[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.
Fats and oils are often referred to as lipids. Lipids that are liquid at room temperature are called?
Oils
Fats and oils are often referred to as lipids. Lipids that are solid at room temperature are called?
Fats
What are the key functions of lipids?
• Formation of cell membranes.
• Formation of myelin sheath within the nervous
system.
• Constitute a large majority of the central nervous system (CNS) and spinal cord.
• Synthesis of steroid hormones.
• Assist in the regulation of enzymes.
• Insulation through subcutaneous adipose tissue.
• Protection of internal organs.
• Transportation, storage and utilisation of fat-soluble
vitamins A, D, E and K.
• Fuel source during lower-intensity workloads.
• Storage of energy within the adipose tissue.
Fatty acids are the acids produced when?
When fats are broken down.
What is the natural basic structure of fatty acids?
Fatty acids naturally occur as triglycerides, where three fatty acids attach to a carbohydrate ‘backbone’ called
glycerol.
What are the purposes of fatty acids?
Fatty acids can help:
- Keep skin healthy
- Prevent early aging
- Promote weight loss by helping the body to process
cholesterol.
- The arteries to get rid of cholesterol build-up.
- Assist the adrenal and thyroid glands, which may also
help regulate weight.
The function and behavior of a fat is determined by?
By the structure of fatty acid chains, which can be different lengths and shapes.
In saturated fats, the chains are ‘filled’ with?
hydrogen
Why are saturated fats usually solid at room temperature?
Saturated fatty acids are straight and tend to arrange themselves more uniformly
Why should saturated fat be included within the daily diet?
• Enhancement of the immune system.
• Provision of energy and structural integrity to the
cells.
• Enhancement of liver function and offers some
protection from the toxic effects of alcohol and
some medications.
• The ability of coconut oil to act as an anti-microbial
and an antiviral agent.
In Unsaturated fat, why are the fatty acids are described as unsaturated?
Because hydrogen atoms are absent from portions of the carbon chains.
The function and behaviour of fat is determined by?
The structure and function of fatty acid chains.
In saturated fat, the chains are filled with hydrogen.
In unsaturated fat, hydrogen atoms are absent from portions of the carbon chains.
What is monounsaturated fat?
Oils that contain fatty acids with only one double bond. This means the molecule has a single bend in it.
What is polyunsaturated fat?
These fatty acids are long chains of carbon atoms; typically they are missing hydrogen at more than one point, so they have more than one double bond
(‘poly’ means many).
Diets high in monounsaturated fats have been
shown to lower levels of?
- LDL (low-density lipoproteins)
- Cholesterol (bad cholesterol)
- Plasma triglycerides (fat in the blood),
- The risk of coronary heart disease
For polyunsaturated fats, what are the two essential fatty acids (EFAs), and why are they essential?
Omega 3 and Omega 6 Fatty Acids are essential because the body can’t synthesize them itself.
Why are the omega 3 fatty acids found in oily fish particularly beneficial?
They have been shown to:
- reduce the blood’s tendency to clot
- Lower blood triglyceride levels
- Lower total cholesterol levels and, in some
individuals, to raise HDL (high-density lipoproteins) cholesterol
All of which are thought to lower the risk of CHD
Evidence indicates a significant link between disease and the consumption of heavily processed fats such as?
Vegetable oils
What is the process by which liquid oils are converted into solid, spreadable fats such as margarine?
Hydrogenation
How does hydrogenation of oils work?
Through a combination of heating and chemical manipulation, liquid unsaturated fats are converted to a solid, saturated form.
What are the potential by-products of the hydrogenation process, and why is this bad?
The by-product of hydrogenation is Trans fats.
This is bad because trans-fatty acids have adverse effects on blood lipid levels, promoting:
- An increase in LDL (or ‘bad’) cholesterol
- Decrease in healthier HDL cholesterol
- Effect is double that produced from the ingestion of
saturated fat.
Consumption of hydrogenated fats is associated with many other diseases, such as?
cancer, atherosclerosis, diabetes, obesity, immune system dysfunction, and problems with bones and tendons.
What percentage of the body’s cholesterol is the liver able to synthesise for itself?
75-80% of the body’s own supply.
What happens when dietary cholesterol intake is low, and what happens when dietary cholesterol intake is high?
When dietary cholesterol intake is low, the body increases the synthesis of its own supply, and when
dietary intake increases, cholesterol production falls.
What are lipoproteins, and why are they needed?
Lipoproteins are protein-based carriers that completely encase lipids for transportation in the blood.
These are needed because cholesterol is a lipid, which means it doesn’t mix with the watery medium of blood.
What are Very low-density lipoproteins (VLDL) and what is their function?
Very low-density lipoproteins (VLDL) are synthesised by the liver and contain cholesterol and triglycerides. They transport triglycerides into adipose tissue
What are Low-density lipoproteins (LDL) and what is their function and why are they ‘bad’?
Low-density lipoproteins (LDL) are formed from VLDLs once they have unloaded most of their triglycerides.
They transport the remaining cholesterol to cells throughout the body that are in need.
They are associated with increased availability of cholesterol to the tissues and therefore higher levels of blood cholesterol, which is why they are sometimes referred to as ‘bad cholesterol’.
What are High-density lipoproteins (HDL) and what is their function?
High-density lipoproteins (HDL) are synthesised by the liver and transport excess cholesterol from the tissues and blood back to the liver, potentially lowering blood cholesterol levels.
This is why they are sometimes referred to as ‘good cholesterol’.
What is the desirable upper limit of total cholesterol level
The desirable upper limit of total cholesterol level
has been identified as 5.2mmol/L.
What are vitamins?
Vitamins are a group of organic compounds (all containing carbon) that are required for normal growth and metabolism.
What are fat-soluble vitamins?
They can only be absorbed, transported and utilised in the presence of fat.
What are the four fat-soluble vitamins?
Vitamins A, D, E and K
What are the functions of Vitamin A?
- Stimulates gastric juices for protein digestion.
- Plays vital role in bone building.
- Maintains retinal health (vision).
- Protects against pollution and degenerative damage.
What are the Sources of Vitamin A?
- Butter from grass-fed cows.
- Pastured whole eggs.
- Liver.
- Seafood.
- Cod liver oil.
What are the functions of Vitamin D?
- Needed for calcium and phosphorus absorption.
- Helps form strong bones and teeth.
- Appears to protect against cancer and multiple
- sclerosis.
What are the Sources of Vitamin D?
- Butter from grass-fed cows.
- Pastured whole eggs.
- Liver.
- Seafood.
- Cod liver oil.
What are the functions of Vitamin E?
- Aids blood circulation.
- Helps with tissue repair and healing.
- Maintains structural integrity of cells (e.g. healthy
skin, nails and hair). - Slows ageing process.
- Acts as a powerful antioxidant.
- Together with certain trace minerals, protects against
cancer and CHD.
What are the Sources of Vitamin E?
Unrefined vegetable oils. Butter. Organ meats. Whole grains. Raw nuts and seeds. Dark green leafy vegetables.
What are the functions of Vitamin K?
Important role in blood clotting.
Aids bone formation.
What are the Sources of Vitamin K?
Liver. Pastured whole eggs. Butter from grass-fed cows. Whole grains. Dark green leafy vegetables.
What are the two water-soluble vitamins?
Vitamin B and Vitamin C
What are the functions/purposes of minerals?
- Minerals build strong bones and teeth, control body
fluids inside and outside cells, and turn the food we
eat into energy. - They allow our bodies to ‘unlock’ the energy
contained in our diet.
What are the 7 macrominerals
Calcium, Chloride, Magnesium, Phosphorus, Potassium, Sodium, and Sulfur.
What processes are minerals necessary for?
Minerals are necessary for structure and for the normal
regulation of metabolic, hormonal, and nervous interactions in the body.
What is the role of antioxidants?
Antioxidants play a vital role in offsetting some of the effects of aging and keeping the body youthful.
Antioxidants also protect against heart disease, cancer and other diseases.
What is the digestive tract?
The digestive tract is essentially a continuous,
hollow muscular tube (including the stomach) running from the mouth to the anus.
The organs of the GI tract include?
Mouth, pharynx, oesophagus, stomach, small intestine, large intestine and anus.
What are the two main functions of the digestive system?
Digestion and absorption of nutrients.
What and where is the Pharynx?
The PHARYNX is the part of the throat situated immediately below the nasal cavity, posterior to the
mouth and superior to the oesophagus and larynx.
What and where is the Oesphagus?
The OESOPHAGUS is the tube that carries food from the mouth to the stomach.
As it passes through the chest on its way to the stomach, it lies between the windpipe (trachea) and the spinal cord.
Where is the Pancreas?
The PANCREAS is quite high up in the abdomen. It lies across the body where the ribs meet at the bottom of the breastbone, just behind the stomach.
What and where is the Gallbladder?
The GALLBLADDER is a small, hollow, pear-shaped pouch about 8cm long and 2.5cm wide. It is
situated underneath the right side of the liver in the upper abdomen.
Where is the Gallbladder?
It can be found below the right lung, and it is protected by the lower ribs on that side. The liver is divided into two main lobes: the larger right
lobe and smaller left lobe.
What is Carbohydrate broken down into by the digestive system?
Glucose
What is Protein broken down into by the digestive system?
Amino Acids
What is Fat broken down into by the digestive system?
Free Fatty Acids
Where does most of the absorption of nutrients take place?
Most of the absorption of nutrients takes place in the small intestine.
Why are the internal walls of the small intestine arranged in a series of folds lined with microscopic hairs (microvilli)?
This provides a large surface area through which
nutrients can be absorbed into the bloodstream.
What intestine are Water and some vitamins absorbed in?
Large.
What are the food groups included in the 1992 Food Guide?
- Fats, oils, and sweets.
- Milk, yogurt, and cheese.
- Meat, poultry, fish, dry beans, eggs, and nuts.
- Fruit.
- Vegetables.
- Bread, cereal, rice, and pasta.
How often is the Food Guide reviewed in the USA?
Every 5 years.
In the EatwellGuide, what is the guidance on Fruit and Vegetables?
Eat at least 5 portions of a variety of fruit and vegetables every day.
In the EatwellGuide, what is the guidance on ‘Carbs’?
Base meals on potatoes, bread, rice, pasta, or other starchy carbohydrates; choosing wholegrain versions where possible.
In the EatwellGuide, what is the guidance on Dairy?
Have some dairy or dairy alternatives (such as soya drinks); choosing lower fat and lower sugar options.
In the EatwellGuide, what is the guidance on ‘Protein’?
Eat some beans, pulses, fish, eggs, poultry, and meat, and other proteins (including 2 portions of fish every week, one of which should be oily).
In the EatwellGuide, what is the guidance on ‘Oils and Spreads’?
Choose unsaturated oils and spreads and eat in small amounts.
In the EatwellGuide, what is the guidance on Fruit and Vegetables?
Drink 6-8 cups/glasses of fluid a day
The Eatwell Guide is also supported by eight specific healthy eating tips:
- Base your meals on starchy foods.
- Eat lots of fruit and vegetables (5 a day).
- Eat more fish (2 portions a week, 1 oily).
- Cut down on saturated fat and sugar.
- Try to eat less salt, no more than 6g a day.
- Get active and try to be a healthy weight.
- Don’t get thirsty, drink 6-8 cups of water a day.
- Don’t skip breakfast.
UK Dietary Reference Values (DRV): recommended
nutritional intakes for?
The population
Ingredients are listed on food labels in what order?
Descending weight order.
What is the Food Standards Agency (FSA) responsible for?
The Food Standards Agency is responsible for food safety and food hygiene across the UK.
Food production, labeling, and manufacture are governed by?
The Food Safety Act 1990.
What are the four major sweeteners used in foods?
- Aspartame.
- Sucralose.
- Acesulfame.
- Saccharin.
What are some of the key reasons for purchasing organic foods?
- Minimal use of additives.
- No pesticides, fungicides or herbicides used in
production. - No genetically modified foods used.
- No routine antibiotic use on animals.
