Transcript Nutrition: - Pearson Canada

Chapter 7
Nutrition:
Eating For Optimal Health
Many Dietary Choices
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Exotic and foreign foods
dietary supplements
artificial sweeteners/flavors
no-fat, low-fat & artificial
fats
• cholesterol free, high
protein, highcarbohydrate & low calorie
Healthy Eating
• Hunger……..a physiological need to
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eat
Energy requirement in today’s society
work, school, history, preference
cultural preferences for FOOD
economic status
food security issues
• Appetite…… desire to
eat…..associated with hunger….more
psychological…..
Nutrition
Science of food
• relationship between physiological
function and essential elements in
food
Nutrients
• proteins,carbohydrates (CHO),
fats, vitamins, minerals & Water
(H2O)
“Diets of Affluence”
• high fat & calories
• red meat / potatoes/ rich deserts
• recent trends…..more white meats
and more fruits and vegetables
•A preoccupation
of food
•eating too much
of the wrong foods
•disordered eating
• BUT!!!!! Heart disease, cancer,
hypertension, cirrhosis of the
liver, tooth decay and chronic
obesity…….
……..still major health risks!
Responsible Eating:
Changing Old Habits
• Consume more
calories then we need
• calorie - a
measurement of
energy potential in
food
• CHO:
4 Kcal/g
• FAT:
9 Kcal/g
• PROTEIN: 4 Kcal/g
Nutrition
PROCESS:
nutrients are absorbed from the
small intestine into bloodstream
for use by cells
metabolized into usable
compounds
for building/repair/muscular
work.
NUTRITION IS IMPORTANT
FOR…………
• energy production for
muscular work growth
and synthesis of body
materials
• providing materials for
tissue maintenance
• regulation of bodily
processes
The Digestive Process
• Provides the body with
chemicals for energy and body
maintenance
• essential nutrients delivered via
food intake
• broken down to be absorbed
and delivered to cells
3,000,000,000,000
The Process…………………….
Start: Mouth - salivary glands (saliva) prepares food / moistens / breakdown
Esophagus Tube: 20 to 25cm connects mouth to stomach
Stomach: HCL acid + food + enzymes
= mixture mucus lines stomach for
protection
Small Intestines: 8 meters long
3 parts - duodenum, jejunum & ileum
secretes digestive enzymes + liver
pancreas (Fats, Proteins + CHO)
Nutrients are Absorbed Into Blood
The Liver:
• determines
destination - stored,
sent to cells, organs
or excreted
The Large Intestine:
solid wastes (fiber,
water,salts etc)
The Calorie
• Calorie:
• a unit for measuring the energy of food 1 calorie produces enough energy to raise the
temperature of 1g of water 1 degree
• caloric measurements are made in thousands
of calories therefore the term calories is
interchangeable with Kilocalories ( kcal.)
RDA
(Recommended Dietary Allowance)
• the levels of nutrient
intake that is
necessary for the
maintenance of good
nutrition of practically
all healthy persons.
Factors causing variations in
food requirements:
• Age
• sex
• physical size
• activity level
• pregnancy
• convalescence
Energy Balance
Isocaloric Balance
Positive Balance
Negative Balance
CARBOHYDRATES (CHO’s)
• compound consisting of
carbon,
hydrogen and oxygen
(C6H12O6)
• most efficient energy source
both immediate and time
released
• average Canadian diet has
46% kcal from CHO;
• energy yield = 4 Kcal/g.
Main function….. CHO’s
• energy
• also rich in vitamins, minerals,
and water.
• when CHO enters the body, it
is converted to glucose, the
energy source for cells (very
important for nervous system
and brain).
Categories of Carbohydrates:
SIMPLE: c-c-c-c-c-c
COMPLEX CHO: c-c-c-c-c-c-c-c-c-c-c-c-c-c-c-c-cc-c-c-c-c-c-c-c-c-c-c-c
Simple Sugars
• composed of one or
two simple sugar
units (fructose,
glucose and
galactose)
• found mainly in fruits
provide immediate
energy
Two forms of simple sugar:
Monosaccharides:
• consist of one molecule
of sugar - the structural
unit of simple CHO
(fructose, galactose, and
glucose).
Disaccharide:
combination of Monosaccharides
includes sucrose, which is table
sugar - combination of 1 fructose
plus 1 glucose molecule
Lactose (milk products) = 1
glucose plus 1 galactose
molecule
Maltose = 2 glucose molecules
PROCESSED SUGAR
CONSUMPTION IN CANADA:
Mean consumption for each Canadian
over 15 years = 150 lbs. of sugar per
year - 75% in form of processed
foods and beverages
• This represents more than 20-25% of
caloric intake
• 33 teaspoons of sugar per day = 6
stalks of sugar cane
• tooth decay
DISADVANTAGES OF HIGH SUGAR
INTAKE
Processed sugars - poor
CHO - contain no other
nutrients i.e. no vitamins
and minerals
EMPTY CALORIES
results in a situation where
100% of nutrients must be
obtained from 75% of
calories in the diet.
COMPLEX CHO (polysaccharides)
• composed of three or
more simple sugars
bonded together
• found in grains, fruits,
stems, roots, and
leaves of vegetables
• provide longer lasting
energy
Three Types of CHO
Starches:
plant source - whole grain foods, rice,
potatoes
Fiber (Cellulose):
not digested by enzymes in small intestine
insoluble: speeds movement of foods
through digestive tract, increases fecal bulk
and maintains regularity of bowel
movement
CHO……...
Soluble fiber: digested in
the large intestine (fruits,
veggies oat bran,dried
beans)
decreases blood cholesterol
and cardiovascular disease
Controls pacing of
absorption of CHO into
bloodstream.
Prevents dramatic swings
in blood sugar levels
Canadians Should double their
intake of fiber, bulk, roughage…
20 to 30 grams
Protection against:
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colon/rectal cancer
breast cancer
constipation
diverticulosis
heart disease
diabetes
obesity
Eat Less Processed Food to
Increase Fiber Intake
CARCINOGENS - ?
• skins of fruits &
veggies
• fiber from food rather
than pills/powder
• spread out fiber
intake
• drink plenty of liquids
I’m soooo hungry
I could eat a
Vegetable!
EATING TOO MUCH CHO !
CAN IT BE TRANSFORMED INTO FAT?
Glycogen
glucose molecules
bonded together
stored mainly in liver and
muscle
relatively fast energy for
muscles
FATS
Many negative associations with fat
essential for insulation and maintenance
of body temperature
padding
healthy skin and hair
proper cell function
carrying of fat-soluble vitamins A, D, E,
K to cells
add flavor and texture to our food
high-energy yield = 9 Kcal/g
Two major types:
Triglycerides and Steroids
• 95% of total fat in body
• excess Kcal are converted to
Triglycerides and stored in
adipose tissue (fat cells)
• each triglyceride is composed of
three fatty acid molecules
attached to one glycerol molecule
• fatty acids consist of a chain of
hydrogen (H) and carbon (C)
atoms, with a few oxygen (O)
atoms
Triglycerides
some Triglycerides are a major
concern because of the type of
fatty acid they contain……...
fatty acids can be saturated or
unsaturated (monounsaturated
or polyunsaturated)
SATURATED FATS:
• chains containing the
maximum number of H
atoms
• solid at room temperature
- butter, lard etc., usually
animal fat
• associated with increased
cholesterol levels.
UNSATURATED
chains able to hold more H atoms
plant fats, usually liquid at room
temperature
if room for only 1 H atom =
monounsaturated
if room for more than 1 H atom =
polyunsaturated
both mono- and polyunsaturated
appear to lower total blood
cholesterol
Steroids (cholesterol):
essential in formation of:
• Vitamin D
• sex hormones (androgen,
estrogen and progesterone)
• protects nerve fibers
Lipoproteins
• transport mechanism
for cholesterol in blood
• three types of
lipoproteins
• HDL
• LDL
• VLDL
HDL (High Density Lipoproteins)
• transports circulating
cholesterol from blood to
liver for metabolism and
elimination from body
• the "good" cholesterol
• help protect against
coronary artery disease
LDL (Low Density Lipoproteins) and VLDL
(Very Low Density Lipoproteins)
• transport cholesterol
from digestive tract to
blood - "bad"
cholesterol
• associated with an
increase risk of
coronary artery
disease
Exercise HDL, LDL + VLDL, ratio of LDL/HDL
PROTEINS
• carbon (C), hydrogen (H),
oxygen (O), and nitrogen (N)
• essential for growth,
maintenance, and regulation of
body tissues and processes
• all living organisms contain
protein
• major component of all cells
• help build muscle, bone, skin,
and blood
Proteins
• major constituent of antibodies,
essential part of immune system
• aid in formation of hormones
such as insulin and thyroxin,
which regulate metabolism
• essential for enzyme formation
• high energy yield = 4 Kcal/g
• when CHO or Fat are insufficient,
protein can be used as an energy
source at expense of tissue growth
Proteins
• extra protein ingested will be broken
down to be used as calories or
converted into body fat
• proteins are formed from varying
combinations of 20 (21, 22 or 23)
amino acids
• amino acids are linked together in a
string and form proteins
• amino acids are linked in various
combinations to form various types of
proteins
Proteins
• body makes all but 8 amino
acids - called essential amino
acids must come from diet
(milk products, poultry, fish)
• animal protein contains
significant amounts of 8
essential amino acids, but also
contain saturated fat and
cholesterol
• any food containing all 8
essential amino acids is known
as complete protein
Proteins
• no source of vegetables or
cereal protein provides all 8
essential amino acids
• 3 combinations of incomplete
protein which make complete
protein
1. grains and legumes
2. grains and milk products
3. seeds and legumes
Protein
Ways to ensure adequate protein
intake………...
eat a varied diet containing all
three nutrients: proteins,
carbohydrates and fat; if
insufficient kcal from
carbohydrates and fat = body
uses proteins….
AND How Much Protein Should I
Eat??????
Are YOU Eating Enough protein?
Years Sex
16-18 M
F
>19
M
F
protein
(g/kg body wt)
0.88
0.81
Athletes
1.5 g/kg body wt
0.82
0.74
Adult male of 70 kg (above 19 years) should eat
70 X 0.82 or 57.4 g/day
2 glasses of milk
2 eggs
4 ounces of meat
Canadians eat approximately 90 g/day 2 X RDA
*** excess stored as fat or used as energy
VITAMINS, MINERALS, WATER
VITAMINS
• complex organic substances found in
food, or chemically made, that are
essential in small amounts for bodily
processes
• no difference found in food or
chemically made
• do not provide energy but play a role
in metabolism
• deficiency diseases result when
inadequate amounts are consumed
Grouped According to Solubility
Water Soluble
not stored in the body,
need to be replaced daily
These are……….
B-group and Vitamin C
Fat Soluble Vitamins……….
stored in the body and
can reach toxic levels if
consumed in megadoses
(many times the RNI)
Recommended Nutrient
Intake
Vitamins A, D, E, K
can act as antioxidants
– may slow down the
destruction of cells
MINERALS
• inorganic elements essential
for body function/regulation
components of hormones
/enzymes
• function with vitamin
absorption
• their potency can be
destroyed by various means
- heat, baking soda, etc.
Two Groups of Minerals
Macro-minerals < 5 grams
required in relatively large
amounts - (calcium,
magnesium, sodium,
potassium, phosphorus,
sulfur,chlorine)
Trace minerals > 5 grams
required in small amounts
(iron, zinc, manganese,
copper,iodine, colbolt)
WATER
• most important nutrient of all
• cannot survive for more than
a few days without water, but
can without other foods
• dehydration can result within
hours and can be fatal
• water carries nutrients to
cells, removes waste, and
regulates body temperature
• about two-thirds of body mass
is water
H2O and You
• females have about 50% as water
and males 60%, due to storage of
water in active tissue
• - males have greater muscle mass
• requirements for water intake
daily vary - 6 to 10 cups depending on environment and
activity levels
H2O
• water lost through
urination,
perspiration,
breathing
• 5% loss could result
in fatigue, loss of
concentration
physical ability
• 15% loss could result
in death
OPTIMAL NUTRITION THROUGH FOOD CHOICES
proportion of CHO, protein and fat
is essential. Current percentage of
calories from different nutrients is,
for the average Canadian, not in
the appropriate "balance”
basic dietary guidelines should be
considered
fat <30%
protein about 12%
CHO about 58%
A Balanced Diet….. HOW?
• one way to achieve balanced
diet is to consider the
number of daily servings of
each of the four basic food
groups
• lifestyle of the average
college student today and
the impact of "fast foods".
• fast foods are excessively
high in sodium, fat, simple
CHO and calories
Normal Eating vs. A Diet
• potential for the
development of certain
problems
• too much sodium relates to water
retention = high blood
pressure
• inadequate intake of
vitamins and minerals
• excess caloric intake,
etc.
NUTRITION AND THE CONSUMER
Be aware of food additives
- used to:
• maintain or enhance
nutritional value
• help in processing or
preparation
• maintain freshness
• make food more appealing
Labeling: Usually two kinds of info:
• nutritional info. per
serving i.e. serving
size, calories per
serving; protein, fat
and CHO per
serving;
• percentage of RDA.
VEGETARIANS
• obtain majority of nutrients from
plant sources
• may be vegetarian: vegetables +
legumes only
• lacto-vegetarian: eat vegetables +
legumes plus milk products
• lacto-ovo-vegetarian: vegetables +
legumes, milk plus eggs
• each of above presents different
challenge in terms of receiving all the
RDA of nutrients required
VEGETARIANS………….
• specifically vitamins D,
B12 and riboflavin can
be a problem. Also, zinc,
calcium and iron may be
difficult to include
• lack of calories for
children vegetarians can
be a problem
ATHLETES:
• optimal performance
sound nutritional status
• information and
misinformation relates to
athletic nutrition
• protein needs - usually too
much is consumed in the
mistaken belief that
• since muscles are made of
protein then high protein
diets will help build muscle
Athletes
• CHO - energy for
performance is essential.
Should be primarily
coming from complex CHO
• 60-70% CHO, 15%
protein, 25-30% fat
• important to replenish
within two hours for
optimal glycogen synthesis
STRESS
• generally agreed that diet is
related to stress. Foods can
produce stress response e.g.
caffeine = pseudo-stressors
•
Stress can impact to deplete
certain nutrients, such as
Vitamin C
• poor nutrition can result in
greater susceptibility to the
effects of stress
DEVELOPMENTAL ISSUES
• Nutritional needs change
throughout the life span
• importance of adequate diet for
pregnant women
• requirements for infants &
children
• reduction in caloric need with
increasing age