Transcript feeding and nutrition

Unit 2:
Food and
health
UNIT OBJECTIVES
• To learn about nutrients and diet
• To learn about food-related illnesses
• To study food preservation methods and
product labelling
• To investigate how to prepare a balanced
diet
1. Nutrients and diet
• 1.1. Differences between feeding and
nutrition. Are they the same thing?
Eating or feeding
• It is a conscious, voluntary action and
depends on different factors:
• Economic, climatic, religious, etc.
Nutrition
• It is an involuntary, unconscious process.
• Through nutrition, nutrients enter the cells
to be absorbed and used in various
metabolic processes.
• Systems involved in nutrition?
• Digestive, respiratory, circulatory and
excretory system
Nutrients are substances that provides
nourishment essential for the maintenance of life
and for growth:
• Function of nutrients:
– Energetic: necessary energy to carry out vital
functions. Example?
– Structural: to form our body tissues. Ex?
– Regulating function: to control chemical
reactions in our organism: vitamin C
NUTRIENTS
• Energetic
– Glucose: this nutrient travels in the blood to the cells
and it is used by the mitochondria to obtain energy for
the cell
• Structural
-Proteins: provide the structure for cells, tissues and organs,
replace damaged structures and enable growth and repair
• Regulating
– Vitamin C (we cannot produce our own vitamines, we
must ingest them) (antioxidant, vision, synthesis of
collagen for vessels, tendons, ligaments and bones..)
Classification of nutrients
• Water
• Minerals: Structural and regulating functions
– i.e Phosforous: DNA, RNA, ATP, cellular membranes,
bones.
• Carbohydrates: Energetic function
– sugars and polysacharids
• Lipids: Energetic and structural function
– oil..energy stored in our adipose cells. Migratory birds
use stored energy of triacylglycerols to fuel their
flights
– Cell membranes
Classification of nutrients
• Proteins: many functions.e.g.
– Haemoglobin: transports oxygen to cells
– Enzymes, which catalyze chemical reactions:
amylase in our saliva, breaks up starch into
sugar
– Collagen (connective tissue as cartilage)
– Keratin: hair, nails…
– Actin and tubuline make up the cytoskeleton
Classification of nutrients
• Vitamins:
– vitamin A (retinol): vision (poor night vision)
– Vitamin C (ascorbic acid): protects cells from
aging, production of fibres in the body
(synthesis of collagen) (scurvy)
– Vitamin D (calciferol): D is needed for the
absorption of calcium. (rickets)
Food Wheel
• Food is classified into six groups:
– Group I: cereal and starches (carbohydrates)
– Group II: oils and butter (lipids)
– Group III: meat, egg, fish, nuts, legumes
(proteins)
– Group IV: milk and derivates (proteins,
vitamins, minerals)
– Group V: vegetables (vitamins and minerals)
– Group VI: fruits (vitamins and minerals)
Activities you must answer in
your notebook:
• Page 23: questions: 1, 2, 4 and 5
• Page 24: questions: 2 and 3
• Page 25:Work with the image:Questions 5,
6 and 8
• Page 27: questions 3, 4 and 6
• Page 28: questions 1, 2 and 3
• Page 30: questions 3 and 5
Page 26 The
energy value of food:
• When nutrients from food enter the cell we
use them as fuel to produce energy through
cellular respiration
Units of energy:
• The most common units are calories or
kilocalories
• Joule or kilojoule is the unit of energy in
the International System.
• 1 gram of carbohydrates has about 4 kcal
• 1 gram of lipids has 9 kcal
What is 1 kcal?
• The kilocalorie is approximately the
amount of energy needed to raise the
temperature of one kilogram of water by
one degree Celsius. (symbol: kcal)
Why is cellular respiration
important?
• Because nutrients are oxidized ( broken
down) in the mitochondria and energy is
produced from them.
• What by products does it produce?
Carbon dioxide and water
Daily energy needs
• Basal metabolic rate (BMR) is the rate of
energy expenditure at rest or the number
of calories you'd burn if you stayed
motionless for a day.
• Energy expenditure varies by sex and age
• BMR is higher when a person is growing and
lower when the person is older or has a low
body mass
Page 28
A healthy, balanced diet:
• What makes for a healthy diet?
• How do you know if you are eating a
balanced diet?
What makes for a healthy diet?
•
•
•
•
•
Eat a variety of different foods
Have 5 meals each day
Eat fresh vegetables
Avoid convenience foods
Eat fibre-rich foods daily
What is a diet?
• Diet consists of all the food a person
usually eats.
• Does the diet vary?
• Yes, it depends on each person´s physical
activities, daily routines, soft diet are used
if someone is suffering from a disease or
after surgical operation ( food such as rice,
chicken and fish is served, preferably
boiled).
Page 28,Healthy,
Balanced diet
• Diets should be balanced and contain
nutrients in the right amounts to guarantee
a healthy body.
• What are the recommendations for a
healthy diet?
• Carbohydrates?..............55-60%
• Lipids?............................30%
• Proteins?........................15%
Page 28 Mediterranean
Diet
• It is considered to be Balanced and
healthy.
• It incorporates the traditional healthy
eating habits found in southern Europe.
• It is based in the consumption
of olive oil, pulses, fish,
vegetables and fruit.
What are the health benefits
from the Mediterranean diet?
• It prevents cardiovascular diseases and
some cancers associated witth diet ( colon
cancer) and it´s less likely to lead to
obesity.
Page 30 FOOD
PRESERVATION
• Food preservation is the process of
treating and handling food to stop the loss
of quality, edibility or nutritive value
caused by microorganisms.
FOOD PRESERVATION
METHODS
• Cold preservation methods: to prevent the
growth of bacteria
» Perishable food lasts 5 days if kept 0º-4ºC in the
fridge
» Perishable food lasts several months
if kept under -20ºC inside the freezer
Page 30 FOOD
PRESERVATION
METHODS
• Heat preservation methods
– Applying high temperatures for a few
seconds. I.e. Pasteurisation (72ºC, cooling
down quickly).
Pasteurization: It is a process that
applies heat to destroy pathogens
• Sterilization: It requires temperatures
higher than 100 ºC.
FOOD PRESERVATION
METHODS
• Dehydration or drying:
– Eliminating water using high temperatures
• Dehydrated foods Advantages of this method?
Advantages of dehydration
• Reduces volume and weight, so products
are easier to manipulate, package and
transport.
Activities from Page 30
3.- What is the main purpose of all food preservation processes?
The main purpose of food preservation is to avoid the proliferation of
microorganisms and to prevent the food from deterioration.
Why is this necessary?
Because most food is perishable and it will be spoiled due to environmental and
biological factors.
5.-Give 3 examples of foods preserved by each of the 4 processes described
on page 30.
.- Examples of Foods that Are Commonly Pasteurized
Whole Eggs Removed from Shells and Sold As a Liquid, Today, many foods, such
as eggs, milk, juices, spices and ice are pasteurized.
.- Examples of foods preserved with sterilization: tuna tins.
.- Dehydration: Mushroom soup
.- Chemical preservation: Foods preserved by high sugar concentrations: jellies,
syrups, juice concentrates; Vinergar preservers cucumbers as pickles.
FOOD ADDITIVES
• Substances added to food to improve its
taste, preserve flavour, make it look more
attractive and prevent it from spoiling.
– Colourings: enhance natural colours to make
food look more attractive, or provide food with
an attractive colour (colorants)
Questions: What does the
following sentences refer to?
• The foods are subjected to temperatures
of above 100ºC…..Sterilization
• The foods are subjected to temperatures
between 0 and 4 ºC…Refrigeration
• The foods are subjected to temperatures
below -18ºC….. Freezing
• The water is removed from
foods….Dehydration.
Page 32. FOOD RELATED
ILLNESSES
• FOOD POISONING: ingestion of food
contaminated with microorganism or
chemicals
– Salmonellosis
Salmonella genus
FOOD RELATED ILLNESSES
• Food poisoning
– Botulism
Clostridium botulinum
Botulism is a rare but
serious paralytic illness
caused by a nerve toxin
that is produced by the
bacterium
FOOD RELATED ILLNESSES
• Salmonella
– Eggs, meat, milk,
touching infected
faeces
• Botulism
– Home canned food
substances.
- Anaerobic bacteria that
forms spores
Food allergies
• It refers to people who are sensitive to
substances in food called allergens and
react to them.
• E.g. Allergic to gluten ( protein in some
cereals) suffer from celiac disease.
Page 32 Q 2.- Give examples of 3 microorganisms that can cause food poisoning.
Page 33 Q 9.-Make a table of food-related illnesses.
Causes
Food poisoning
Food allergies
Eating disorders
Effects
Name of bacterium
Original source
Risky foods
Time to develop
Symptoms
Micro organisms that can cause
food poisoning
Bacillus cereus
soil
cooked rice and pasta; meat
1–5 hours
products; vegetables
nausea, sickness and
diarrhoea
Campylobacter jejuni
raw meat and poultry
undercooked meat and
poultry; raw milk and crosscontaminated food
fever, severe pain and
diarrhoea
Clostridium botulinum
(very rare)
soil
faulty processed canned
meat and vegetables; cured 1–7 days
meat and raw fish
affects vision, causes
paralysis and can be fatal
Clostridium perfringens
the environment
large joints of meat; reheated
8-24 hours
gravies
nausea, pain and diarrhoea
Escherichia coli
the gut of all humans and
E. coli O157:H7 is a very
animals
nasty strain it can be fatal
contaminated water, milk,
inadequately cooked meat,
cross-contaminated foods
3-4 days
inflammation, sickness and
diarrhoea
Listeria monocytogenes
everywhere
soft cheeses, paté, prepacked salad; cook-chill
products
varies
fever, headache, septicaemia
and meningitis
Salmonella
gut of birds and mammals
poultry, eggs and raw egg
including humans - spread by
products, vegetables
faeces into water and food
6-48 hours
diarrhoea, sickness and
headaches
Staphylococcus aureus
the skin and noses of
animals and humans
3–5 days of eating infected
food
cured meat; milk products;
2-6 hours
unrefrigerated, handled foods
sickness, pain and
sometimes diarrhoea
Food poisoning
Food allergies
Causes
Bacteria, viruses
Effects or consequences
Symptoms:

Nausea

Vomiting

Diarrhoea

Abdominal pain and
cramps

Fever
Your immune system in error identifies a
specific food or a substance in food as
something harmful.
Allergic responses: dripping
nose,
itchy eyes,
dry throat
, rashes and hives, nausea,
diarrhea,
labored breathing,
and even anaphylactic
shock.
Your immune system triggers cells to
release antibodies to neutralize the food
substance (the allergen).
The next time you eat even the smallest
amount of that food, antibodies sense it
and signal your immune system to release
a chemical called histamine, as well as
other chemicals, into your bloodstream.
Eating
disorders
Psychological and emotional health.
Low self-esteem,
perfectionism,
impulsive behavior
troubled relationships.
Society. Success is often fuel this desire
to be thin.
Abnormally slow heart
rate and low blood pressure.
Reduction of bone density
which results in brittle
bones.
Muscle loss and weakness.
Severe dehydration, which
can result in kidney failure.
Fainting, fatigue, and
overall weakness.
Dry hair and skin; hair loss
is common.
Page 32. FOOD RELATED
ILLNESSES
• Malnutrition: inadequate diet
– Undernutrition (insufficient food): includes
rickets, anorexia and bulimia
• RICKETS (raquitismo)
Lack of calcium
and phosporus
(vitamin D)
Deformities of the
bones
Activity round-up: Page 34
Questions 4: Define malnutrition, obesity, anorexia and bulimia.
Malnutrition is the condition that develops when the body does not get the right
amount of the vitamins, minerals, and other nutrients it needs to maintain healthy
tissues and organ function.
Obesity is an abnormal accumulation of body fat, usually 20% or more over an
individual's ideal body weight. Obesity is associated with increased risk of other
diseases such as diabetes and hypertension.
Anorexia is an eating disorder characterized by reduced appetite or total aversion
to food. Anorexia is a serious psychological disorder. The person with anorexia try to
lose weight by not eating. Therefore, they become extremely thin and weak.
Anorexia can cause serious health problems and can lead to death.
Bulimia is an eating disorder characterized by episodes of excessive eating
followed by inappropriate methods of weight control, such as self-induced vomiting ,
abuse of laxatives and diuretics.
Page 35. Interpret food labels.