Chapter 4 Flashcards
What are nutrients?
Nutrients are chemical substances that make up food. When digested, they allow the body to function properly
What is 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)
What is 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
What is a 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
What is reference intake?
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
What are functions?
These are the jobs a nutrient carries out in the body. For example; carbohydrates provide the body with heat and energy
What are deficiency diseases?
These are diseases that occur when the body is lacking a particular nutrient over a period of time. For example: scurvy is a disease resulting from a lack of Vitamin C
What are the nutrients?
Food has six constituents. Five are nutrients. The sixth is water, which while not a nutrient is vital for the body to function properly
1. Protein
2. Fat
3. Carbohydrates
4. Minerals
5. Vitamins
6. Water
What are constituents?
Constituents are the parts of something that come together to form the whole thing
What is food?
Food is any solid or liquid that provides the body with nutrients. Nutrition is the study of food, the nutrients it contains and how they are used by the body.
According to the world health organisation (WHO) ‘good nutrition- an adequate, well balanced diet combined with regular physical activity- is a cornerstone of good health’
What is the classification of nutrients?
Nutrients are classified into two groups:
1. Macronutrients: These nutrients are needed in large amounts and must be digested to be used by the body. The macronutrients are protein, fat and carbohydrates
2. Micronutrients: these nutrients are needed in small amounts and do not need to be digested. The micronutrients are mineral and vitamins
What is the composition of protein?
Protein is made up of four elements.
1. Carbon
2. Hydrogen
3. Oxygen
4. Nitrogen
Protein is the only nutrient that contains nitrogen (N). This element is needed for the growth and repair of every cell in the body
Protein is made up of a chain of smaller units called amino acids. Amino acids are linked together by peptide links.
Enzymes are substances that help chemical reactions. During digestion, enzymes break down amino acids
What is the classification of protein?
There are two types of protein:
1. 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 eg: meat
2. Low biological Value (LBV) proteins: these are proteins that do not contain many essential Amino acids and usually come from plant sources eg: cereals
What are the HBV Protein foods (animal origin and meat alternative) sources
• meat • Fish • Eggs • Cheese • Milk •Yoghurt • Soya beans
• Meat alternatives (textured vegetable protein and mycoprotein)
What are the LBV protein foods (vegetable origin) sources?
• Peas • Nuts • Beans • Lentils • Cereals
What is the reference intake for protein?
Adults need at least 50g of protein, or approximately 0.75g for every 1kg of body weight. Children and teenagers need more because they are growing so quickly
What are the functions of protein?
• Protein is needed for the growth and repair of all body cells (skin, blood, tissues and bones)
• It produces heat and energy
• it is necessary for the production of important substances in the body eg; hormones, enzymes and antibodies (which fight disease)
What are the protein deficiency symptoms?
Protein deficiency symptoms include:
• poor or stunted growth with muscle wasting
• Slow healing of wounds
• Hair breakage and loss
• Poor general health
• Hormone and enzyme imbalances
What is the 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
Each fat unit is made up of three fatty acids and one glycerol molecule
During digestion these are separated so that they can be used by the body
What is the classification of fats?
There are two types of fat:
1. Saturated fat contains cholesterol – a type of fat found in the blood. Saturated fat is generally found in foods that come from animals
2. Unsaturated fat does not contain cholesterol. It is found in foods that come from vegetable or plant sources and in oily fish
What are the sources of saturated fats?
• Butter • Cream • Cheese • Fatty meats
• Hard margarines • Pastries • Cakes
• Biscuits • Eggs • Coconut oil
What are the sources of unsaturated fats?
• Avocados • Nuts • seeds • oily fish
• Vegetable oils eg: olive oil
• Some soft margarines eg; flora
What are omega-3 fats
Omega-3 fats are a type of unsaturated fat found in oily fish, nuts and seeds. They are important for brain development and also help to lower blood cholesterol levels
What is the reference intake for fats?
An average adult should not consume more than 70g of fat per day. No more than 20g of this fat should be saturated.
No more than 30% of your daily energy intake should be from fats. It is better to get energy from carbohydrates and lean protein foods
What are the functions of fats?
• 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
What happens with the overconsumption of fats?
There are two main health problems associated with having too much fat in the diet:
1. Obesity: Fats are all high in kilocalories. Eating too much fat causes weight gain and obesity
2. Coronary heart disease: Too much cholesterol in the blood causes it to stick to the artery walls, increasing the risk of heart attacks
How do you reduce fat in the diet?
• Limit high-fat foods such as takeaways
• Use low-fat cooking methods (eg; grilling, steaming or baking) instead of frying
• Modify recipes to reduce fat content eg: 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 eg: low-fat cheese, low-fat yoghurt
• Always read food labels to check fat content (particularly saturated fats)
What is the composition of carbohydrates?
Carbohydrates are made up of three elements:
1. Carbon (C)
2. Hydrogen (H)
3. Oxygen (O)
These elements combine to form simple sugars eg: 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
What is the classification of carbohydrates?
Carbohydrates come from three different groups:
1. Sugar
2. Starch
3. Dietary fibre
What are the sources of sugar carbohydrates?
• Table sugar • Sweets • Honey • Cakes
• Soft drinks • Ketchup • Biscuits • Jam
• Fruit
What are the sources of starch carbohydrates?
• Cereals eg; wheat rice • Bread • Pasta
• Flour • Potatoes
What are the sources of dietary fibre carbohydrates?
• Whole cereals • Wholemeal bread
• Fruit and vegetables (particularly when the skins are eaten)
What are the functions of carbohydrates?
• Carbohydrates supply most of the body’s 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 eg; bowel cancer
What is sugar?
Sugar is a form of carbohydrate that can be called many different names eg; glucose, fructose, sucrose and maltose. Too much sugar in the diet can cause obesity and dental decay
High-sugar foods – Such as cakes, biscuits and fizzy drinks – are called empty calorie foods as they provide kilocalories but few other nutrients. These foods should be avoided.
Many foods eg: ketchup have hidden sugars. They may not taste sweet but are very high in sugar. Always examine packaging for hidden sugar – they may be listed as glucose, fructose, sucrose honey or treacle
How do you reduce sugar intake?
• Replace sugary snacks with nuts and fresh fruit
• Avoid sugar drinks. Water is much better.
• Avoid sweets, cakes, biscuits and desserts
• Use artificial sweeteners eg; Splenda or Canderel, instead of table sugar for baking and sweetening hot drinks
What is dietary fibre?
Dietary fibre is also called roughage or cellulose. Fibre is found in unprocessed foods, such as wholegrain cereals and fresh fruit and vegetables. Fibre helps to prevent constipation and other diseases of the bowel such as cancer
Fibre is not digested by the body. Instead it absorbs water as it passes through the digestive system, bulking up waste and allowing it to pass though the intestine more easily
How do you increase fibre in the diet?
• Avoid refined carbohydrate foods. Eat wholegrain carbohydrates instead, eg: brown bread instead of white. Choose high-fibre breakfast cereals eg; porridge or bran flakes
• Eat plenty of raw fruit and vegetables with skins on where possible
• Eat nuts or dried fruits eg: raisins, apricots or prunes
What is the reference intake for carbohydrates?
It is recommended that we consume between 25 and 35 g of fibre per day
What is the classification of minerals?
Minerals are macronutrients that are vital for healthy body function. Minerals are classified into two groups:
• Macrominerals: (calcium, sodium, phosphorus and potassium) are needed in large amounts
• Trace minerals: (iron, fluoride, iodine and zinc) are needed in small amounts
Both types of minerals are equally important for healthy body function
What are the sources of calcium
• Milk
• Cheese
• Yoghurt
• Tinned fish, eg: salmon (when bones are eaten)
• Green vegetables eg; spinach
• Fortified products eg: cereals, bread, flour
What are the 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
What are the calcium deficiency diseases?
Rickets: there are problems with bone formation when there is a lack of calcium and/or vitamin D in the diet. Bones do not harden properly during childhood, causing bow legs, a deformed spine and frequent fractures
Osteoporosis: this is a bone disease that causes bones to become weak. As we age, bones naturally begin to lose calcium. This process occurs rapidly in people who have had low intakes of calcium in their diets over the years. Osteoporosis is more common in women. The symptoms of osteoporosis are: porous, fragile bones that fracture easily. Osteoporosis cannot be cured, but it can be prevented by eating foods containing calcium and vitamin D throughout life, taking regular, weight-bearing exercise and avoiding smoking
What is the reference intake for calcium?
The reference intake for calcium for children and adults is: 800mg per day
The reference intake for calcium teens and pregnant/breastfeeding women is: 1200mg per day
What are the sources of iron?
• Red meat
• Offal
• Eggs
• Fortified breakfast cereals
• Beans and lentils
• Dark green vegetables eg: kale
What are the 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
What are the 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. Woman and teenage girls need to be particularly careful to have enough iron in the diet because of blood loss during menstruation
What is the reference intake for iron?
The reference intake of iron for children is: 10mg per day
The reference intake of iron for teens is: 14mg per day
The reference intake of iron for adults is: 10mg per day
The reference intake of iron for pregnant/breastfeeding woman is: 15mg per day
What is 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 6g 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
How do you reduce salt intake?
• Do not have salt on the table
• Do not add salt when cooking: instead flavour dishes with spices and herbs
• Avoid processed foods and salty snacks eg: cured meats
• Use low sodium products eg: LoSalt
What is the classification of vitamins?
Vitamins are classified into two groups;
• Fat soluble vitamins (A, D, E, and K) are stored in the body
• Water soluble vitamins (B group and C) cannot be stored by the body and need to be eaten every day
What are the sources of vitamin A?
• Pure vitamin A: found in Animal sources eg: oily fish, eggs, butter
• Carotene/provitamin A: A substance found in highly coloured vegetables (eg: carrots, peppers, dark green vegetables) that the body converts to vitamin A
What are the functions of vitamin A?
• Good eyesight
• Healthy linings of nose, mouth and throat
• Growth
• Healthy eyes skin and hair
What are the deficiencies of vitamin A?
• Night blindness
• Linings of nose, mouth and throat become dry and irritated
• Delayed growth
• Dry, patchy skin
What are the sources of vitamin D?
• Sunshine
• Oily fish, fish liver oils, tinned fish eg: sardines, cheese, butter, eggs, margarine
What are the sources of vitamin E?
• Seeds, nuts, cereals
What are the sources of vitamin K
• Green vegetables milk and cheese
• Made by the healthy bacteria in the intestines
What are the functions of vitamin D?
• Works with calcium for healthy bones and teeth
What are the functions of vitamin E?
• Protects against heart disease
• Healthy skin
What are the functions of vitamin K?
• Essential for normal blood clotting
What are the deficiency diseases of Vitamin D?
• Rickets
• Tooth decay
• Osteoporosis
• Osteomalacia (adult form of rickets)
What are the deficiencies of vitamin E?
• Deficiencies are rare
What are the deficiencies of vitamin K?
• Blood will not clot normally (very rare)
What is Hypervitaminosis?
As fat soluble vitamins are stored in the fatty tissue of the body, supplies can build up to toxic levels. This is called Hypervitaminosis and normally occurs when people overuse vitamin supplements. Hypervitaminosis A and D are most common
What are the sources of vitamin B?
• Meat
• Eggs
• Fortified cereal
What are the sources of folate (or folic) acid?
• Wholemeal bread
• Fortified products eg: cereals
• Vitamin Supplements
What are the sources of vitamin C?
• Fruits: blackcurrants, kiwis, oranges, lemons, strawberries
• Vegetables: peppers, broccoli, tomatoes, peas, kale
What are the functions of vitamin B?
• Controlling the energy released from foods
• Healthy nervous system
What are the functions of folate (or folic) acid?
• Taking folic acid before and during pregnancy reduces the risk of neural tube defects in unborn babies
What are the functions of vitamin E?
• Good general health
• Healthy gyms, skin and blood vessels
• Healing of wounds
• Helps absorption of iron in the body
What are the deficiencies of vitamin B?
• Delayed growth
• Tiredness
• Beriberi (a serious nerve disease)
• Pellagra (a disease that affects the skin, causes diarrhoea and dementia and often results in death)
What are the deficiencies of Folate (or folic) acid?
• Neural tube defects eg: Spina bifida (bones of the spine do not close over properly causing injury to the spinal cord)
What are the deficiencies of vitamin C?
• Increased risk of colds and flu
• Scurvy (a disease that causes tiredness, muscle weakness, aching joints and bleeding gums)
• Delayed healing of wounds
• Anaemia (because iron is not absorbed properly)
How much water do we lose each day?
Water is essential for all life. Our bodies are 70% water. Each day we lose approx 2-2.5 litres through perspiration (the production of sweat to cool down the body) and urination. This water needs to be replaced. While we get some water from the foods we eat, it is important to drink plenty of fluids: 2 litres or eight glasses of water per day is recommended
What is the composition of water?
Each water molecule contains the elements Hydrogen (H) and Oxygen (O) in a 2.1 ratio. Water is represented by the formula H20
What are the properties of water?
• Water boils at 100C and freezes at 0C
• Water can be solid (ice) liquid (water) or gas (vapour)
• Pure water is tasteless, colourless and odourless
• Some substances dissolves easily in water, eg: salt (making brine) and sugar
What are the sources of water?
• Food: Most foods contain water, apart from fats and dried foods eg: flour and sugar
• Drinks: water, milk, juices, tea and coffee
What are the functions of water?
• Water is an essential part of all body tissues and fluids eg: blood
• It transports nutrients and oxygen to al body cells
• It helps to remove waste products from the body through urine
• Water regulates body temperature through perspiration (sweat)
What is dehydration?
Dehydration occurs when the body loses more water than it takes in. This is common after a period of vomiting or diarrhoea or if too much alcohol is consumed. Symptoms of dehydration include: a dry mouth, bad breath, headache, low blood pressure and dizziness. Dehydration is particularly dangerous in babies and older people
