Nutrition Chapter 4 Flashcards
Nutrients:
Nutrients: These are chemical substances that make up food. When digested, they allow the body to function properly.
Elements are individual
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 (0) 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.
Functions:
Functions: These are the jobs a nutrient carries out in the body. For example, carbohydrates provide the body with heat and energy.
Deficiency diseases:
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.
Nutrients
- Protein
- Minerals
- Fat
- Vitamins
- Carbohydrates
- Water
Classification of nutrients
Nutrient group
Explanation
Examples
Macronutrients
Needed in large amounts and must be digested to be used by the body
• Protein • Carbohydrates
• Fat
Micronutrients
Needed in small amounts, and do not need to be digested
• Minerals
• Vitamins
Composition of protein
Protein is composed of carbon, oxygen, hydrogen, and nitrogen. Nitrogen is essential for cell growth and repair. Amino acids linked by peptide bonds make up proteins, broken down by enzymes during digestion.
Classification of protein
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. Most HBV proteins are found in animal sources, e.g. meat.
2. Low biological value (LBV) proteins: These are proteins that do not contain many essential amino acids and usually come from plant sources, e.g. cereals.
Sources of protein
HBV protein foods
(animal origin and meat alternatives)
• Meat
• Fish
• Eggs
• Cheese
• Milk
• Yoghurt
LBV protein foods (vegetable origin)
• Peas
• Beans
• Lentils
• Nuts
• Cereals
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.
Protein deficiency symptoms
• slow healing of wounds
• hair breakage and loss
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 (0)
Each fat unit is made up of three fatty acids and one glycerol molecule.
During digestion, enzymes break down the links between the fatty acids and glycerol molecule so that they can be used by the body.
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.
suture
2. 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 fat
• Butter
• Cream
• Cheese
• Fatty meats
• Hard margarines
• Pastries, cakes and biscuits
• Eggs
• Coconut oil
• Avocados
• Nuts
• Vegetable Oils, e.g. olive oil
Unsaturated fat
• Seeds
• Some soft margarines, e.g. Flora
• Oily fish
Functions of fats
• Fats produce heat and energy.
• A layer of fat surrounds vital organs,
Functions of fats
• Fats produce heat and energy.
• A layer of fat surrounds vital organs,
Composition of carbohydrates
Carbohydrates consist of carbon, hydrogen, and oxygen. These elements form simple sugars like glucose, which further combine into starch chains. Enzymes break down starch into glucose for body use during digestion.
Classification of carbohydrates
Carbohydrates come from three different groups.
1. Sugar
2. Starch
•60%
3. Dietary fibre
Sources of carbohydrates
Sugar
Starch
Dietary fibre
• Table sugar
• Sweets
• Cereals, e.g. wheat, rice
• Whole cereals
• Honey
• Soft drinks
• Bread
• Wholemeal bread
• Cakes
• Ketchup
• Pasta
• Fruit and vegetables
• Biscuits
• Fruit
• Flour
(particularly when the
• Jam
• Potatoes
skins are eaten)
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, e.g. bowel cancer.
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.
Functions of fibre
• Fibre absorbs water as it passes through the digestive system, bulking up waste and allowing it to pass through the intestine more easily to prevent constipation.
• Fibre helps to prevent diseases of the bowel, such as bowel cancer.
