Home - Ec Chapter 4 - NUTRITION Flashcards
Food
Food is any solid or liquid that provides the body with nutrients. Food is any solid or liquid that provides the body with nutrients.
Nutrition
Nutrition is the study of food, the nutrients it contains and how they are used by
the body
Nutrients
Nutrients: These are chemical substances that make up
food. When digested, they allow the body to function
properly.
Elemental Composition
Elemental composition: Elements are individual
chemicals. The composition of something is the
elements that it is made up of. For example, protein is
made up of the elements carbon (C), hydrogen (H), oxygen
(O) and nitrogen (N).
Classification
Classification: This is a way of grouping similar things together. For
example, proteins are classified as high biological value proteins or low
biological value proteins
Source
Source: This is a food or something else that provides nutrients to the body.
For example, milk is a source of calcium and sunlight is a source of vitamin D.
Reference Intake
Reference Intake (RI): This is the average daily intake of a nutrient that is
needed to meet the nutritional requirements of the majority of people in
a specific age or gender group. For example, teenage girls have an RI of 15
mg of iron per day.
Function
Functions: These are the jobs a nutrient carries out in the body. For
example, carbohydrates provide the body with heat and energy
Food has six constituents. Five are nutrients
- Protein
- Fat
- Carbohydrates
- Minerals
- Vitamins
- Water
Nutrients are classified into 2 group
-MACRONUTRIENTS
- MICRONUTRIENTS
Macronutrients are required in LARGE amounts and are Protein, Fat &
Carbohydrates
Micronutrients are required in SMALL amounts and are vitamins & minerals
Composition of Protein
Protein is made up of four elements.
1. Carbon (C)
2. Hydrogen (H)
3. Oxygen (O)
4. Nitrogen (N)
Protein is the only nutrient that contains nitrogen (N). This element is
needed for the growth and repair of every cell in the body.
Compostion of protein cont
Chain of small units called amino acids.Amino acids are linked together with peptide links.
diagram:line with triangle,pentagon,square,circle
Classification of protein
- High biological value (HBV) proteins: These are proteins that contain ALL
or most of the essential amino acids needed by the body.
**Essential amino acids are those the body cannot make itself, so they
must come from food. Most HBV proteins are found in animal sources, e.g.
meat. - Low biological value (LBV) proteins: These are proteins that CONTAIN
SOME essential amino acids and usually come from plant sources, e.g.
cereals.
Sources of protein
HBV:meat,fish,eggs,milk,cheese,soya
LBV:pulses,cereals and nuts
Reference Intake of Protein
Adults need at least 50 g of protein, or approximately
0.75 g for every 1 kg of body weight.
• Children and teenagers need more because they are
growing so quickly
Functions of Protein
Protein is needed for the growth and repair of all body
cells (skin, blood, tissues and bones).
• It is necessary for the production of hormones,
enzymes and antibodies (which fight disease
Protein deficiency symptoms
poor or stunted growth with muscle wasting
• slow healing of wounds
• hair breakage and loss
• poor general health
• hormone and enzyme imbalances.
More severe protein deficiency occurs in developing countries such as Africa,
Asia, South America
- Marasmus
- Kwashikor
Composition of fats
Fats, also called lipids, can be in solid or liquid form. Liquid fats are called oils.
Fats are made up of three elements.
1. Carbon (C)
2. Hydrogen (H)
3. Oxygen (O)
Fats contain twice as much carbon as protein or carbohydrates, and therefore
produce twice as much energy
Composition of Fats cont
E shape-oval glycerol,3 sides coming out fatty acids
Classification of fats
- Saturated fat contains cholesterol – a type of fat found
in the blood. Saturated fat is generally found in foods that
come from animals. - Unsaturated fat does not contain cholesterol. It is found
in foods that come from vegetable or plant sources and in
oily fish.
Sources of Fats
Saturated:butter,cream,eggs,pastries
unsaturated:Avacadoes,nuts,seeds,olives,oily fish
Reference Intake of Fats
An average adult should not consume more than 70 g of fat per day. No more
than 20 g of this fat should be saturated.
Functions of Fat
Fats produce heat and energy.
• Adipose tissue (a layer of fat stored under the skin) helps to keep the body
warm.
• A layer of fat surrounds vital organs, such as the liver and kidneys, to protect
them from damage.
• Fats are a source of the fat-soluble vitamins A, D, E and K
Overconsumption of fats
- Obesity: Fats are all high in kilocalories. Eating too much fat causes weight
gain and obesity. ( think back to our discussion on Energy Balance) - Coronary heart disease: Too much cholesterol in the blood causes it to stick
to the artery walls, increasing the risk of heart attacks.
Reducing Fats in the Diet
Limit high-fat foods, such as takeaways.
• Use low-fat cooking methods (e.g. grilling,
steaming or baking) instead of frying.
• Modify recipes to reduce fat content, e.g. use
olive oil instead of butter for frying.
• Choose low-fat, fresh, unprocessed meats. Trim
any visible fat from meat before cooking.
• Choose low-fat products, e.g. low-fat cheese,
low-fat yoghurt.
• Always read food labels to check fat content
(particularly saturated fats)
Composition of Carbohydraytes
Carbohydrates are made up of three elements.
1. Carbon (C)
2. Hydrogen (H)
3. Oxygen (O)
These elements combine to form simple sugars, e.g. glucose.
These simple sugars link or combine together to
form long chains of starch.
During digestion, these long chains are broken down
by enzymes into simple sugars so that they can be
used by the body[pentagons on line]
Classification of Carbohydrates
- Sugar
- Starch
- Dietary fibre
Sources of Carbohydrates
Sugar:honey,cakes,jam,buscuits
Starch:cereals,breads,pasta
Dietry Fibre:Whole cereals,fruit and veg with skin
Functions of Carbohydrates
Heat and energy.
• Excess carbohydrates are stored as fat (adipose tissue),
which insulates the body.
• Dietary fibre is vital for the movement of waste through
the intestines, prevents constipation and helps prevent
diseases of the bowel, e.g. bowel cance
Dietry fibre names
Roughagee or cellulose
Increasing Fibre in the diet
Avoid refined carbohydrate foods.
• Eat wholegrain carbohydrates instead, e.g. brown bread instead of white.
Choose high-fibre breakfast cereals, e.g. porridge or bran flakes.
• Eat plenty of raw fruit and vegetables, with skins on where possible.
• Eat nuts or dried fruits, e.g. raisins, apricots or prunes.
Reference Intake (RI) for carbohydrates
It is recommended that we consume between 25 and 35 g of
fibre per day
Classification of minerals
Minerals are micronutrients that are vital for healthy body function. Macrominerals (calcium, sodium, phosphorus and potassium) are needed in
large amounts.
• Trace minerals (iron, fluoride, iodine and zinc) are needed in small amounts
Macromineral Calcium
SOURCES
• Milk
• Cheese
• Yoghurt
• Tinned fish, e.g. salmon (when bones
are eaten)
• Green vegetables, e.g. spinach
• Fortified products, e.g. cereals, bread,
flour
Functions of Calcium
Calcium builds strong healthy bones and teeth in
children and teenagers.
• It maintains good bone density (hardness) in adults
and older people.
Calcium deficiency diseases
Rickets,Osteoporosis
Reference Intake for calcium
Children and Adults:800 mg per day
teenagers and pregnant women:1,200 mg per day
Trace mineral
- iron
Sources
• Red meat
• Offal
• Eggs
• Fortified breakfast cereals
• Beans and lentils
• Dark green vegetables, e.g. kale
Functions of Iron
Iron is needed to manufacture haemoglobin. This is a substance in red blood
cells that is needed to carry oxygen around the body in the blood.
Iron deficiency diseases
Anaemia is a condition caused by lack
of iron. -The symptoms of anaemia
include tiredness, dizziness, paleness,
shortness of breath and headaches. -Women and teenage girls need to be
particularly careful to have enough iron
in the diet because of blood loss during
menstruation
Reference intake for Iron
Children:10mg per day
Teenagers:14mg per day
Adults:10mg per day
Pregnant:15mg per day
Sodium
Sodium is required to help control water balance in the body.
-Sodium is often called salt, but salt is actually a mixture
of sodium and chloride.
-It is recommended that adults consume no more than 6 g of salt
per day.
-Many people in Ireland consume too much salt, which can lead
to high blood pressure, coronary heart disease, strokes and
kidney problems.
( IFSA report found on average Irish adults consume 10g of salt/ day)
