[L3 Principles of Nutrition] Section 1: Key guidelines of nutrition Flashcards
Define nutrition
The delivery of essential materials (required to promote
optimal health and growth) to cells and organisms.
Deine Diet
Current eating pattern.
What are the functions of macronutrients?
Used within the body for structure, function, and fuel.
What are the functions of micronutrients?
Used for:
- Structure
- Function
- Are necessary to ‘unlock’ the energy contained within the macronutrients.
- Support and manage vital physiological processes within the body.
How many amino acids are there?
20
The basic structure of a protein is what?
A chain of amino acids?
Most proteins are relatively large molecules comprised of at least how many amino acids?
100
Smaller clusters of amino acids are referred to as what?
Peptides
Name the four types of peptides and state the number of amino acids in each
Dipeptide = 2 Tripeptide = 3 Oligopeptide = 4-9 Polypeptide = 10+
Protein makes up what percentage of the body?
18-20%
What are the three groups of amino acids?
- Essential,
- Non-essential
- Conditionally essential
What are essential amino acids and how many are there?
There are 9 essential amino acids and they are considered to be essential to the daily diet because the body is unable to produce or synthesise them itself
What are ‘non-essential’ amino acids?
These are made by the body from essential amino acids or in the normal breakdown of proteins.
What are ‘conditionally essential’ amino acids?
These are amino acids that be synthesised by the liver if the 9 essential amino acids are absorbed, but for certain population groups, these amino acids must be supplied by the diet to ensure good health.
What is a ‘complete’ protein source
These foods contain all nine essential amino acids in sufficient amounts necessary for the liver to synthesise
the remaining non-essential amino acids.
What is an ‘incomplete’ protein source
These proteins are considered to have a lower biological value since they are usually lacking one or
more of the essential amino acids. e.g. plants
What is a ‘complementary’ protein source
Carbohydrate-based foods that also contain smaller
amounts of protein.
What are the 6 functions of protein?
- They serve as enzymatic catalysts.
- They are used as transport molecules (haemoglobin transports oxygen) and storage molecules (iron is stored in the liver as a complex with the protein ferritin).
- They are used in movement (proteins are the major component of muscles).
- They are needed for mechanical support (skin and bone contain collagen, which is a fibrous protein).
- They mediate cell responses (rhodopsin is a protein in the eye which is used for vision).
- Antibody proteins are needed for immune protection.
What are the three categories of protein functions?
Structural, Homeostatic, and Fuel proteins
What are structural proteins?
Proteins that form the main framework of many components of the body.
Proteins are present in collagen in bone and connective tissue, keratin in the skin, and in muscle
tissue.
What are Homeostatic proteins?
Proteins that make up hormones that regulate various processes, e.g. insulin controls blood sugar, enzymes speed up reactions, and white blood cells fight infection.
What are Fuel proteins?
Proteins that are used as a source of energy
- Especially during endurance events or periods of fasting. They can be converted into glucose, fatty acids, or ketones to help produce adenosine triphosphate (ATP).
What is anabolism?
The set of metabolic pathways that construct molecules from smaller units.
When does the anabolic phase mostly orrcur?
During rest
What is catabolism?
The set of metabolic pathways that break down
molecules into smaller units and release energy.
What happens to molecules during catabolism?
Large molecules (e.g. polysaccharides, fatty acids, nucleic acid, and proteins) are broken down into smaller units (e.g. monosaccharides, fatty acids, nucleotides, and amino acids) during processes such as respiration and digestion
Why are carbohydrates an ideal source of energy for the body?
Because they can be converted more easily (than proteins or fats) into glucose
A diet too high in carbohydrates can upset the balance of the body’s what?
Blood sugar level, resulting in fluctuations in energy
and mood.
What are the two ways Carbs are utilized in the body?
1) It is sent to the liver, to the muscles to be stored as glycogen, or used immediately
as a fuel.
2) Some glucose may also enter the adipose tissue (fat tissue) where it is used to help store fat.
All carbohydrates are made up of molecules or units called what?
Saccharides
Saccharides form the three basic carbohydrate types. What are they?
Simple Carbs (Sugar) Complex Carbs (Starch) Non-Starch Polysaccharides (Fibre)
What is the basic unit of carbohydrates?
A single sugar molecule/A monosaccharide
What are two sugar molecules called?
Disaccharide
Monosaccharides and disaccharides are categorised as what?
Simple sugars/Simple Carbs
Simple carbohydrates are typically a combination of what molecules?
Glucose, fructose and galactose.
The energy contained in simple sugars/carbs can’t be released without specific what?
Vitamins and minerals.
The B vitamins are particularly important because the body can’t utilise carbohydrates without them.
Why B vitamins particularly important>
The body can’t utilise carbohydrates without them.
List the benefits of naturally-occurring sources of simple carbs (fruit)
- Contain fructose and glucose in varying amounts.
- Contain vitamins and minerals.
- Contain antioxidants and phytochemicals.
- Contain high levels of dietary fibre.
- Contain traces of amino acids.
- Cheap; convenient.
List the cons of processed food sources of simple carbs.
- Contain excessive sugar – higher than 15g per 100g (FSA).
- Contain processed, low-quality fats.
- High energy density.
- Contain no vitamins or minerals.
- Adversely affect insulin response.
What are refined carbs?
Contain excessive sugar (over 15g per 100g) Contain processed, low-quality fats Have high energy density No vitamins or minerals Adversely affect insulin response.
Examples:
white bread, white pasta, cakes, biscuits, pastries, white rice, rice cakes.
What are unrefined carbs?
Contain fructose and glucose in varying amounts Antioxidants and phytochemicals High levels of dietary fibre Vitamins and minerals Trace of amino acids.
Examples:
wholemeal or whole grain products, whole grain rice, frozen/fresh vegetables, pulses, quinoa.
What is the purpose of fibre?
Aids in the transportation of food through the digestive tract.
Where is insoluble fibre normally found, and what are some sources?
These are normally found on the outer protective layer of plants.
Unrefined wheat, bran, rye, rice and most other grains are primarily composed of insoluble fibre, as are fruit and vegetable skins.
Where is soluble fibre normally found, and what are some sources?
These are normally found in the inner parts of plants.
Sources include beans, barley, broccoli, prunes, apples, citrus fruits and oats.
How do soluble NSPs (fibres) help to reduce cholesterol?
By binding with fats in the digestive tract and carrying them out in the stools.
In order to provide energy, dietary CHO must first be converted to?
Glucose
Why do different sources of CHO raise blood glucose more rapidly?
Differing forms of CHO have different arrangements of molecules and so some are more quickly converted to glucose than others
What is the glycaemic index (GI)?
The glycaemic index (GI) provides an indication of the relative speed with which a food is converted to glucose and absorbed into the bloodstream.