Topic 1 Flashcards
1
Q
How much total daily energy should come from carbohydrates according to the Acceptable macronutrient distribution range (AMDR)?
A
45-65% of total daily energy should come from carbs
2
Q
What elements do carbohydrates contain?
A
Contains the elements; carbon, hydrogen and oxygen
3
Q
How much energy (kj/g) does carbohydrates provide?
A
16.7kj/g
4
Q
Carbs are the only energy source used by both the…
A
Brain and nervous system. This makes them a very important energy source for the body
5
Q
The body requires carbs to:…
A
Provide heat and energy for daily activities.
Provide dietary fibre to stimulate the digestive system
6
Q
All CHOs are comprised of smaller monomers. Glucose is a CHO monomer… Within the cell, glucose is used to…
A
Create an energy-rich molecule called ATP via a process called respiration
7
Q
Carbs are classified depending on the number of subunits they contain. What are the four classifications?
A
Monosaccharides
Disaccharides
Oligosaccharides
Polysaccharides
8
Q
How many sugar molecules does a monosaccharide have?
A
One sugar molecules
9
Q
How many sugar molecules does a disaccharide have?
A
Two sugar molecules
10
Q
How many sugar molecules does an oligosaccharide have?
A
3-10 sugar molecules
11
Q
How many sugar molecules does a polysaccharide have?
A
10 or more sugar molecules
12
Q
Which carbs are simple?
A
Monosaccharides and disaccharides
13
Q
Which carbs are complex?
A
Oligosaccarides and polysaccarides
14
Q
List the monosaccharides
A
Glucose, fructose, galactose
15
Q
List the disaccharides
A
Sucrose, lactose, maltose
16
Q
List the oligosaccarides
A
Raffinose
17
Q
List the polysaccharides
A
Starch, glycogen, cellulose
18
Q
What are some properties me a monosaccharide?
A
Simple sugars, sweer to taste, soluble in water
19
Q
What is glucose?
A
A monosaccharide, (simple sugar), naturally occurs in honey, fruit + veggies. Most carbs are converted to glucose when digested
20
Q
What is fructose?
A
A monosaccharide (simple sugar), found naturally in honey, sweeter than table sugar (sucrose)
21
Q
What is galactose?
A
A monosaccharide (simple sugar) formed from digestion of lactose (disaccharide) from milk
22
Q
What are some properties of a disaccharide?
A
Simple sugar, sugars made up of 2 monosaccharide units, sweet to taste but varies, soluble in water
23
Q
What monosaccharide units makeup sucrose? Where can it be found?
A
Glucose + fructose
Table sugar obtained from sugar cane
obtained from sugar beet
24
Q
What monosaccharide units makeup lactose? Where can it be found?
A
Glucose + Galactose
Obtained from dairy products
All milk produced by humans and animals contain lactose
25
What monosaccharide units makeup Maltose? When is it produced?
Glucose + Glucose
Produced when starchy foods are digested
26
List some properties of oligosaccharides
has 3-10 monomers
Slightly sweet
Human body is unable to digest these, but bacteria in our large intestine can.
27
List some properties of polysaccharides
Complex group of carbs with many glucose units joined together.
The number and arrangement of the glucose molecules affects properties including taste and if the body can digest the polysaccharide.
Not soluble in water but can absorb water.
Not sweet to taste
28
Where is fibre found and what is it required for?
Found in plant foods (cereals, fruits and vegetables) fibre is the undigested part of the food. Required for good bowel health
29
What do soluble fibre, resistant starch and oligosaccharides do? *check this with Miss to double check that is correct*
Bind with water and partly dissolve forming a thick gel in the stomach.
30
What does the gel in the stomach do?
Expands the stomach providing satiety (fullness).
Slows the release of food from stomach into small intestine, slows digestion allowing for gradual absorption of nutrients.
Stabilises blood glucose levels = sustained energy.
Can lower cholesterol levels by trapping bile (made from cholesterol) preventing reabsorption.
Moves into large intestine as gel forming soft stools.
Partly digested by bacteria in large intestine
31
What does insoluble fibre do?
Absorbs water adding bulk to stools.
Bulky stools move through the LI easily, reducing transit time
32
What are some examples of insoluble fibre?
Skin of fruit, veggies and nuts
33
What is diverticulosis
Due to constipation, the dry, hard faeces place pressure on the wall of the large intestine causing it to rupture and form pouches.
Usually no symptoms
34
What is diverticulitis, and what are some symptoms?
When the pouches become inflamed or infected due to trapped food or faeces.
Symptoms: Cramping pain, bloating, fever, blood in faeces.
35
How can you prevent diverticulitis?
Exercise can help to prevent by promoting strong intestinal muscles, allowing for more efficient contractions to expel faeces
36
What can overconsumption of CHO lead to?
Excess carbs, especially simple CHO can lead to:
-obesity
-Cardiovascular disease
-type 2 diabetes
37
What is type 2 diabetes?
A progressive condition where the body becomes resistant to normal effects of insulin, requiring more and more insulin to be produced. Overtime the pancreatic cells lose the ability to produce enough insulin therefore blood glucose levels rise.
38
What are some causes of type 2 diabetes?
Genetic link, weight gain, high sugar intake
39
What is some ways in which you can manage type 2 diabetes?
Regular exercise (to burn excess glucose)
Healthy eating (Low CHO, especially simple CHO)
Weight reduction
40
What are some symptoms of type 2 diabetes?
Excessive thirst
passing more urine
feeling tired and lethargic
always feeling hungry
having cuts that heal slowly
gradually putting on weight
41
Food is required for...
Body growth and repair
energy
warmth
protection from disease
regulation of body processes
42
The nutrients found within food are...
Macronutrients: Carbohydrates, lipids and proteins
Micronutrients: Vitamins and minerals
Water
43
Macronutrients provide the body with...
energy
44
How much energy do carbohydrates provide the body?
16.7kj/g
45
How much energy do proteins provide the body per gram?
16.7kj/g
46
How much energy do lipids provide the body per gram?
37.7kj.g
47
How much energy does alcohol provide per gram? (remember that alcohol is not considered a macronutrient)
29.3kj.g
48
How do you calculate the amount of energy in food labels?
You times the amount of carbs (or protein or fats etc) by the amount of energy that macronutrient provides per gram.
E.g a food that contains 76.2g of carbohydrates = 76.2 x 16.7 = 1272.54kj
49
What is the energy distribution formula?
Macronutrient energy/total energy x 100
e.g total energy of the food = 1446.14kj
carbs in a food = 1272.54kj
therefore, (1272.54/1446.14) x 100 = 87.9%
50
What is the acceptable macronutrient distribution range? (AMDR)
Is the recommended balance of macronutrients for individuals of a healthy weight to reduce the risk of developing diet-related disorders
(Not recommended for individuals who whish to lose weight or have a specific health issue)
51
What is the AMDR for carbs, fat and protein?
carbs = 45-65%
Fat = 20-35%
Proetin = 15-25%
52
How many grams of alcohol is in a standard drink?
10 grams
53
the formula to work out the amount of energy provided by alcohol is...
(10g x standard drink) x 28.3kj
e.g
Can of beer = (10x0.8) x 29.3 = 235/4kj
Red wine = (10x1.6)x29.3 = 468.8kj
54
What are the nutrient reference values? (NRV)
a set of nutritional intake recommendations (Based on individual need)
55
What is the estimated average requirement (EAR)
The average amount of nutrients estimated to meet the nutrient requirements of half of a group of healthy individuals
56
What is the recommended daily intake (RDI)
The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all healthy individuals
57
What is adequate intake (AI)
The average amount of nutrients that a group of healthy individuals requires. Used when EAR can not be determined
58
what is the tolerable upper intake level?
The upper level is the amount, if exceeded can be toxic
59
What is the Estimated energy requirement (EER)?
The average dietary intake (kj/day) required to maintain energy balance. Used by individuals of a healthy weight and activity level
60
What are proteins?
Are are large molecules made up of a unique sequence of amino acids, amino acids are comprised of carbon, hydrogen, oxygen and nitrogen (amino means contains nitrogen)
61
Proteins are the only nutrient that...
supplies the body with nitrogen - needed to make other proteins in the body
62
How much energy do proteins produce?
16.7kj/g
63
Explain the structure of an amino acid
All have the same structural formula - a central carbon atom bonded to one hydrogen atom, an amino group and a carboxylic acid group.
(Side chain is different and unique and effects shape size and electrical charge)
64
What is an essential amino acid?
needs to be consumed via diet as the body cannot synthesis or does not produce enough to meet nutrient needs
65
What is a non-essential amino acid?
can be synthesised by the body so is not essential to be consumed via diet
66
Explain conditionally essential amino acids
Non-essential amino acids can at times require higher levels than the body can make e.g during illness or growth. These times they are called conditionally essential amino acids
67
What are complete proteins?
Protein sources that contain all essential amino acids in the amount required
68
what is an example of a complete protein?
Animal food sources are complete proteins and have high biological value
69
What are incomplete proteins?
proteins sources that are missing or are low in one or more of the essential amino acids
70
What is a complementary protein?
when incomplete proteins are consumed together (either in the same meal or over the day) and provide all essential AA.
e.g eating beans and rice together
71
The body requires protein for...
Maintenance and repair of every cell in the body.
(there are about 42 million proteins in every cell)
72
What do enzymes do?
speed up chemical reactions
73
What do antibodies do?
fight foreign microbes
74
What is the protein RDI?
15-25% of total daily kj consumption should be protein
(Males required greater amount as they generally have greater muscle mass than females
75
Explain what happens when there is an overconsumption of protein
Body cannot store amino acids which will be excreted however other compounds can be converted to glucose/glycogen/lipids for use and storage.
Waste products from protein metabolism is processed and removed by the liver and the kidneys so extra strain can be put on these organs if protein consumption is excessive.
- Many sources also high in saturated fats so obesity which can lead to heart disease
- Increased blood cholesterol can also be result of over eating protein
76
Micronutrients are required by the body for...
good health and for the prevention of any diet-related disorders
77
Are micronutrients required in small or large amounts in the body?
required in small amounts
78
Most micronutrients are considered essential meaning they...
Must be consumed in the diet as the body cannot synthesise them
79
Compare the chemical composition of vitamins and minerals
Vitamins: Organic substance - complex structure containing carbon, oxygen + hydrogen
Minerals: Inorganic substances - Simple structures and ions
80
Compare the sources of vitamins and minerals
Vitamins: Found in plants + animals
Minerals: Found in soil + rocks, easily absorbed by plants
81
Compare the vulnerability of vitamins and minerals
Vitamins: Denature by heat in cooking, age, sunlight and other chemical reactions
Minerals: Maintain their structure and are not affected by heat, sunlight and other chemical reactions
82
List the water-soluble vitamins
B group vitamins, C
83
List the fat-soluble vitamins
A, D, E, K
84
Vitamin classification:
Compare the transportation in the body for water/fat-soluble vitamins
Water-soluble: Dissolve in water. they are freely and easily transported throughout the body by the blood (watery substance)
Fat-soluble: Dissolve in fats/oils. they require transport by carriers (protein or lipoproteins) i the blood stream
85
Vitamin classification:
Compare the absorption of water/fat-soluble vitamins
Water-soluble: Move directly into the blood due to being able to dissolve in water
Fat-soluble: Enter via the lymphatic system with fats, before making their way into the blood stream
86
Vitamin classification:
Compare the storage in body for water/fat-soluble vitamins
Water-soluble: The body cannot store them. Any excess of water-soluble vitamins pass out of the body primarily through urine
Fat-soluble: Are stored in adipose tissue and the liver
87
B group vitamins act as...
Coenzymes (allows enzymes to function) in the metabolism of macronutrients, aiding the release of their energy
88
B group vitamins include...
B1 (thiamine), B2 (riboflavin) and B3 (niacin)
89
Low vitamin B levels can lead to...
low energy levels
90
Explain the functions of folate (B9)
- Like most other water-soluble B vitamins, folate assists the metabolism of macro-nutrients to produce energy.
- Works as a coenzyme in the metabolism of amino acids in proteins
- Also acts as a coenzyme in the synthesis of DNA in rapidly dividing cells
- Is require in the formation of red blood cells
91
What happens if there is a deficiency of folate (B9)
The folate required for good health increases significantly during pregnancy, increasing the risk of deficiency.
- Inadequate folate a month prior to conception and during pregnancy, especially in the first trimester is linked to the development of neural tube defects where the tube does not fuse properly
- Most common types are anencephaly and spinal bifida
92
What is anencephaly?
The neural tube fails to close resulting i the brain missing or failing to develop. This often results in miscarriage or the infant dying shortly after birth
93
What is spina bifida?
more common and is classified as the incomplete closure of the spinal cord where the signal chord produces a sac. Spina bifida can also be accompanied by degrees of paralysis, kidney disorders, curvature of the spine, muscle weakness, motor and sensory losses
94
What is anaemia?
General term used for low red blood cells or haemoglobin in the RBC
95
What is megaloblastic anaemia?
Low folate levels disrupt the DNA synthesis in the formation of RBC. Without folate, DNA damages and destroys many of the RBS as they attempt to divide and mature
- This results in larger immature RBC and the RBC are unable to carry oxygen efficiently or travel through the capillaries as efficiently
- therefore the amount of oxygen delivered to the body and the rate that it is delivered is decreased. Fatigue is the main symptom of this condition
96
What is the chemical name for vitamin B9?
Folate and folic acid
97
Describe the form of folate (B9)
Folate is the form that naturally occur nd is found in foods, most commonly in foliage of leafy greens
98
Describe the form of folic acid (B9)
Flic acid is the synthetic form which is commonly added to foods
* - potential risk of underconsumption saw the mandatory fortification of breadmaking flour with folic acid in aus and nz in 2009
99
What is the chemical name of B12 when it is found naturally in food?
Cobalamin
100
Where is B12 found?
B12 is only found in trace amounts in plant sources --> animal sources are key
101
Where is B12 stored?
One of the few water-soluble vitamins that can be stored in the body. It is store in the liver and muscles of animals, therefore making liver, fish, poultry and other meats good sources
102
What are some good sources of B12 for vegans?
B12 supplements and fortified products such as soymilk and cereals
103
Explain the deficiency of B12
- Like folate, it works as a coenzyme in DNA synthesis in RBC formation and in the metabolism of macronutrients, specifically amino acids.
- B12 is also required to change folate into its active form
- Low B12 results in pernicious anaemia (a type of megaloblastic anaemia) causing low numbers of RBC to be created
104
What is vitamin c (ascorbic acid?)
Is a water-soluble vitamin and found in most fruits and vegetables
105
What are some good sources of vitamin C?
Guava, capsicum, kiwi and strawberries contain a significant amount of vitamin c
green leafy vegetables such as Brussel sprouts, spinach and broccoli are also good sources
106
What are the functions of vitamin C?
Important in the synthesis of collagen, the most abundant protein in the body.
107
Collagen is the main component in...
connective tissues, and serves as a matrix on which bone and teeth form
108
What does collagen assist in?
Assists in gluing separated tissues together, forming scars and helping to hear wounds
109
Vitamin c also acts as an antioxidant what does this mean?
antioxidant means it defends the body against free radicals
110
What are free radicals?
Free radicals cause oxidative stress to cells and tissues, accelerating the ageing process.
Free radicals also damage DNA, proteins and cell membranes, preventing cells from functioning normally and potentially causing the development of some cancer
111
When consumed in the same meal, vitamin c will improve the absorption of...
iron digested from food into the bloodstream
112
What disease can occur if there is a deficiency in vitamin c?
Scurvy
113
What is scurvy?
Scurvy is a deficiency disease associate with a lack of vitamin c
114
What are the symptoms of scurvy?
Initial symptoms include fatigue, inflammation of gums and generally feeling unwell
As it progresses, so do the symptoms including small red/purple spots and bruises on skin from broken bleeding capillaries, joint pain, swollen and bleeding gums and loosening teeth
- directly correlated to an impairment of collagen synthesis as this process is driven by vitamin c
115
With a lack of vitamin c why would wounds not heal as effectively?
When collagen synthesis fails, connective tissues become weak and wounds do not heal as effectively
116
Why is vitamin D (calciferol) different to other vitamins?
because the human body can synthesise it with the help of sunlight and form a precursor that the body makes from cholesterol
117
Explain the series of reactions that turn cholesterol precursor into vitamin D in its active form.
1. UV light: natural sunlight hits the skin which absorbs the UV rays
2. Enzymes: This uv radiation reacts with enzymes in the skin, initiating the production of vitamin D
3. Vitamin D: The precursors created by this reaction are converted to vitamin D
4. In the body: Vitamin D acts on a number of cells and tissues throughout the body, stimulating growth and nutrient reabsorption
118
Very few food sources contain vitamin D, what are some good sources?
oily fish (salmon, herring), liver, eggs and fortified margarine
119
What are the functions of vitamin D?
Important for increasing the blood concentration of calcium and phosphorus.
120
How does vitamin D increase the blood concentration of calcium and phosphorus.
It does this by enhancing their reabsorption from the small intestine into the blood
- reducing the amount lost via the urine by enhancing their reabsorption by the kidneys
- Enhancing the mineral movement into the bones
- This allows bones to grow denser and stronger as they absorb and deposit these minerals
121
What happens if there is a deficiency of vitamin D?
Chronic hypovitaminosis impairs calcium and phosphorus absorption. This leads to failure of the bones to calcify normally, causing the softening of the bones, growth retardation and skeletal abnormalities.
122
Prevalence of hypovitaminosis in children leads to rickets. What is rickets?
Where bones become weak so that they bend when they try to support the child's weight, causing bowed legs.
123
What is vitamin k?
Is a coenzyme for the enzyme required for the synthesis of proteins involved in blood clotting. It is also a cofactor for a protein require for building bone density.
124
Where is vitamin K found?
Is a fat solubke vitamin that is naturally resent in some foods including leafy greens (spinach, brussel sprouts, broccoli, lettuce)
It is also produced by bacteria in the large intestine of humans
125
What happens when there is a deficiency of vitamin k?
A vitamin k deficiency can occur during the first few weeks of infancy due to low transfer during pregnancy and/or low vitamin k content in breast milk. In Australia, new borns are given a vitamin k injection at birth.
126
What are lipids comprised of?
Carbon, hydrogen and oxygen
127
How many main types of lipids are there?
There are 3 main types of Lipids
128
Triglycerides...
make up 95% of the lipids we eat and 99% of the lipids we store in our body as adipose tissue
The remaining 5% is phospholipids (used in cell structure) and sterols (such as cholesterol)
129
What is a triglyceride composed of?
A triglyceride is composed of one molecule of glycerol and 3 fatty acid chains
130
What are fatty acid chains?
Phospholipids and triglycerides contain fatty acid chains
- Carbon chains containing between 2 and 24 carbons with a methyl group at one end and an acid group at the other end
131
What do saturated fatty acids contain?
Contain single bonds, allowing each carbon atom to hold the maximum amount of hydrogen
132
What are some properties of a saturated fatty acid?
Solid at room temperature and have a high melting point.
133
Where can saturated fatty acids be found?
Found in animal fats such as meat and milk and in some plants such as palm and coconut oil
134
What is an unsaturated fatty acid?
Contains double bonds, therefore the fatty acid does not hold the maximum amount of hydrogen
135
What are some properties of unsaturated fatty acids/where are they found?
Generally liquid at room temperature and have a low boiling point.
Found in nuts seeds and oils such as vegetable oils
136
How many bonds does a monosaturated fat have?
single double bonds
137
How many bonds does a polyunsaturated fat have?
2 or more double bonds
138
How are polyunsaturated fats identified?
By te location of the first double bond in relation to the methyl group
139
Omega-3 and omega-6 are considered...
essential fatty acids. These triglycerides cannot be synthesised in the body and must therefore be consumed in the diet.
140
What is omega-3 fatty acids (linolenic acid) required for?
- Slows the build-up of fatty material on walls of arteries
- Reduces chance of blood clot
- lowers triglyceride levels
- Reduces high blood pressure
- Foetal brain growth + function
141
What is omega-6 fatty acids (linolenic acid) required for?
Required for regulation of:
- blood pressure
- Blood clot formation
- Immune response
- Nerve impulse
142
List some sources of omega-3 fatty acids (linolenic acid)
Fish oils, walnuts, flaxseeds, soy
143
List some sources of omega-6 fatty acids (linolenic acid)
Sunflower oil, safflower oil, corn oil
144
Are trans-fatty acids found in food?
Some foods naturally contain trans fatty acids, but their levels are low
145
There are two types of double bonds that exist naturally.. what are these?
Cis (hydrogen on the same side)
Trans (Hydrogen on opposite side)
146
What do cis bonds do?
Cis bonds cause the fatty acid to kink, resulting in them to be liquid at room temperature (oils). They are more likely to react with oxygen and go rancid.
147
What is hydrogenation?
Hydrogenation is a process used by food manufactures which converts cis to a trans double bond. This is done by forcing hydrogen gas into oils under pressure. This changes the oil to be semi-solid and less likely to go rancid.
- found in commercially made foods such as pastry, cakes nad biscuits and partially hydrogenated oils use of deep frying
148
What is sterols (cholesterol) composed of
is composed of a glycerol molecule and fatty acid chain like triglyceride, however, they are fused, forming rings.
149
Describe some properties of cholesterol and hence how it is transported.
Cholesterol is a waxy substance and is only slightly soluble in water and blood. It therefore requires transport via hydrophilic proteins and lipoproteins
150
How many lipoproteins does the body make
4 different lipoproteins, differentiated by their size and density. The greater the proportion of proteins the greater the density whereas a greater proportion of lipids decreases the density.
151
LDL's (low-density lipoproteins) are linked to...
increased plaque build-up on artery walls
152
HDL's (High-density lipoproteins) are linked to...
removal of plaque on artery walls
153
How much energy do lipids provide per gram?
37.7kj
154
What is the AMDR for total fats?
The AMDR for total fats is 20-35%
155
What are some functions of lipids
- Helps to retain heat by acting as an insulating layer just below your skin
- Surround and protect vital internal organs
-Acts as the carrier for fat-soluble vitamins (A,D,E,K) and cholesterol
-Prevents skin from becoming dry
-Used to produce cell membranes
- Used to produce hormones
-Contribute to feeling of satiety
-Affect the palatability of foods, enhancing flavour and texture
-Provide essential fatty acids which the body can not synthesis.
156
What happens when there is excess fat?
Excess fat is stored in adipocyte cells as adipose tissues and can lead to obesity. Stored until needed as energy
157
What can excess fat lead to?
This contributes to a range of lifestyle diseases including
- Hypertension (high blood pressure)
- Atherosclerosis (hardened arteries due to plaque)
- Heart disease (heart attack)
- Stroke (death of brain tissue due to lot)
- Type 2 diabetes (obesity is key trigger)
158
What is atherosclerosis?
Is the term used for the hardening of the arteries and is a precursor for hypertension and cardiovascular disease
As plaque is deposited on artery walls, especially at branch points, it narrows the lumen and causes a hardening of the endothelial wall
159
List and explain the stages of atherosclerosis
1. it is believed that endothelial damage, due to dietary or lifestyle risk factors (LDL's, sugars, smoking) causes atherosclerosis.
2. LDL cholesterol becomes trapped at the damage site, causing WBC to arrive and engulf the LDLs. The WBCs now called foam cells are now also trapped. These cells congregate forming a 'fatty streak'. over years this continued build-up is called plaque
3. A fibrous capsule is formed to protect the artery, allowing for continued blood flow
4. The plaque will be stabilised if no more build-up occurs. If further thickening occurs, the wall becomes so stretched it begins to stiffen. Calcium may also be deposited and further harden the arteries
160
When does cardiovascular disease occur?
Occurs when plaque from the later stages of atherosclerosis ruptures forming a blood clot blocking blood flow
161
Atherosclerosis can also cause...
an aneurysm due to a bulge in the blood vessel. If the vessel bursts it will lead to internal bleeding. Clots prevent blood and therefore oxygen and nutrients from moving to cells. This can therefore cause death of that region of the body
162
