlation vs.
Causation
Your Goal
• Create a diet plan that is:
– nutritionally adequate
– allows you to maintain a healthy weight
– support your daily physical activities