2. FOOD IS ANY SUBSTANCE OF ANIMAL, VEGETAL OR MINERAL ORIGIN
THAT CAN BE USED AS A SOURCE OF NUTRIENTS
NUTRIENTS ARE CHEMICAL SUBSTANCES THAT HELP OUR BODY TO
STAY HEALTHY AND FULL OF ENERGY.
NUTRIENTS ARE CONTAINED IN FOOD
3. THE DIET IS WHAT YOU EAT AND DRINK.
YOU NEED TO HAVE A BALANCED DIET
FOR ENERGY, GROWTH, REPAIRING TISSUES, HEALTH OF YOUR BODY
WATER IS ESSENTIAL IN A BALANCED DIET.
4. FIVE TYPES OF NUTRIENTS:
(diet must contain all of them)
•CARBOHYDRATES
•PROTEINS
•FATS
•VITAMINS
•MINERAL SALTS
5. THOSE ARE NOT NUTRIENTS BUT ESSENTIAL IN THE DIET:
•WATER
•FIBERS
6. FUNCTIONS OF THE NUTRIENTS:
• ENERGETIC FUNCTION: to obtain energy to move and mantain the
temperature, thanks to carbohydrates, fats, and proteins. (ENERGY)
• PLASTIC FUNCTION: to create new body tissues with proteins, fats, minerals,
and water (GROWTH AND REPAIR).
• REGULATORY FUNCTION: regulate vital functions with proteins (especially a
type of protein, the hormones), minerals, vitamins and water. (HEALTH)
• PROTECTIVE FUNCTION: defends the body. Carried out by some proteins and
vitamins (HEALTH)
7. HOW DO WE MEASURE THE ENERGY FROM FOOD?
Most of the food we eat is transformed into energy…
• To measure energy we use the Joule (J) and the kiloJoule (kJ = 1000
Joules).
But the most used unit of measurement for food is the
KILOCALORIE (kcal)
(definition: the kilocalorie is the amount of heat required to raise the
tempeature of one kilogram of water by 1°C)
8. HOW DO WE MEASURE THE ENERGY FROM FOOD?
But the most used unit of measurement for food is the
KILOCALORIE (kcal)
11. CARBOHYDRATES
• In pasta, bread, pulses, cereals,
sweet foods, candy, cakes.
• Formed by C, H, O
• They can be short molecules (SUGARS) or
long molecules (POLYSACCHARIDES)
• SUGARS (ex. glucose, fructose, lactose etc.)
• POLYSACCHARIDES (ex. starch, cellulose)
12.
13.
14.
15.
16. CARBOHYDRATES
• The most important
sugar is GLUCOSE. It is
formed in the leaves of
green plants through
photosynthesis
A molecule of glucose and
a molecule of fructose
together form the
SUCROSE: it is the sugar we
normally use in the kitchen.
17. CARBOHYDRATES: STARCH
• The polysaccharide STARCH works as a reserve of nutrients in plants.
• It is contained in grains, bread, pasta, legumes, potatoes.
• It is formed by a long chain of glucose molecules. When we eat
starch, our digestive system breaks down the starch into glucose
molecules that are used as energy.
• If you chew bread for a long time,
it will taste SWEET!
Try it at home!
18. A special kind of carb we cannot digest…
• The polysaccharide CELLULOSE forms the rigid parts of the plant
(stems, leaves, fruit peel etc.). It has plastic function in the plants.
• Our digestive system cannot break it. Why is it useful?
19. A special kind of carb we cannot digest…
• Our digestive system cannot break it. Why is it useful? It forms
DIETARY FIBRE
• Fibre helps our digestive system in functioning, without blocking
(constipation), protects the intestine from tumours and prevents
cardiovascular diseases
• Pulses, wholegrain pasta,
wholegrain bread,
rice, bran etc.
are rich in fibers.
20. FATS (also called LIPIDS)
• FATS are the energy reserve of the human
body
• They are accumulated in the ADIPOSE TISSUE
• They also have plastic function: they form parts of
our body (for example: the membrane of all the cells
is formed by lipids!)
• Too much fat will cause problems in the circulatory
system, blocking the blood.
21. FATS (also called LIPIDS)
• FATS are the energy reserve of the human body
Animal fats: in butter, cheese, milk, fatty meat
Vegetable fats: in nuts, avocado, vegetable oils like olive oil
22. PROTEINS
The second most abundant substance in the body, after water
• ANIMAL PROTEINS in meat, fish, eggs, milk, cheese
• VEGETABLE PROTEINS in grains and pulses (legumes)
23. PROTEINS - AMINOACIDS
Proteins are made up by long chains of AMINOACIDS,
like a pearl necklace.
• 20 different types of aminoacids – like 20 different types of pearls
• We have millions of different types of proteins
• A different sequence in aminoacids forms a different protein
24. PROTEINS - AMINOACIDS
Proteins are made up by long chains of AMINOACIDS,
like a pearl necklace.
• 20 different types of aminoacids – like 20 different types of pearls
• We have millions of different types of proteins
• A different sequence in aminoacids forms a different protein
25. PROTEINS - AMINOACIDS
• 20 different types of aminoacids – like 20 different types of pearls
• We have millions of different types of proteins
• A different sequence in aminoacids forms a different protein
26. PROTEINS
Animal proteins have all the aminoacids that the body needs.
Vegetable proteins do not have all the aminoacids the body needs.
Therefore, I must eat a variety of vegetable food to have the
combination of all the aminoacids the body needs.
• Proteins have all the functions: energetic function, plastic function,
regulatory function and energetic function.
27. VITAMINS
• They help our body to grow, they
regulate cell processes and they protect
us from diseases
• They do not contain energy
• We need to take them from the diet (we
cannot create all of them in our body)
30. MINERAL SALTS
• Are inorganic substances in our
body, in solid form or dissolved in
water
• Example: Calcium, Phosphorous,
Magnesium, Potassium, Sodium,
Chlorine, Iron…
• Have protective and plastic function
(e.g. calcium in bones)
