Fat Soluble Vitamins Flashcards
(474 cards)
1
Q
What is a common myth about vitamins?
A
If a little is good, then a lot is better
This myth suggests that higher doses of vitamins are always beneficial, which is not true.
2
Q
What are the natural sources of vitamins?
A
All food groups
Vitamins can be found in a variety of foods, including fruits, vegetables, grains, protein sources, and dairy.
3
Q
What are enriched and fortified foods?
A
Foods that have had vitamins added to them
Enrichment refers to adding nutrients back that were lost during processing, while fortification involves adding nutrients that are not naturally present.
4
Q
How do vitamins compare to macronutrients?
A
Vitamins don’t provide energy and are needed in smaller amounts
Unlike macronutrients (carbohydrates, proteins, and fats), vitamins do not supply calories.
5
Q
What is the structure of vitamins?
A
Organic
Vitamins are organic compounds, meaning they contain carbon and are essential for various bodily functions.
6
Q
What does ‘vita’ mean?
A
Life
‘Vita’ is a Latin term that signifies life.
7
Q
What does ‘amine’ refer to in the context of vitamins?
A
Containing nitrogen
The first vitamins discovered were noted for containing nitrogen.
8
Q
When were vitamins first recognized?
A
In the early 1900s.
9
Q
What role do vitamins play in living cells?
A
They act as ‘co-factors’ catalysing chemical reactions in metabolic pathways.
10
Q
Name one function of vitamins.
A
Antioxidants.
11
Q
What are coenzymes?
A
Enzyme activators.
12
Q
What are vitamins constituents of?
A
Structural or process molecules.
13
Q
What are vitamins precursors of?
A
Structural or process molecules.
14
Q
What type of activities do vitamins participate in?
A
Electro-chemical activities.
15
Q
Can most vitamins be synthesized by the body?
A
No.
16
Q
How must vitamins be obtained if they cannot be synthesized by the body?
A
Through food and diet.
17
Q
Fill in the blank: Some dietary intake of vitamins remains _______.
A
essential.
18
Q
What are vitamins found in foods?
A
Vitamins are found in foods in small amounts and are only required in very small quantities, e.g. a few micrograms (ug) or milligrams (mg)
Vitamins are essential for various metabolic processes in the body.
19
Q
What happens if a particular vitamin is lacking in the diet?
A
The metabolic reactions which depend on it will fail
This can lead to various health issues and deficiencies.
20
Q
What can be the consequences of vitamin deficiency?
A
Deficiency of a vitamin can be irreversible or fatal
Some vitamin deficiencies can lead to serious health problems.
21
Q
True or False: Excessive amounts of vitamins can be harmful.
A
True
Excessive intake of certain vitamins can lead to toxicity and severe health issues.
22
Q
Can vitamins be destroyed?
A
Yes, vitamins can be destroyed (unlike minerals)
This can occur through cooking, storage, or exposure to light.
23
Q
What are vitamins?
A
Vitamins are organic compounds that are essential for various bodily functions.
24
Q
How were vitamins initially classified?
A
Vitamins were initially classified by letter because their chemical structure was unknown.
25
What are the two main classifications of vitamins based on solubility?
Fat-soluble and water-soluble vitamins.
26
Why is the classification of vitamins based on solubility useful?
It provides indications of likely food sources, function, distribution in the body, and potential toxicity.
27
Fill in the blank: Vitamins are classified into fat-soluble and _______ vitamins.
water-soluble
28
True or False: The classification of vitamins by letter is based on their known chemical structure.
False
29
What does the classification of vitamins help to indicate?
It helps to indicate likely food sources, function, distribution in the body, and potential toxicity.
30
What is the vitamin B group?
A group of water-soluble vitamins essential for various metabolic processes
## Footnote
Includes several vitamins like B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin)
31
What type of vitamins are classified as water-soluble?
Vitamins that dissolve in water and are not stored in the body
## Footnote
Includes vitamin C and the B vitamins
32
What is vitamin C known for?
An essential nutrient that acts as an antioxidant and supports the immune system
## Footnote
Also known as ascorbic acid
33
What are fat-soluble vitamins?
Vitamins that are soluble in fats and oils and can be stored in the body's fatty tissues
## Footnote
Includes vitamins A, D, E, and K
34
What is vitamin A important for?
Maintaining healthy vision, skin, and immune function
## Footnote
Can be found in foods like liver, fish, and dairy products
35
What is the role of vitamin D?
Supports calcium absorption and bone health
## Footnote
Can be synthesized by the body through sunlight exposure
36
What function does vitamin E serve?
Acts as an antioxidant, protecting cells from damage
## Footnote
Found in nuts, seeds, and green leafy vegetables
37
What is the significance of vitamin K?
Essential for blood clotting and bone metabolism
## Footnote
Can be found in green leafy vegetables and fermented foods
38
What are the water-soluble vitamins mentioned?
Vitamin B (including biotin, folate, and B12), Vitamin C (ascorbic acid)
## Footnote
Water-soluble vitamins are not stored in large amounts in the body and need to be ingested daily.
39
Which water-soluble vitamin is destroyed by heat?
Vitamin C, B6, folate
## Footnote
These vitamins are particularly vulnerable to cooking losses.
40
What happens to water-soluble vitamins when exposed to sunlight?
Vitamin B is destroyed by sunlight
## Footnote
This highlights the importance of proper storage and handling of these vitamins.
41
How are water-soluble vitamins stored in the body?
Stored in very small amounts and excreted in urine
## Footnote
This necessitates daily ingestion to maintain adequate levels.
42
Is toxicity common with water-soluble vitamins?
Toxicity is rare
## Footnote
This is due to their excretion through urine and low storage in the body.
43
Fill in the blank: Water-soluble vitamins need to be ingested _______.
daily
## Footnote
This is essential for maintaining health and preventing deficiencies.
44
What are the four fat-soluble vitamins?
A, D, E, and K
## Footnote
These vitamins are essential for various bodily functions and are stored in the body's fatty tissues.
45
Where are fat-soluble vitamins commonly found?
In the oily parts of foods
## Footnote
Foods like oils, nuts, and fatty fish are rich sources of these vitamins.
46
How are fat-soluble vitamins affected by cooking?
Less easily destroyed and lost from food by heat
## Footnote
Unlike water-soluble vitamins, fat-soluble vitamins are more stable during cooking.
47
Do fat-soluble vitamins dissolve in cooking water?
No
## Footnote
They do not dissolve in water, which helps preserve their content during cooking.
48
What is required for the absorption and transport of fat-soluble vitamins from the GI tract?
Bile secretion and normal fat absorption mechanisms
## Footnote
Bile emulsifies fats, aiding in the absorption of these vitamins.
49
What can impair the absorption of fat-soluble vitamins?
Impaired absorption mechanisms or a low-fat diet
## Footnote
Conditions affecting bile production or a diet low in fats may lead to deficiencies.
50
What are fat-soluble vitamins absorbed with?
Digested fat into chylomicrons
## Footnote
They are transported in the lymph system.
51
Where do fat-soluble vitamins ultimately reach for processing?
The liver
## Footnote
This is where they undergo various metabolic processes.
52
Why are fat-soluble vitamins not excreted in urine?
Due to their insolubility in water
## Footnote
They are stored in the body instead.
53
Where are fat-soluble vitamins primarily stored in the body?
In adipose tissue and the lipid component of liver cells
## Footnote
This allows for long-term storage.
54
How often is it essential to consume fat-soluble vitamins?
Not on a daily basis
## Footnote
Stores can last for up to a year.
55
How long can the stores of fat-soluble vitamins last?
Up to a year
## Footnote
This highlights their long-lasting nature.
56
Which fat-soluble vitamins can be toxic in large amounts?
Vitamins A and D
## Footnote
High intake levels should be avoided.
57
True or False: Fat-soluble vitamins are easily excreted in urine.
False
## Footnote
They are stored in the body rather than excreted.
58
Fill in the blank: Fat-soluble vitamins are transported in the _______.
Lymph system
## Footnote
They enter the bloodstream after reaching the liver.
59
What happens to beta-carotene once it is absorbed?
It can be cleaved in the middle to yield two molecules of vitamin A.
60
What are provitamins?
Inactive form of vitamin - gets activated in the body.
61
When calculating vitamin intake or requirements, what must be considered?
Need to account for provitamins.
62
Fill in the blank: Beta-carotene is a _______.
vitamin A precursor.
63
What factors influence vitamin content in food?
Vitamin content varies due to:
* Plant sources - sunlight
* Soil
* Growing conditions
* Plant's maturity at harvest
* Animal sources less variable
* Packaging and storage
* Food processing and cooking
## Footnote
These factors can significantly impact the nutritional value of food.
64
True or False: Vitamin content in animal sources is highly variable.
False
## Footnote
Animal sources of vitamins tend to have less variability compared to plant sources.
65
Fill in the blank: The vitamin content in food can be affected by _______.
[factors like plant sources, animal sources, packaging, storage, food processing, and cooking]
66
What are the main sources that affect vitamin content?
Main sources include:
* Plant sources
* Animal sources
* Packaging and storage
* Food processing and cooking
## Footnote
Each source contributes differently to the overall vitamin levels in food.
67
List two factors that affect vitamin content in plant sources.
* Sunlight
* Soil
## Footnote
These environmental factors play a crucial role in the vitamin levels of plants.
68
What is a key consideration when storing food that affects its vitamin content?
Packaging and storage
## Footnote
Proper storage can help maintain the vitamin levels in food.
69
What is the key active form of vitamin A?
Retinol
## Footnote
Retinol is considered a key player among the retinoids.
70
List the active forms of vitamin A.
* Retinol
* Retinal
* Retinoic acid
## Footnote
These forms are collectively known as retinoids.
71
What are provitamin A compounds?
Some carotenoids, e.g. beta-carotene
## Footnote
Provitamin A compounds are precursors that the body can convert into active vitamin A.
72
True or False: Retinal is an inactive form of vitamin A.
False
## Footnote
Retinal is one of the active forms of vitamin A.
73
Fill in the blank: The three active forms of vitamin A are ______, retinal, and retinoic acid.
retinol
74
What is the role of beta-carotene in vitamin A?
It is a provitamin A compound
## Footnote
Beta-carotene can be converted into active vitamin A in the body.
75
What is the active form of vitamin A?
Retinol
## Footnote
Retinol is crucial for various bodily functions, including vision and immune function.
76
What is beta-carotene?
A provitamin converted to retinol in the small intestine
## Footnote
Beta-carotene is a precursor to vitamin A.
77
List the three active forms of vitamin A.
* Retinol
* Retinal
* Retinoic acid
## Footnote
These forms play significant roles in bodily processes.
78
What are some functions of vitamin A?
* Vision
* Sexual reproduction
* Bone health
* Immune function
* Cell differentiation
## Footnote
Vitamin A is essential for maintaining several critical physiological functions.
79
True or False: Retinol and retinal can be converted interchangeably.
True
## Footnote
This interchangeability is important for the body's use of vitamin A.
80
What happens to retinal in the formation of retinoic acid?
It is converted to retinoic acid in an irreversible process
## Footnote
This conversion emphasizes the importance of retinal in vitamin A metabolism.
81
Fill in the blank: The three active forms of vitamin A are retinol, retinal, and _______.
retinoic acid
## Footnote
Retinoic acid plays a vital role in gene expression and cellular differentiation.
82
What is necessary to demonstrate that a compound is a vitamin?
A deficiency will lead to a specific clinical deficiency disease and abnormal metabolic signs, and restoration of the compound will prevent or cure the disease and normalize metabolic abnormalities.
83
What are the two factors found in milk that are essential for growth?
Factor A (found in cream) and Factor B (found in the watery part of milk).
84
What was Factor B chemically identified as?
'Amine', hence the term 'vital amine' first coined in 1913.
85
What is Niacin commonly known as?
Vitamin B3.
86
Which vitamins contain amines?
* Vitamin B6
* Folate
* Vitamin B12
87
Do vitamins provide energy?
No, but they play crucial roles in facilitating chemical reactions for energy extraction from macronutrients.
88
Which vitamins can humans not synthesize?
* Vitamin A
* B1 (thiamine)
* B2 (riboflavin)
* B5 (pantothenic acid)
* B6 (pyridoxine)
* B7 (biotin)
* B9 (folate)
* B12 (cobalamin)
* E
* K
89
Which vitamins can humans synthesize?
* Some vitamin B3 (niacin)
* Vitamin D
90
Fill in the blank: If vitamins cannot be produced in amounts needed by the body, some dietary intake remains _______.
essential
91
True or False: All vitamins provide energy.
False
92
What are minerals unable to be destroyed by?
Heat, air, acid, or mixing
93
What is required to demonstrate that a compound is a vitamin?
A deficiency will lead to a specific clinical deficiency disease and abnormal metabolic signs, and restoration will prevent or cure the deficiency disease
94
What were the two factors identified in milk for animal growth?
Factor A (in cream) and Factor B (in watery part of milk)
95
What is Factor B chemically identified as?
An 'amine'
96
What term was first coined in 1913 to describe vital amines?
Vital amine
97
True or False: Minerals can be destroyed by heat.
False
98
Fill in the blank: To demonstrate a compound is a vitamin, restoration of the compound will _______ or cure the deficiency disease.
Prevent
99
What type of diet was used in studies on milk to determine essential components for growth?
A diet of purified fat, carbohydrates, protein, and mineral salts
100
How are fat-soluble vitamins absorbed?
Similar to dietary fats, with incorporation into micelles
## Footnote
This process involves packaging into chylomicrons within intestinal cells.
101
What happens to chylomicrons after they are formed?
They move to lymphatic circulation before being transported to the blood
## Footnote
This transport is crucial for delivering fat-soluble vitamins.
102
What do cells do with triglycerides (TGs) from chylomicrons?
Cells take up most of the TGs and leave behind chylomicron remnants
## Footnote
Chylomicron remnants contain fat-soluble vitamins.
103
What does the liver do with chylomicron remnants?
Picks them up and either stores the vitamins or repackages them for delivery to other tissues
## Footnote
This storage and repackaging is essential for maintaining vitamin levels in the body.
104
How are water-soluble vitamins absorbed?
Similar to glucose and amino acids, directly into the blood
## Footnote
This absorption method allows for efficient uptake of these vitamins.
105
What is the absorption efficiency range for dietary fat?
40-90% of that consumed
## Footnote
Efficiency decreases as dietary intake rises above the body's needs.
106
What is the primary function of retinol-binding protein (RBP)?
Carries retinol released by the liver
## Footnote
RBP is crucial for the transport of vitamin A in the bloodstream.
107
Where does the liver store vitamin A?
Reserves are stored in the liver, fatty tissues, lungs, and kidneys
## Footnote
The liver can accumulate vitamin A reserves that can last up to a year.
108
What is the maximum amount of vitamin A the liver can store?
Up to a year's supply
## Footnote
This storage capacity allows the body to maintain adequate levels of vitamin A during periods of low intake.
109
In what form is vitamin A primarily stored in the body?
As retinyl esters
## Footnote
Retinyl esters are formed by esterifying the C-15 alcohol group of retinol with a fatty acid.
110
What type of fatty acid is usually involved in the formation of retinyl esters?
Usually a long-chain aliphatic acid, such as palmitic acid
## Footnote
Palmitic acid is a common fatty acid that contributes to the structure of retinyl esters.
111
True or False: The liver's storage of vitamin A can be depleted within a few weeks.
False
## Footnote
The liver can store vitamin A for an extended period, up to a year.
112
Fill in the blank: The C-15 alcohol group of retinol is esterified with a _______ in retinyl esters.
fatty acid
113
What happens to vitamin A reserves in the liver as a person reaches adulthood?
They gradually accumulate and reach their peak
## Footnote
This peak accumulation is important for maintaining health and preventing deficiencies.
114
What kind of cells in the retina are responsible for light sensitivity?
Rods and cones
## Footnote
Rods are responsible for vision in dim light, while cones are responsible for color vision.
115
What is the role of retinal in rod cells?
Combines with opsin to form rhodopsin
## Footnote
Rhodopsin is necessary for seeing in dim light.
116
What is the visual pigment involved in cone cells?
Iodopsin
## Footnote
Iodopsin is formed by photopsin and retinal.
117
What process occurs when light hits the rods?
Somerization of 11-cis-retinal into all-trans-retinal
## Footnote
This process leads to the bleaching of rhodopsin.
118
What triggers the cascade of the second messenger system in vision?
Metarhodopsin activates transducin
## Footnote
This leads to a cyclic guanosine monophosphate (GMP) cascade.
119
Fill in the blank: Light enters the eye and passes through the _______ before hitting the retina.
Cornea
120
True or False: Rods are primarily responsible for color vision.
False
## Footnote
Rods are responsible for vision in low light, while cones are responsible for color vision.
121
What is rhodopsin?
A visual pigment formed from retinal and opsin
## Footnote
It is essential for dim light vision.
122
What happens during the 'bleaching' process in the visual cycle?
Conformational changes in opsin occur
## Footnote
This is triggered by the somerization of retinal.
123
What is the function of rods and cones in the visual system?
Convert light into a nerve signal
## Footnote
This allows the brain to process visual information.
124
What is the function of vitamin A in cell differentiation?
Vitamin A is required to turn on cell differentiation of many cells by reacting with receptor sites on cell surface.
## Footnote
Cell differentiation is the process by which stem cells develop into highly specific types of cells with unique functions.
125
What is retinoic acid's role in the immune system?
Retinoic acid is needed to replace epithelial cells, which are vital to the immune system.
## Footnote
Epithelial cells are the millions of cells that cover and protect external and internal surfaces of the body.
126
What type of cells do some epithelial cells differentiate into?
Some epithelial cells differentiate into mucous-secreting cells known as goblet cells.
## Footnote
Goblet cells provide lubrication along the gastrointestinal tract.
127
What are epithelial tissues?
Epithelial tissues, such as skin and mucous membranes, are the first line of defense against bacteria, parasites, and viruses.
## Footnote
Epithelial cells protect the body and are destroyed and replaced very quickly.
128
True or False: Epithelial cells are static and do not change.
False
## Footnote
Epithelial cells are rapidly destroyed and replaced, contributing to their dynamic nature.
129
Fill in the blank: Retinoic acid reacts with receptor sites on a cell's _______.
DNA
## Footnote
This interaction is crucial for the regulation of gene expression during cell differentiation.
130
What are the functions of vitamin A?
Supports reproduction, bone growth, and remodeling
## Footnote
In men, it supports sperm production; in women, it maintains fertility.
131
How does a lack of vitamin A affect bones?
Increases bone loss and risk for fractures
## Footnote
Lack of vitamin A causes bones to weaken and disrupts bone remodeling.
132
What is the effect of excess vitamin A on calcium absorption?
Interferes with the ability of vitamin D to promote calcium absorption.
133
What role do retinol and retinal play in the body?
Support reproduction.
134
How does a lack of vitamin A affect growing children?
Disrupts bone remodeling and interferes with the development of immature bone cells, resulting in weak, poorly formed bones.
135
What are the sources of vitamin A?
Animal food sources (retinoids), plant food sources (provitamin A carotenoids), fortified foods.
136
What are examples of fortified foods that contain vitamin A?
Margarine, some breakfast cereals, reduced-fat milks.
137
True or False: Vitamin A is only found in animal food sources.
False.
138
Fill in the blank: The plant food sources of vitamin A are known as _______.
provitamin A carotenoids.
139
What type of vitamin is vitamin A classified as?
Fat soluble vitamin.
140
What is the most active form of vitamin A?
Retinol
141
What are dietary sources of preformed vitamin A?
* Fish liver oils
* Some fatty fish
* Liver and liver products
* Fortified margarine and fat spreads
* Fortified skimmed dried milk
142
What percentage of dietary retinoids does the body absorb?
75%
143
What is the composition of vitamin A found in animal foods?
10% in the form of retinal, 90% retinyl esters
144
True or False: Preformed vitamin A is only found naturally in animal foods.
True
145
Fill in the blank: The most natural form of vitamin A is found in _______.
Fish liver oils
146
What is the most important provitamin A carotenoid?
Beta carotene
## Footnote
Beta carotene is converted into retinol in the body and is a crucial source of Vitamin A.
147
List three other provitamin A carotenoids besides beta carotene.
* Alpha carotene
* Beta-cryptoxanthin
* Lutein
* Lycopene
## Footnote
These carotenoids contribute to Vitamin A intake from dietary sources.
148
Which vegetables are most abundant in carotenes?
* Broccoli
* Spinach
* Sweet potatoes
* Pumpkin
* Squash
* Carrots
* Red peppers
* Tomatoes
## Footnote
These vegetables are rich in carotenes, which are important for Vitamin A.
149
Name two types of fruits that are good sources of provitamin A carotenoids.
* Apricots
* Peaches
* Mango
## Footnote
Orange/yellow fruits are significant sources of carotenoids.
150
Fill in the blank: Some plant oils, such as ______, are the richest sources of provitamin A known.
[palm]
## Footnote
Palm oil is recognized for its high content of carotenoids.
151
What are the main contributors of total vitamin A (retinol & carotenoids) to the UK diet?
* Meat and meat products (primarily from liver and products containing it) - 28%
* Vegetables (excluding potatoes) - 27%
* Milk, milk products & cheese - 14%
* Fat spreads - 10%
* Cooked carrots provide ~ 30% total carotene intake amongst UK adults - 25%
152
What percentage of total vitamin A intake comes from meat and meat products?
28%
153
What percentage of total vitamin A intake comes from vegetables (excluding potatoes)?
27%
154
What is the contribution of milk, milk products, and cheese to total vitamin A intake?
14%
155
What percentage of total vitamin A intake is attributed to fat spreads?
10%
156
Cooked carrots provide approximately what percentage of total carotene intake among UK adults?
30%
157
What is the definition of 1 retinol activity equivalent (RAE)?
1 RAE = 1 ug retinol
## Footnote
RAE is used to develop dietary recommendations for Vitamin A.
158
How many micrograms of retinol are equivalent to 2 micrograms of supplemental beta-carotene?
2 ug supplemental beta-carotene = 1 RAE
## Footnote
This highlights the conversion of beta-carotene to active Vitamin A.
159
What is the conversion of 1 RAE to dietary beta-carotene?
1 RAE = 12 mg dietary beta-carotene
## Footnote
This shows the amount of dietary beta-carotene needed for the equivalent of 1 RAE.
160
What is the conversion of 1 RAE to dietary carotenoids?
1 RAE = 24 mg dietary carotenoids
## Footnote
This indicates the amount of dietary carotenoids for 1 RAE.
161
True or False: Similar quantities of dietary retinoids and carotenoids provide the same amount of active vitamin A.
False
## Footnote
Retinoids and carotenoids do not provide the same amount of active Vitamin A.
162
What is the recommended intake of Vitamin A for males over 15 years?
300 ng RE / day
## Footnote
RE stands for Retinol Equivalents
163
What is the recommended intake of Vitamin A for females over 15 years?
250 ng RE / day
## Footnote
RE stands for Retinol Equivalents
164
What is the LRNI for males over 15 years in terms of Vitamin A?
500 ug RE / day
## Footnote
LRNI stands for Lower Reference Nutrient Intake
165
What is the EAR for females over 15 years in terms of Vitamin A?
400 ug RE / day
## Footnote
EAR stands for Estimated Average Requirement
166
What is the RNI for males over 15 years in terms of Vitamin A?
700 ug RE / day
## Footnote
RNI stands for Reference Nutrient Intake
167
What is the RNI for females over 15 years in terms of Vitamin A?
600 ug RE / day
## Footnote
RNI stands for Reference Nutrient Intake
168
What is Vitamin A deficiency?
A condition resulting from inadequate Vitamin A intake.
## Footnote
It is a leading cause of child blindness worldwide.
169
Is Vitamin A deficiency common in North America and Western Europe?
No, it is rare in these regions.
170
What is a leading cause of child blindness worldwide?
Vitamin A deficiency.
171
What health issues are often associated with Vitamin A deficiency?
Protein-energy malnutrition.
172
What are the effects of Vitamin A deficiency on the body?
Affects eyes, body cell development, and immune function.
173
Who is at risk of Vitamin A deficiency?
* Newborns
* The impoverished
* People with alcoholism
* Individuals with liver disease or fat mal-absorption conditions.
174
Fill in the blank: Vitamin A deficiency is a leading cause of _______.
child blindness.
175
True or False: Vitamin A deficiency is common among the general population in developed countries.
False.
176
What can vitamin A deficiency lead to?
Night blindness, xerophthalmia, keratinisation of epithelial tissues, increased susceptibility to infection.
177
Why are young children especially vulnerable to vitamin A deficiency?
Night blindness is an early symptom of deficiency, which can be completely corrected with early treatment.
178
What is xerophthalmia?
Symptoms that progress toward blindness, including abnormal dryness of the conjunctiva and cornea, inflammation, and ridge formation.
179
What is an early sign of vitamin A deficiency?
Dark adaptation, which relates to the speed of adjusting to dim light.
180
What is Xerophthalmia?
Progressive nutritional disease of the eye.
## Footnote
Xerophthalmia is often associated with a deficiency in Vitamin A.
181
What effect does a lack of retinoic acid have on epithelial cells?
Interferes with normal differentiation of epithelial cells.
## Footnote
Retinoic acid is crucial for maintaining the health and function of epithelial tissues.
182
What is corneal xerosis?
Condition where cornea and conjunctiva become dry, thickened, and wrinkled.
## Footnote
This is a direct result of Vitamin A deficiency.
183
What are Bitot's spots?
Cheesy, white spots that appear on the conjunctiva.
## Footnote
Bitot's spots are indicative of Vitamin A deficiency.
184
What is keratomalacia?
Erosion of the cornea characterized by softening and destruction.
## Footnote
Keratomalacia occurs due to a severe deficiency of Vitamin A.
185
What happens when there is a lack of mucus in the eye?
Prevents washing away of dirt and bacteria, increasing likelihood of infection.
## Footnote
Mucus plays a vital role in protecting the eye from pathogens.
186
What is the effect of Vitamin A deficiency on skin?
Skin becomes hard and scaly
## Footnote
This is due to a lack of retinoic acid which shifts differentiation of epithelial cells toward becoming skin cells.
187
What condition is characterized by 'goose flesh'?
Hyperkeratosis
## Footnote
Hyperkeratosis is a condition resulting from Vitamin A deficiency.
188
How does Vitamin A deficiency affect sweat glands?
Reduces ability to secrete perspiration
## Footnote
This impaired function is a result of the deficiency affecting epithelial cells.
189
What is disrupted in other epithelial cells due to Vitamin A deficiency?
Ability to secrete mucus
## Footnote
This disruption can lead to various complications in bodily functions.
190
What effect does Vitamin A deficiency have on men specifically?
Stops production of certain substances
## Footnote
This can include reproductive hormones or other critical secretions.
191
What is a consequence of Vitamin A deficiency?
Immune function impairment
## Footnote
Vitamin A is crucial for maintaining a healthy immune system.
192
How does Vitamin A deficiency affect susceptibility to infections?
Increases vulnerability to infection
## Footnote
Deficiencies weaken the body's defenses.
193
What happens to the epithelium in Vitamin A deficiency?
It becomes damaged, allowing microorganisms to breach the first line of defense
## Footnote
A healthy epithelium is essential for preventing infections.
194
What do immune cells require to multiply effectively?
Vitamin A
## Footnote
Adequate Vitamin A levels are necessary for proper immune cell function.
195
What severe health issues can Vitamin A deficiency cause?
Severe diarrhea or respiratory infection
## Footnote
These conditions can be life-threatening, especially in vulnerable populations.
196
What is a consequence of Vitamin A deficiency?
Immune function impairment
## Footnote
Vitamin A is crucial for maintaining a healthy immune system.
197
How does Vitamin A deficiency affect susceptibility to infections?
Increases vulnerability to infection
## Footnote
Deficiencies weaken the body's defenses.
198
What happens to the epithelium in Vitamin A deficiency?
It becomes damaged, allowing microorganisms to breach the first line of defense
## Footnote
A healthy epithelium is essential for preventing infections.
199
What do immune cells require to multiply effectively?
Vitamin A
## Footnote
Adequate Vitamin A levels are necessary for proper immune cell function.
200
What severe health issues can Vitamin A deficiency cause?
Severe diarrhea or respiratory infection
## Footnote
These conditions can be life-threatening, especially in vulnerable populations.
201
What is the potential risk associated with Vitamin A toxicity?
Potential increases with use of supplements
## Footnote
Vitamin A toxicity can lead to serious health issues.
202
Why are pregnant women advised to avoid eating pate during pregnancy?
Vitamin A can be teratogenic - cause fetal abnormalities
## Footnote
Certain foods like liver pate contain high levels of Vitamin A.
203
What type of Vitamin A supplements should pregnant women use?
Use prenatal supplements with beta-carotene, not retinol
## Footnote
Beta-carotene is a safer alternative during pregnancy.
204
Fill in the blank: Vitamin A can be _______ - cause fetal abnormalities.
teratogenic
## Footnote
Teratogenic substances can affect fetal development.
205
True or False: Pregnant women can safely consume liver pate.
False
## Footnote
Liver pate is high in Vitamin A, which can be harmful during pregnancy.
206
What is Vitamin A commonly prescribed for?
Acne treatment
## Footnote
Vitamin A is often used in the form of retinoic acid for treating acne.
207
What can contribute to Vitamin A toxicity?
Retinoic acid
## Footnote
Retinoic acid is a common treatment for acne but can lead to toxicity if not managed properly.
208
When should retinoic acid be stopped before pregnancy?
At least 2 years before becoming pregnant
## Footnote
It is important to stop retinoic acid to prevent potential harm during pregnancy.
209
True or False: Vitamin A should be taken during pregnancy.
False
## Footnote
Vitamin A, particularly in the form of retinoic acid, should not be taken during pregnancy.
210
Fill in the blank: _______ is a common form of retinoic acid prescribed for acne.
Tretinoin
## Footnote
Tretinoin is often marketed under the brand name Retin-A.
211
What are carotenoids?
Plant pigments
## Footnote
Carotenoids are organic pigments found in plants, responsible for the yellow, orange, and red colors in many fruits and vegetables.
212
Name three provitamin A carotenoids.
* Alpha-carotene
* Beta-carotene
* Cryptoxanthin
## Footnote
Provitamin A carotenoids can be converted into vitamin A in the body.
213
Which provitamin A carotenoid is the most common?
Beta-carotene
## Footnote
Beta-carotene is widely recognized for its role in vitamin A synthesis and is abundant in carrots and sweet potatoes.
214
List two nonprovitamin A carotenoids.
* Lutein
* Zeaxanthin
* Lycopene
## Footnote
Nonprovitamin A carotenoids do not convert to vitamin A and are known for their antioxidant properties.
215
True or False: Lutein is a provitamin A carotenoid.
False
## Footnote
Lutein is classified as a nonprovitamin A carotenoid.
216
Fill in the blank: The most common carotenoid is _______.
Beta-carotene
## Footnote
Beta-carotene is not only the most prevalent carotenoid but also a significant source of vitamin A.
217
What are carotenoids?
Carotenoids are pigments found in plants that can function as potent antioxidants.
218
Are carotenoids considered essential nutrients?
No, carotenoids are not technically essential.
219
List three functions of carotenoids.
* Can function as potent antioxidants
* Help immune function
* Protect vision
220
How do carotenoids lower the risk of certain cancers?
They help fight oxidative damage associated with ageing.
221
What is oxidative damage?
Oxidative damage is caused by free radicals, which can damage the structure and function of cell membranes through oxidation.
222
What role does beta-carotene play in health?
Beta-carotene protects against age-associated diseases such as cancer, atherosclerosis, and diabetes.
223
True or False: Lycopene is found in tomatoes.
True
224
What are carotenoids?
Carotenoids are pigments found in plants that contribute to their color and have health benefits.
225
What percentage of carotenoids eaten does the body absorb?
20-40%
226
How does the absorption of carotenoids change with increased consumption?
The proportion of carotenoids absorbed drops as you consume more.
227
What dietary components enhance the absorption of carotenoids?
Dietary fat, protein, and vitamin E
228
Where are carotenoids primarily stored in the body?
Liver and adipose tissues
229
Fill in the blank: The body absorbs _____% of carotenoids eaten.
20-40%
230
True or False: The absorption of carotenoids increases with higher consumption.
False
231
What role does dietary fat play in carotenoid absorption?
Enhances absorption
232
List the primary storage depots for carotenoids in the body.
* Liver
* Adipose tissues
233
What are carotenoids?
Carotenoids are pigments found in plants that contribute to the orange, yellow, and green colors in fruits and vegetables.
234
What are good sources of carotenoids?
Good sources include:
* Orange and yellow fruits
* Dark green vegetables
235
How does chopping and cooking affect carotenoid absorption?
Chopping and cooking helps release carotenoids and makes them easier to absorb.
236
What is the current evidence regarding carotenoid supplementation?
The evidence for protection against cancer and heart disease from supplementation is not clear.
237
What is the recommended way to consume carotenoids?
The advice is to consume carotenoids via food.
238
Fill in the blank: Good sources of carotenoids include orange and yellow fruits and _______.
dark green vegetables.
239
True or False: Cooking carotenoid-rich foods does not affect their absorption.
False
240
What vitamin is synthesized and functions like a hormone?
Vitamin D
## Footnote
Vitamin D is synthesized in the body with regular exposure to sunlight.
241
Is vitamin D always necessary in the diet?
No
## Footnote
The body can produce sufficient vitamin D with adequate sunlight exposure.
242
What essential role does vitamin D play in the body?
Essential for bone health
## Footnote
Vitamin D helps in the development and maintenance of bones.
243
What nickname is given to vitamin D due to its synthesis from sunlight?
Sunshine hormone
## Footnote
This term reflects its ability to be produced when skin is exposed to sunlight.
244
What is the effect of sufficient sunlight on the body's vitamin D needs?
Can completely meet body's needs
## Footnote
Adequate sunlight exposure allows the body to synthesize enough vitamin D.
245
What role does vitamin D play in children's health?
Promotes bone development and growth
## Footnote
Vitamin D is crucial for the proper growth of bones in children.
246
How does vitamin D affect adults in terms of bone health?
Necessary for bone maintenance
## Footnote
Adults require vitamin D to maintain their bone density and strength.
247
What is the benefit of vitamin D and calcium supplementation for the elderly?
Helps prevent bone loss and fractures
## Footnote
Supplementation is important for maintaining bone health in older adults.
248
What is Vitamin D considered?
A vitamin or a hormone
## Footnote
Vitamin D regulates activities in various parts of the body, similar to hormones.
249
How many compounds exhibit antirachitic properties related to Vitamin D?
Ten compounds
## Footnote
Antirachitic properties help prevent childhood bone disease, specifically rickets.
250
What are the two most important forms of Vitamin D?
D2 (ergocalciferol) and D3 (cholecalciferol)
## Footnote
D2 is found only in plant sources, while D3 is found in animal foods.
251
How is Vitamin D made in the body?
Made in the skin from cholesterol
## Footnote
This process involves the conversion of cholesterol to Vitamin D when exposed to sunlight.
252
Where is Vitamin D activated in the body?
In the liver and kidney
## Footnote
Activation is necessary for Vitamin D to perform its regulatory functions.
253
What condition does Vitamin D help prevent in children?
Rickets
## Footnote
Rickets causes bones to become soft and weak, leading to deformities.
254
What precursor derived from cholesterol is converted into cholecalciferol when UV rays strike the skin?
7-dehydrocholesterol
255
What is the role of the liver in vitamin D metabolism?
Converts cholecalciferol and ergocalciferol into calcidiol and sends it to kidneys
256
What is formed in the kidneys from calcidiol?
Calcitriol
257
During which months does no vitamin D synthesis occur in the UK?
October - March
258
True or False: UV radiation can penetrate light cloud and thin clothing.
True
259
How does the liver receive vitamin D besides synthesis?
From chylomicrons from dietary vitamin D
260
Fill in the blank: The skin converts _______ into cholecalciferol when exposed to UV rays.
7-dehydrocholesterol
261
What does the kidneys activate vitamin D into?
Calcitriol
262
Why is vitamin D synthesis not possible in the UK from October to March?
Light of the correct wavelength does not reach the earth's surface
263
What is a primary function of Vitamin D?
Regulation of blood calcium levels
## Footnote
Vitamin D plays a crucial role in maintaining calcium homeostasis in the body.
264
Name a function of Vitamin D related to cell activity.
Regulation of cell differentiation and growth
## Footnote
This function is important for normal cellular function and development.
265
What role does Vitamin D play in cancer prevention?
Prevention of cancer cell division
## Footnote
Vitamin D may help inhibit the proliferation of cancer cells.
266
List an anti-inflammatory property of Vitamin D.
Anti-inflammatory properties
## Footnote
Vitamin D can help modulate the immune response and reduce inflammation.
267
How does Vitamin D affect insulin?
Regulation of insulin formation and secretion
## Footnote
This function is significant for glucose metabolism and overall metabolic health.
268
What was the mean intake of vitamin D for adults aged 65 to 74 years?
35% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
269
What was the mean intake of vitamin D for adults aged 75 years and over?
28% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
270
What was the mean intake of vitamin D when dietary supplements were included for adults aged 65 to 74 years?
60% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
271
What was the mean intake of vitamin D when dietary supplements were included for adults aged 75 years and over?
53% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
272
What difficulty is associated with quantifying dietary requirements for vitamin D?
Endogenous production cannot be measured
273
Until what year was there no UK recommended intake for those aged 6 - 64 years?
2016
274
What is the updated RNI for vitamin D established by SACN in 2016 for the general population?
10 µg/day
275
What is the RNI for vitamin D for children under 12 months?
8.5 - 10 µg/day
276
For which groups is vitamin D particularly important?
* Children
* Pregnant women
* Lactating women
* Older adults
277
What assumption was made regarding dietary sources of vitamin D for those aged 6 - 64 years before 2016?
Adequate dietary sources and sun exposure
278
True or False: The mean intake of vitamin D in older age groups is above the RNI.
False
279
What was the mean intake of vitamin D for adults aged 65 to 74 years?
35% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
280
What was the mean intake of vitamin D for adults aged 75 years and over?
28% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
281
What was the mean intake of vitamin D when dietary supplements were included for adults aged 65 to 74 years?
60% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
282
What was the mean intake of vitamin D when dietary supplements were included for adults aged 75 years and over?
53% of the RNI
## Footnote
RNI stands for Reference Nutrient Intake
283
What difficulty is associated with quantifying dietary requirements for vitamin D?
Endogenous production cannot be measured
284
Until what year was there no UK recommended intake for those aged 6 - 64 years?
2016
285
What is the updated RNI for vitamin D established by SACN in 2016 for the general population?
10 µg/day
286
What is the RNI for vitamin D for children under 12 months?
8.5 - 10 µg/day
287
For which groups is vitamin D particularly important?
* Children
* Pregnant women
* Lactating women
* Older adults
288
What assumption was made regarding dietary sources of vitamin D for those aged 6 - 64 years before 2016?
Adequate dietary sources and sun exposure
289
True or False: The mean intake of vitamin D in older age groups is above the RNI.
False
290
What association was found between vitamin D status and COVID-19 according to some studies?
A lower vitamin D status and subsequent development of COVID-19
## Footnote
Some studies did not adjust for confounders such as obesity and underlying health conditions.
291
What did one study conclude about the causal association between vitamin D status and COVID-19?
No causal association after adjustment of confounding factors
## Footnote
Adjustments included comorbidity and ethnicity.
292
What confounders were not adjusted in studies linking vitamin D to COVID-19?
* Obesity
* Underlying health conditions
## Footnote
These confounders may affect the validity of the results.
293
True or False: All studies found a direct causal link between vitamin D status and COVID-19.
False
## Footnote
Some studies did not find a causal association after adjustments.
294
What is the minimum sunlight exposure needed for fair-skinned individuals to produce vitamin D?
As little as 15 minutes a day
295
How many hours of sunlight exposure may be needed for individuals with darker skin to produce vitamin D?
A few hours a day
296
What factors influence the exact amount of sun exposure required to produce vitamin D?
* Time of day
* Season
* Location
* Sunscreen use
* Skin type
297
True or False: A fair-skinned person can produce as much vitamin D in a day with just 15 minutes of sunlight.
True
298
Fill in the blank: The amount of sun exposure needed to produce vitamin D varies based on _______.
[multiple factors like time, season, location, sunscreen use, skin type]
299
What are natural dietary sources of Vitamin D?
Oily fish, cod liver oil, meat (particularly liver), milk and dairy products, eggs
## Footnote
Oily fish examples include salmon, herring, and sardines.
300
What foods are often fortified with Vitamin D?
Fat spreads, breakfast cereals, evaporated milk, skimmed milk powder, yoghurts, infant food
## Footnote
Fortification is the process of adding nutrients to foods.
301
When are levels of Vitamin D higher in dairy products?
Summer months
## Footnote
Seasonal variations can affect nutrient levels in food.
302
What is a rich source of Vitamin D besides food?
Calcium supplements
## Footnote
Some calcium supplements are fortified with Vitamin D to enhance absorption.
303
Is UK milk normally fortified with Vitamin D?
No
## Footnote
This is a notable difference compared to some other countries where milk is commonly fortified.
304
Fill in the blank: Oily fish includes salmon, herring, and _______.
sardines
## Footnote
These fish are known for their high Vitamin D content.
305
True or False: Eggs are a significant source of Vitamin D.
True
## Footnote
The yolk of eggs contains Vitamin D, but levels can vary.
306
What types of meat are particularly high in Vitamin D?
Liver
## Footnote
Liver from various animals is a good source of many vitamins, including Vitamin D.
307
What percentage of adults had low vitamin D status over the whole year?
17%
## Footnote
Low vitamin D status is indicated by low plasma 25-hydroxy vitamin D concentrations in blood.
308
What percentage of older adults had low vitamin D status over the whole year?
13%
## Footnote
This indicates a significant concern for vitamin D deficiency among the elderly.
309
What percentage of 11-18 year-old children had low vitamin D status over the whole year?
26%
## Footnote
This highlights the prevalence of vitamin D deficiency in adolescents.
310
Which groups in the UK may be at a higher risk of vitamin D deficiency?
* Exclusively breastfed infants
* Elderly
* Residing in very North of UK
* Obese
## Footnote
These groups are particularly vulnerable due to various factors affecting vitamin D synthesis and intake.
311
What is the recommendation for vitamin D intake due to inadequate levels?
Supplements now recommended
## Footnote
This recommendation is made because intakes do not generally meet the Reference Nutrient Intake (RNI).
312
What is the estimated percentage of people from Western society with inadequate blood levels of vitamin D?
Up to 80%
## Footnote
This statistic suggests a widespread issue of vitamin D deficiency in these populations.
313
What factors may contribute to low vitamin D levels in Western society?
* Increase in obesity
* Decrease in milk consumption
* Increase use of sunscreen
## Footnote
These lifestyle changes can significantly impact vitamin D synthesis and absorption.
314
Why are exclusively breastfed infants at risk for vitamin D deficiency after 9 months?
Breast milk contains very little vitamin D
## Footnote
Infants must obtain vitamin D through sunlight, formula, or supplements after their initial stores are depleted.
315
How does age affect the ability to synthesize vitamin D from sunlight?
Adults older than 70 have a 4-fold reduction in ability
## Footnote
This significant reduction increases the risk of vitamin D deficiency in older adults.
316
How does living further north affect vitamin D synthesis in winter?
Daylight hours are short and sunlight strength is weak
## Footnote
This results in halted vitamin D synthesis during winter months.
317
What is the relationship between BMI and active vitamin D levels?
Inverse relationship
## Footnote
Higher body mass index (BMI) may trap vitamin D in subcutaneous adipose tissue, reducing its circulation.
318
Which other groups may be at risk for vitamin D deficiency?
* Patients with fat malabsorption
* People with dark skin
## Footnote
These groups face additional challenges in synthesizing or absorbing sufficient vitamin D.
319
What is the result of prolonged deficiency of vitamin D?
Demineralisation and 'softening' of the bones
## Footnote
This condition leads to Rickets in children and Osteomalacia in adults.
320
What condition results from vitamin D deficiency in children?
Rickets
## Footnote
Rickets is characterized by the softening of bones in children due to a lack of vitamin D.
321
What condition results from vitamin D deficiency in adults?
Osteomalacia
## Footnote
Osteomalacia leads to progressive decalcification of bone.
322
What may happen if treatment with vitamin D is not given for osteomalacia?
Condition may become irreversible
## Footnote
Without treatment, the softening and weakening of bones can persist.
323
What has contributed to the decline of rickets in the US?
Vitamin D-fortified milk and infant vitamin supplements
## Footnote
These interventions have helped improve vitamin D levels in the population.
324
What are common symptoms of osteomalacia?
Bone pain, muscular weakness, tetany, spontaneous fractures, bowing of the spine, difficulty walking
## Footnote
Symptoms may include a waddling gait.
325
Which organs are involved with the absorption and activation of vitamin D?
Kidneys, liver, intestines
## Footnote
These organs play a critical role in the metabolism of vitamin D.
326
True or False: Vitamin D deficiency symptoms include spontaneous fractures.
True
## Footnote
Spontaneous fractures are a significant symptom of osteomalacia.
327
Fill in the blank: Prolonged deficiency of vitamin D leads to _______ and softening of the bones.
Demineralisation
328
What is osteoporosis often referred to as?
'Porous bone'
## Footnote
Osteoporosis is characterized by decreased bone density and quality, leading to increased fracture risk.
329
What vitamin deficiency can lead to osteoporosis?
A lack of vitamin D
## Footnote
Vitamin D is essential for calcium absorption and bone health.
330
What factors can influence osteoporosis?
Lifestyle
## Footnote
Factors such as diet, exercise, and smoking can impact bone health.
331
What effect do vitamin D supplements have on elderly women?
Slows bone turnover, increases bone density, reduces falls, and decreases nonvertebral fractures
## Footnote
Vitamin D is often taken in combination with calcium for enhanced effects.
332
What can cause vitamin D toxicity?
Infant supplementation or replacement treatment for osteomalacia
## Footnote
Vitamin D toxicity can occur when excess vitamin D is administered.
333
What is a symptom of vitamin D toxicity related to calcium levels?
High levels of calcium in blood (hypercalcemia)
## Footnote
Hypercalcemia can lead to various health issues.
334
What are the consequences of hypercalcemia due to vitamin D toxicity?
* Soft tissue calcification
* Demineralisation of bones
* Renal toxicity
* Cardiovascular toxicity
* Central nervous system effects
## Footnote
These consequences indicate serious health risks associated with excessive vitamin D.
335
True or False: Vitamin D given in milligram amounts is lethal.
True
## Footnote
This highlights the potential danger of overdosing on vitamin D.
336
What are the two sets of compounds that form Vitamin E?
The tocopherols and tocotrienols
## Footnote
These compounds are essential for understanding the different forms of Vitamin E.
337
Which form of tocopherol is considered for human Vitamin E requirements?
Only alpha-tocopherol
## Footnote
Alpha-tocopherol is the most biologically active form of Vitamin E.
338
What is the absorption rate of Vitamin E in the GI tract?
20-80%
## Footnote
This indicates the efficiency of Vitamin E absorption in the digestive system.
339
Where is Vitamin E mainly stored in the body?
In adipose tissue
## Footnote
Adipose tissue serves as the primary storage site for fat-soluble vitamins.
340
Does Vitamin E accumulate in the liver?
No
## Footnote
Unlike some other vitamins, Vitamin E does not accumulate in the liver.
341
List the four tocopherols.
* Alpha-tocopherol
* Beta-tocopherol
* Gamma-tocopherol
* Delta-tocopherol
## Footnote
These are the different forms of tocopherols found in Vitamin E.
342
List the four tocotrienols.
* Alpha-tocotrienol
* Beta-tocotrienol
* Gamma-tocotrienol
* Delta-tocotrienol
## Footnote
Tocotrienols are another group of compounds that constitute Vitamin E.
343
Fill in the blank: Only _______ contributes to meeting Vitamin E requirements.
alpha-tocopherol
## Footnote
This highlights the specificity of the Vitamin E requirement in humans.
344
What is the most common form of Vitamin E in food?
Alpha-tocopherol
## Footnote
This form is prevalent in various dietary sources of Vitamin E.
345
What are free radicals?
Highly unstable, toxic molecules containing an unpaired electron
346
What makes free radicals highly reactive?
The presence of unpaired electrons
347
How do free radicals affect healthy cells?
They steal electrons from healthy cells, turning them into free radicals
348
What process generates free radicals in the body?
Normal metabolic processes where oxygen reacts with other compounds
349
Fill in the blank: Free radicals create a chain reaction by stealing electrons, which produces a flood of _______.
free radicals
350
True or False: Free radicals can only be generated through external environmental factors.
False
351
What happens to a compound when it is attacked by a free radical?
It loses an electron and becomes a free radical itself
352
What is the consequence of a free radical stealing an electron from a healthy cell?
The healthy cell becomes a free radical
353
List three characteristics of free radicals.
* Highly unstable
* Toxic
* Contain an unpaired electron
354
What role does Vitamin E play as an antioxidant?
Interrupts cascade of free radical formation
## Footnote
Vitamin E donates electrons to neutralize free radicals, thus preventing cellular damage.
355
What happens to Vitamin E when it interrupts free radical formation?
Vitamin E becomes a free radical
## Footnote
This process involves the transfer of electrons, which can lead to further reactions.
356
Which vitamin donates an electron to Vitamin E?
Vitamin C
## Footnote
Vitamin C helps regenerate Vitamin E by donating an electron.
357
What molecule donates an electron to Vitamin C?
Glutathione
## Footnote
Glutathione plays a key role in the antioxidant system by donating electrons.
358
What restores glutathione to its active form?
Glutathione reductase
## Footnote
This enzyme is crucial for maintaining the antioxidant capacity of glutathione.
359
Fill in the blank: Unpaired electrons can lead to _______.
Free radicals
## Footnote
Free radicals can cause oxidative stress and damage cellular components.
360
True or False: Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are beneficial for the host defense system.
True
## Footnote
ROS and RNS are involved in the maturation of cellular structures and immune responses.
361
What type of cells release free radicals to destroy invading pathogens?
Phagocytes
## Footnote
Phagocytes, including neutrophils and monocytes, use free radicals as part of the immune defense mechanism.
362
What is glutathione made up of?
Three amino acids
## Footnote
Glutathione consists of glutamine, cysteine, and glycine.
363
What is the role of NADPH in glutathione function?
Provides electrons for converting glutathione into its antioxidant form
## Footnote
NADPH is essential for the regeneration of glutathione.
364
What do free radicals attack in cells?
Membranes and cell constituents, including DNA
## Footnote
This attack can lead to cellular dysfunction and disease.
365
What is a free radical?
An unstable molecule that can cause damage to cells
366
What role does Vitamin E play in relation to free radicals?
Vitamin E donates an electron to a free radical, lowering its damage potential to membrane molecules
367
What is lipid peroxidation?
A form of free radical damage involving oxidative degradation of lipids
368
What are the effects of lipid peroxidation?
Produces unstable, highly reactive lipid molecules called peroxides
369
Which type of lipids are commonly affected by lipid peroxidation?
Lipid molecules with carbon-carbon double bonds, such as polyunsaturated fatty acids
370
How does Vitamin E help protect cell membranes?
By acting as an antioxidant to prevent free radical damage
371
True or False: Lipid peroxidation can promote atherosclerosis.
True
372
In which cellular structures are lipid molecules abundant, making them susceptible to lipid peroxidation?
Cell membranes
373
Fill in the blank: Lipid peroxidation involves the _______ of lipids.
oxidative degradation
374
What happens to electrons during oxidative degradation?
They are lost, as they are stolen from free radicals
375
What is one function of Vitamin E?
Protects white blood cells
## Footnote
This function enhances immunity.
376
How does Vitamin E relate to Vitamin A?
It aids in the absorption of vitamin A
## Footnote
This is crucial for maintaining healthy vision.
377
What roles does Vitamin E play in nerve and muscle health?
Critical for development and maintenance
## Footnote
This indicates its importance in neuromuscular function.
378
What newer studies link Vitamin E to?
Neurological function protection
## Footnote
This suggests a potential role in preventing neurodegenerative diseases.
379
List additional functions of Vitamin E.
* Cell proliferation
* Circulatory system functions
* Prevention of menopausal symptoms
* Cancer protection
## Footnote
These functions highlight its broad health benefits.
380
True or False: Vitamin E activity is enhanced by other antioxidants.
True
## Footnote
Examples of such antioxidants include Vitamin C and selenium.
381
Fill in the blank: Vitamin E is critical for the development and maintenance of _______.
[nerves and muscles]
382
What is Vitamin E classified as?
An antioxidant
383
How are Vitamin E requirements determined?
By the amount of PUFA in the body and thus the PUFA content of the diet
384
Why do PUFA increase the need for Vitamin E?
PUFA have many unsaturated double bonds which are more susceptible to oxidation
385
What is the relationship between PUFA and antioxidants?
More PUFA = greater need for protection against oxidation and greater need for antioxidants like Vitamin E
386
What is the average UK intake of Vitamin E?
~6mg/day
387
Why was it not possible for the panel to set DRVs for Vitamin E?
PUFA intake varies widely
388
What are the estimations for Vitamin E intake based on PUFA consumption?
0.4 - 0.6mg/g of PUFA
389
How does PUFA intake affect Vitamin E requirements?
The higher the PUFA intake, the higher the vitamin E requirement
390
What are the safe intake levels of Vitamin E for men?
>4mg
391
What are the safe intake levels of Vitamin E for women?
>3mg
392
What are the most concentrated sources of Vitamin E?
Vegetable oils, particularly safflower, cottonseed & sunflower seed oils
## Footnote
These oils are rich in n-6 PUFAs and also have a high content of vitamin E.
393
Which nuts and seeds are good sources of Vitamin E?
Almonds, peanuts, hazelnuts
## Footnote
These nuts and seeds provide significant amounts of vitamin E.
394
What types of manufactured products contain Vitamin E?
Margarine and salad dressings made from vegetable and seed oils
## Footnote
The amounts of vitamin E in these products can vary.
395
Do fruits and vegetables contain Vitamin E?
Yes
## Footnote
Fruits and vegetables contribute to the intake of vitamin E.
396
Are animal foods rich sources of Vitamin E?
No, animal foods are generally not rich sources
## Footnote
Small amounts of vitamin E can be found in meat, poultry, and dairy.
397
What is the rarity of Vitamin E deficiency?
Rare
398
What can lead to a functional deficiency of Vitamin E?
Severe fat malabsorption or specific genetic condition affecting vitamin E metabolism in liver
399
Name two conditions that can cause Vitamin E deficiency.
* Cystic fibrosis
* Coeliac disease
400
What is a potential consequence of Vitamin E deficiency?
Haemolysis
401
In which population is Vitamin E deficiency most often seen?
Premature infants
402
Fill in the blank: Hemolysis is the breakdown of _______.
red blood cells
403
What happens to cell membranes in the absence of Vitamin E?
Not protected against oxidation, leading to rupture
404
What syndrome is associated with fat malabsorption and Vitamin E deficiency?
Cystic fibrosis
405
What is the rarity of Vitamin E deficiency?
Rare
406
What can lead to a functional deficiency of Vitamin E?
Severe fat malabsorption or specific genetic condition affecting vitamin E metabolism in liver
407
Name two conditions that can cause Vitamin E deficiency.
* Cystic fibrosis
* Coeliac disease
408
What is a potential consequence of Vitamin E deficiency?
Haemolysis
409
In which population is Vitamin E deficiency most often seen?
Premature infants
410
Fill in the blank: Hemolysis is the breakdown of _______.
red blood cells
411
What happens to cell membranes in the absence of Vitamin E?
Not protected against oxidation, leading to rupture
412
What syndrome is associated with fat malabsorption and Vitamin E deficiency?
Cystic fibrosis
413
What are the adverse effects of vitamin E from food sources?
No adverse effects from foods rich in vitamin E
## Footnote
Vitamin E is generally safe when consumed through dietary sources.
414
What is a potential risk associated with vitamin E for individuals with vitamin K deficiency?
Increased risk of bleeding
## Footnote
Vitamin E may exacerbate bleeding risks in those with low vitamin K levels.
415
What medications may be affected by high doses of vitamin E?
Anticoagulants or aspirin
## Footnote
High doses of vitamin E can increase bleeding risks for patients taking blood thinners.
416
What can megadoses of vitamin E interfere with?
Actions of vitamin K
## Footnote
High doses of vitamin E may promote bleeding by interfering with vitamin K's functions.
417
What is the primary function of Vitamin K?
Promotes blood clotting
## Footnote
Vitamin K is essential for the synthesis of certain proteins required for blood coagulation.
418
Vitamin K is a group of compounds known as _______.
quinones
## Footnote
Quinones are a class of cyclic organic compounds that are derived from aromatic compounds.
419
Where is Vitamin K primarily stored in the body?
Liver
## Footnote
The liver is a key organ for the storage and metabolism of various nutrients, including fat-soluble vitamins.
420
How much Vitamin K is stored in the body?
Relatively small amounts
## Footnote
Due to its small storage capacity, Vitamin K must be consumed regularly through diet.
421
True or False: Vitamin K is used up rapidly in the body.
True
## Footnote
The rapid utilization of Vitamin K necessitates consistent dietary intake to maintain adequate levels.
422
What does the term 'homologous' refer to in the context of Vitamin K?
Similar/same structure
## Footnote
Homologous compounds share a similar chemical structure, which in the case of Vitamin K refers to its various forms.
423
What is the primary form of Vitamin K synthesized by plants?
Phylloquinone
## Footnote
Phylloquinone is the natural form of Vitamin K found in green leafy vegetables.
424
Which form of Vitamin K is synthesized by colonic bacteria?
Menaquinone
## Footnote
Menaquinone refers to a group of compounds with varying lengths of side chains, primarily produced by bacteria in the human gut.
425
What is the synthetic form of Vitamin K known as?
Menadione
## Footnote
Menadione is a man-made version of Vitamin K that is used in dietary supplements.
426
What is the synthetic form of Vitamin K4?
Menadiol
## Footnote
Menadiol is another synthetic derivative of Vitamin K, often used in supplements.
427
Fill in the blank: Vitamin K1 is also known as _______.
Phylloquinone
## Footnote
Phylloquinone is commonly referred to as Vitamin K1.
428
True or False: Vitamin K2 is also known as phylloquinone.
False
## Footnote
Vitamin K2 refers to menaquinone, not phylloquinone.
429
What are the two main types of Vitamin K?
Phylloquinone and Menaquinone
## Footnote
These are the natural forms of Vitamin K, with phylloquinone from plants and menaquinone from bacteria.
430
List the synthetic forms of Vitamin K.
* Menadione
* Menadiol
## Footnote
These synthetic forms are used in various applications, including dietary supplements.
431
What is the primary form of Vitamin K synthesized by plants?
Phylloquinone
## Footnote
Phylloquinone is the natural form of Vitamin K found in green leafy vegetables.
432
Which form of Vitamin K is synthesized by colonic bacteria?
Menaquinone
## Footnote
Menaquinone refers to a group of compounds with varying lengths of side chains, primarily produced by bacteria in the human gut.
433
What is the synthetic form of Vitamin K known as?
Menadione
## Footnote
Menadione is a man-made version of Vitamin K that is used in dietary supplements.
434
What is the synthetic form of Vitamin K4?
Menadiol
## Footnote
Menadiol is another synthetic derivative of Vitamin K, often used in supplements.
435
Fill in the blank: Vitamin K1 is also known as _______.
Phylloquinone
## Footnote
Phylloquinone is commonly referred to as Vitamin K1.
436
True or False: Vitamin K2 is also known as phylloquinone.
False
## Footnote
Vitamin K2 refers to menaquinone, not phylloquinone.
437
What are the two main types of Vitamin K?
Phylloquinone and Menaquinone
## Footnote
These are the natural forms of Vitamin K, with phylloquinone from plants and menaquinone from bacteria.
438
List the synthetic forms of Vitamin K.
* Menadione
* Menadiol
## Footnote
These synthetic forms are used in various applications, including dietary supplements.
439
What is the role of Vitamin K in bone health?
Required as a co-factor for synthesis of osteocalcin and bone matrix GLA protein
## Footnote
Vitamin K is essential for the proper functioning of osteocalcin, which is crucial for bone mineralization and maturation.
440
What is osteocalcin?
An abundant bone protein that is required for bone mineralization and maturation
## Footnote
Osteocalcin plays a critical role in the structure and strength of bones.
441
How does Vitamin K affect osteocalcin?
Helps in the carboxylation of osteocalcin, enhancing its calcium-binding properties
## Footnote
The carboxylation process is vital for osteocalcin to effectively bind calcium, which is necessary for bone strength.
442
Fill in the blank: Vitamin K is required as a co-factor for the synthesis of _______.
osteocalcin
443
True or False: Osteocalcin is not important for bone health.
False
## Footnote
Osteocalcin is crucial for bone mineralization and maturation, highlighting its importance in bone health.
444
What is the dietary requirement for Vitamin K in adults?
1 µg/kg/day
## Footnote
This amount is considered safe and adequate.
445
What is the primary reason babies are given prophylactic vitamin K at birth?
To protect against haemorrhagic disease
## Footnote
Haemorrhagic disease is a rare but life-threatening condition caused by vitamin K deficiency in early life.
446
Is there sufficient data available to establish accurate Dietary Reference Values (DRVs) for Vitamin K?
No
## Footnote
There is limited data on requirements and vitamin K content of foods.
447
True or False: Adults have a well-defined DRV for Vitamin K.
False
## Footnote
Too little information exists to establish accurate DRVs.
448
Fill in the blank: All babies are given prophylactic vitamin K at birth to protect against _______.
haemorrhagic disease
449
What are the primary sources of Vitamin K1?
Green leafy vegetables (broccoli, cabbage, spinach), margarines, vegetable oils
## Footnote
Vitamin K1 is primarily found in plant-based foods.
450
What are the sources of Vitamin K2?
Moderate amounts in animal liver, small amounts in egg yolks, butter, cheese, large amounts in tofu
## Footnote
Vitamin K2 is more prevalent in animal products and fermented foods.
451
What is the unique source of Vitamin K3?
Produced by colonic bacteria
## Footnote
Vitamin K3 is a less commonly discussed form of Vitamin K, synthesized in the gut.
452
How is Vitamin K absorbed in the body?
Vitamin K is absorbed along with fat in the small intestine.
453
What is the absorption percentage of Vitamin K in healthy adults?
Approximately 80%.
454
In what form is Vitamin K transported to the liver?
In chylomicrons.
455
Where is Vitamin K predominantly stored in the body?
In the liver.
456
Besides the liver, where else is Vitamin K thought to be stored?
In adipose tissue.
457
How is Vitamin K absorbed in the body?
Vitamin K is absorbed along with fat in the small intestine.
458
What is the absorption percentage of Vitamin K in healthy adults?
Approximately 80%.
459
In what form is Vitamin K transported to the liver?
In chylomicrons.
460
Where is Vitamin K predominantly stored in the body?
In the liver.
461
Besides the liver, where else is Vitamin K thought to be stored?
In adipose tissue.
462
What increases the risk of haemorrhage?
Vitamin K deficiency
## Footnote
Vitamin K is crucial for blood clotting; its deficiency can lead to increased bleeding risk.
463
What factors contribute to vitamin K deficiency in infancy?
* Sterile intestinal tract
* Limited amount in human and cow's milk
* Malabsorption syndromes
* Prolonged use of antibiotics
* Megadoses of vitamin A and E
* Anticoagulant therapy
## Footnote
These factors can hinder vitamin K absorption or utilization.
464
Is vitamin K deficiency common in healthy adults?
No, deficiency is rare in healthy adults.
## Footnote
Healthy adults typically have sufficient vitamin K levels.
465
What preventive measure is taken for infants regarding vitamin K?
Infants receive a vitamin K injection at birth.
## Footnote
This is to prevent bleeding disorders due to deficiency.
466
What are some malabsorption syndromes related to vitamin K deficiency?
* Celiac disease
* Cystic fibrosis
* Ulcerative colitis
* Crohn's disease
## Footnote
These conditions affect the absorption of nutrients, including vitamin K.
467
How does prolonged use of antibiotics affect vitamin K levels?
It kills gut bacteria that produce vitamin K.
## Footnote
Antibiotics disrupt the microbiome, which can lead to deficiencies.
468
What is the effect of megadoses of vitamin A on vitamin K?
They counteract the actions of vitamin K.
## Footnote
High levels of vitamin A can inhibit vitamin K's effectiveness.
469
How does vitamin E affect vitamin K-dependent clotting factors?
It decreases vitamin K-dependent clotting factors, thus promoting bleeding.
## Footnote
Vitamin E can interfere with the clotting process.
470
What is the importance of consistent vitamin K intake for individuals on anticoagulant therapy?
Large fluctuations can interfere with the effectiveness of anticoagulant drugs like Warfarin (Coumadin).
## Footnote
Maintaining stable vitamin K levels is crucial for managing blood clotting risks.
471
What is the evidence of toxicity for Vitamin K when taken in natural oral form?
Little evidence of toxic effects, even in mg quantities.
## Footnote
Natural forms of Vitamin K are generally considered safe.
472
How is Vitamin K secreted from the body?
Rapidly secreted.
## Footnote
This rapid secretion may contribute to its low toxicity.
473
What should be avoided in newborns regarding Vitamin K?
Synthetic preparations of menadione.
## Footnote
Menadione has been linked to cases of haemolysis and liver damage in newborns.
474
Which form of Vitamin K is recommended for newborns?
Phylloquinone derived from plant sources.
## Footnote
Phylloquinone is the natural form of Vitamin K found in green leafy vegetables.
