Vitamins Flashcards
(181 cards)
1
Q
What are vitamins?
A
Organic compounds required in small amounts for normal body functioning and metabolic integrity.
Essential for life and well-being.
2
Q
What are the two main classifications of vitamins?
A
Water-soluble and fat-soluble.
3
Q
How are water-soluble vitamins absorbed?
A
Directly to blood.
4
Q
How are fat-soluble vitamins transported in the body?
A
Via lymph through chylomicrons.
5
Q
What is the storage method for water-soluble vitamins?
A
Not stored (except B12), circulate freely.
6
Q
What is a key characteristic of vitamins?
A
Easily destroyed by cooking and processing.
7
Q
Fill in the blank: Deficiencies can be _______.
A
fatal.
8
Q
What is the excretion method for water-soluble vitamins?
A
Unchanged via urine.
9
Q
What are some preferred cooking methods for retaining water-soluble vitamins?
A
- Steaming
- Stir-fry
- Microwave
10
Q
What are enzyme cofactors?
A
Non-protein molecules (e.g., vitamins) required for enzyme activity.
11
Q
What is the typical intake of thiamine (B1) in the UK?
A
2.0-2.3 mg/d.
12
Q
What is the primary function of thiamine (B1)?
A
Coenzyme necessary for metabolism of carbohydrates, fats, and proteins.
13
Q
What condition is associated with thiamine deficiency?
A
Beriberi.
14
Q
True or False: Riboflavin (B2) is a significant public health problem.
A
False.
15
Q
What is the primary source of niacin?
A
Protein sources (beef, pork, chicken).
16
Q
What disease is caused by niacin deficiency?
A
Pellagra.
17
Q
What is the typical intake of pyridoxine (B6) in the UK?
A
2.9-3.3 mg/d.
18
Q
Fill in the blank: Folic acid (B9) is involved in converting homocysteine to _______.
A
methionine.
19
Q
What is the primary function of cobalamin (B12)?
A
Co-enzyme in the transfer of 1C groups.
20
Q
What is the consequence of cobalamin (B12) deficiency?
A
Pernicious anemia.
21
Q
What is the typical intake of pantothenic acid (B5) in the UK?
A
No RNI established.
22
Q
What are some food sources of biotin?
A
- Liver
- Eggs
- Dairy products
23
Q
What condition can arise from biotin deficiency?
A
Scaly dermatitis.
24
Q
What is the typical intake of vitamin C (ascorbic acid) in the UK?
A
Not specified in the provided text.
25
What is the main metabolic function of riboflavin (B2)?
Metabolizes carbohydrates, fats, and proteins into glucose.
26
Fill in the blank: Vitamin B6 is involved in the synthesis of _______.
neurotransmitters.
27
What is the role of folic acid in DNA synthesis?
Involved in purine synthesis.
28
What is the primary source of vitamin B12?
Animal products (meat, eggs, dairy).
29
What can excessive intake of niacin lead to?
Liver damage.
30
True or False: Toxicity is possible with water-soluble vitamins.
True.
31
What is acetyl-CoA involved in?
Carboxylation and elongation of PUFA hydrocarbon chain
## Footnote
Acetyl-CoA is a central metabolite in various biochemical pathways.
32
What is biotin deficiency commonly associated with?
Long-term total parenteral nutrition, consumption of >12 raw eggs/day
## Footnote
Avidin in raw egg whites binds biotin, leading to deficiency.
33
What are common symptoms of biotin deficiency?
* Scaly dermatitis
* Glossitis
* Alopecia (hair loss)
## Footnote
No RNI established for biotin.
34
Why can't humans synthesize vitamin C?
Lack the enzyme gulonolactone oxidase
## Footnote
This enzyme is a result of mutations in the gene coding for it.
35
What is the typical intake of vitamin C in the UK?
30-90 mg/d
## Footnote
Vitamin C is highly absorbed (80-95%) from food.
36
What are the metabolic functions of vitamin C?
* Co-enzyme in collagen synthesis
* Hydroxylation of dopamine
* Synthesis of carnitine
* Enhances absorption of iron
## Footnote
Vitamin C also acts as an antioxidant.
37
What is scurvy?
Vitamin C deficiency disease
## Footnote
Symptoms include bleeding gums, weakness, and hyperkeratosis.
38
What are symptoms of vitamin C toxicity?
* Diarrhea
* Kidney oxalate stone formation
## Footnote
High doses of vitamin C (1-10 g/d) may lead to these issues.
39
What is carnitine's role in the body?
Transport of long-chain fatty acids into mitochondria for β-oxidation
## Footnote
Carnitine is synthesized in the body.
40
How are fat-soluble vitamins characterized?
Found in fat/oily parts of food, require fat absorption, stored in body lipid fractions
## Footnote
Excess accumulation can be harmful.
41
What are the four fat-soluble vitamins?
* Vitamin A
* Vitamin D
* Vitamin E
* Vitamin K
## Footnote
These vitamins are absorbed differently than water-soluble vitamins.
42
What are the sources of pre-formed vitamin A?
* Retinol
* Retinal
* Retinoic acid
* Retinyl esters
Main sources include animal products like liver and fish.
43
What are the symptoms of vitamin A deficiency?
* Night blindness
* Xerophthalmia
* Increased susceptibility to infections
## Footnote
Vitamin A deficiency is a major public health issue in some regions.
44
What is the acute toxicity level for retinol in adults?
>200 mg
## Footnote
Symptoms include vomiting, blurred vision, and irritability.
45
What is the primary source of vitamin D from food?
* Cholecalciferol (D3) - animal sources
* Ergocalciferol (D2) - plant sources
## Footnote
Vitamin D can also be synthesized in the skin with sunlight.
46
What are the metabolic functions of vitamin D?
* Plasma calcium homeostasis
* Enhances calcium absorption
* Mobilizes bone mineral
## Footnote
Vitamin D is crucial for bone health.
47
What are the signs of vitamin D deficiency in children?
* Rickets
* Poor mineralization of bones
## Footnote
Rickets is characterized by delayed growth and irregular growth plates.
48
What food sources are high in vitamin E?
* Wheatgerm oil
* Almonds
* Sunflower seeds
* Hazelnuts
## Footnote
Vitamin E is primarily found in plant oils.
49
What are the metabolic functions of vitamin E?
* Anti-oxidant
* Maintains cell membrane integrity
## Footnote
Vitamin E protects cells from oxidative damage.
50
What are the two bioactive forms of vitamin K?
* Vitamin K1 (phylloquinones)
* Vitamin K2 (menaquinones)
## Footnote
Vitamin K is essential for blood clotting and bone metabolism.
51
What are the consequences of vitamin K deficiency?
* Poor blood clotting
* Haemorrhagic disease
## Footnote
Newborns are often given vitamin K injections to prevent deficiency.
52
What is the recommended intake for vitamin K in the UK?
0.5–1.0 µg/kg/day
## Footnote
Difficult to induce deficiency through diet alone.
53
What are vitamins
Organic compounds that are required in small amounts for normal functioning and maintenance of metabolic integrity
54
Can vitamins be synthesised in the body
No
55
How are water soluble vitamins and fat soluble vitamins absorbed
Water- directly to blood
Fat- lymph via chylomicrons
56
Which type of vitamins require a transport carrier
Fat soluble
57
How are fat soluble vitamins stored
In cells (adipose, liver) with fat
58
Are water soluble vitamins stored
No except for, B12, they circulate freely
59
How are water soluble vitamins excreted
In urine
60
What are the requirements for water soluble vitamins
2-3 days
61
What are the requirements for fat soluble vitamins
Every week
62
Where are water soluble vitamins absorbed into
Hepatic portal vein
63
What are vitamers
Chemically related compounds with the same biological activity
64
What are enzyme co factors
An additional other non-protein molecule e.g. vitamins that aids enzyme function
65
What is an enzyme without a cofactor
Apoenzymes
66
What is an enzyme with a cofactor
Holoenzyme
67
What is vitamin B1
Thiamine
68
What are the sources of B1/thiamine
Pork, meat, fish, potatoes, whole grain cereals, yeast, pulse, nuts, flour and fortified breads
69
What are the functions of thiamine
Food metabolism
Coenzyme in macronutrient metabolism
Cellular respiration and fatty acid oxidation
Energy production in mitochondria and protein synthesis
Nervous function and neurotransmitter synthesis
70
What are the two types of thiamine deficiency
Wet and dry
71
What are wet thiamine deficiencies
Cardiac effects
72
What are dry thiamine deficiencies
Neurological effects
73
What are specific outcomes of thiamine deficiency
Beriberi, wernicke-korsakoff syndrome
74
How much thiamine could be toxic
>3g/day
75
What are symptoms of thiamine toxicity
Headache, insomnia, weakness, tachycardia, pruritis, allergic reaction
76
What are sources of riboflavin/B2
Milk/dairy, eggs, liver and kidney, yeast, fortified cereals and fish
77
What is the function of riboflavin/B2
Metabolism of CHO, fats and protein in glucose, coenzyme in metabolic pathways (FAD), metabolises drugs, iron and vitB6, needed for niacin synthesis, antioxidant, RBC synthesis
78
What are the effects of riboflavin deficiency
Ariboflavinosis, dermatitis, low metabolic rate, cheilosis, stomatitis, desquamation of tongue, vascularisation of cornea, malaria resistance, pooor growth neonates
79
What are the 2 forms of niacin
Nicotinic acid and nicotinamide
80
What amino acid can niacin be synthesised from
Tryptophan
81
What are the sources of niacin
Beef, pork, chicken, eggs, milk, coffee beans, soaked maize
82
What are the functions of niacin
Functional part of NAD, protein metabolism, coenzyme in carbohydrate, protein, fat and alcohol metabolism, DNA repair, calcium mobilisation, fatty acid and steroid synthesis, precursor to coenzyme NAD, involved in antioxidant systems
83
What are the effects of niacin deficiency
Pellagra (dermatitis, diarrhoea, dementia, death)
84
How much niacin is considered toxic
>500mg/d (liver), >1-6g/d
85
What are the several forms of B6
Pyridoxine, pyridoxal, pyridoxamine and phosphorylated form of all three
86
What are the sources of B6
Meat, whole grain and fortified cereals, banana, nuts, pulses
87
What are the functions of B6
Food metabolism, cofactor for glycogenolysis, transanimation and decarboxylation of AA, neurotransmitter synthesis, heme synthesis, steroid hormone regulation
88
What are the effects of B6 deficiency
Disorders of AA metabolism and hormone dependent cancers
89
How much B6 is considered toxic
2-7g/d- sensory neuropathy and 200mg/d for peripheral neuropath6 and muscle weakness
90
What are the two forms of folic acid/B9
Folic acid and folate
91
What are sources of folic acid
Brussel sprouts, kale, spinach, pulses and enriched flour
92
What are the functions of B9/folic acid
Conenzyme in C1 group transfer, conversion of homocysteine to methionine, purine synthesis, DNA and RNA synthesis
93
What are the effects of folic acid deficiency
Megloblastic anaemia(abnormally large RBC), neural tube defects, hyperhomocysteinemia (thrombosis, hypertension)
94
How much folic acid is considered toxic
>400 micrograms a day
95
What are sources of colalamin/B12
Meat, eggs, milk, dairy, fish, yeast
96
What are the metabolic functions of cobalamin
Coenzyme in c1 transfer, folic acid metabolism, myelination of nerves
97
How are cobalamin and folic acid conserved in the body
Enterohepatic circulation
98
What are the effects of cobalamin/B12 deficiency
Impaired digestion and absorption, pernicious anaemia, increased methylmalonic acid excretion
99
What are sources of pantothenic acid/B5
Yeast, offal, meat, green veg, peanuts
100
What are the functions of B5/pantothenic acid
Functional part of coenzyme A, dietary CHO,fat and protein metabolism, carrier of acetyl groups, cholesterol, steroid hormone, LCFA, Ach, heme, melatonin and vit A and D synthesis, fatty acid carrier
101
What are the effects of pantothenic acid deficiency
Peripheral nerve damage (burning foot syndrome)
102
What are the forms of Biotin/ vitamin H
Biotin, biocytin, carboxy-biocytin
103
What are the sources of biotin
Liver, kidney, milk/dairy, eggs
104
Where is biotin synthesised
Intestinal microflora
105
What are the functions of biotin/H
Coenzyme in gluconeogenesis and fatty acid synthesis, coenzyme in metabolism of branched chain AA
106
What are the effects of biotin deficiency
Dermatitis, glossitis, alopecia, impaired fat and CHO metabolism
107
What are the 3 forms of vitamin C
Ascorbate, ascorbic acid, dehydroascorbste
108
Why can’t humans synthesis vitamin C
Lack enzyme gulonolactone oxidase due to mutation in gene that codes for enzyme
109
What are sources of vitamin C
Fruits and vegetables
110
What are the functions of vitamin C
Coenzyme in hydroxylation of proline and lysine residues in collagen synthesis, dopamine hydroxylation, carnitine synthesis, bile synthesis, protein c modification, antioxidant, high protein-oxidant conc, iron absorption enhancer
111
What are the effects of vit C deficiency
Scurvy (impaired wound healing, bleeding gums, fatigue, hyper keratosis, subcutaneous haemorrhage, loss of dental cement) and anaemia
112
How much vitamin C can prevent scurvy symptoms
10mg/d
113
What are the symptoms of vitamin C toxicity
Diarrhoea, kidney oxalate stone formation
114
What are considered toxic does of vitamin C
1-10g/d
115
What is the function of carnitine
LCFA transport
116
What is the function of choline and inositol
Component of membrane phospholipids
117
What is the function of taurine
Bile salts
118
What is the function of ubiquinone
Electron carrier and antioxidant
119
What are the 4 fat soluble vitamins
A,D,E and K
120
What are the preforms of vitamin A
Retinol, retinal, retinoic acid, retinyl esters, carotene and carotenoid compounds, pro vitamin A
121
Which form of vitamin A is the storage form
Retinyl esters
122
Which form of vitamin A is cleaved to form retinal
Pro-vitamin A
123
What are the sources of vitamin A
Vegetables, meat and liver, fats, milk
124
What is the function of retinal
Rhodopsin production, vision in dim light
125
What is the function of retinoic acid
Growth, cell differentiation, immune responses , embryogenesis, interact with DNA (nuclear acting)
126
What is the function of beta carotene
Antioxidant
127
What are the effects of vitamin A deficiency
Night blindness, xerophthalmia, skin keratinisation, increased susceptibility to inefectiohs disease, link to anaemia
128
What are the effects of vitamin A toxicity
Vomiting, abdominal pain, anorexia, blurred vision, headche, muscle and bone pain, skin disorders, alopecia, ataxia, liver toxicity, hyperlipidemia
129
What is considered acute vitamin A toxicity
>200mg
130
What is considered chronic vitamin A toxicity
>10mg/month
131
What is the upper limit intake of vitamin A in pregnancy
>3mg/day
132
What are the two bioactive forms of vitamin K
Vitamin K1 and K2
133
What are the sources of vitamin K
Phylloquinones, menaquinones, green leafy veg, vegetable oils, eggs, meat, dairy
134
What are the functions of vitamin K
Coenzyme in protein synthesis for proteins in blooding clotting and bone metabolism, synthesis of y-carboxyglutamic acid in liver (essential for enzymes in blood coagulation), bone matrix (osteocalcin)
135
What are the effects of vitamin K deficiency
Poor blood clotting/low prothrombin activity, haemorrhagic disease, obstructive jaundice, blocked vitamin K recycling in liver
136
What are the effects of vitamin K toxicity
Liver overload and brain toxicity
137
Which vitamins do not have an RNI
Vitamin K, biotin/vitamin H, vitamin E, pantothenic acid
138
What is the safe intake of vitamin K
0.5-1 micrograms/kg/d
139
What are the forms of vitamin E
Tocopherols, tocotrienols
140
What are the sources of vitamin E
Wheat germ oil, almonds, sunflower seeds and oil, safflower oil, hazelnuts, peanuts and peanut butter, cod oil
141
What are the functions of vitamin E
Antioxidant, cell membrane maintenance and protection, regulated prostaglandin synthesis, DNA synthesis
142
What are the effects of vitamin E deficiency
Neurological dysfunction, reduced tendon reflexes, loss of touch and pain sensations, impaired coordination, unsteady gait,
143
What are the effects of vitamin E toxicity
Antagonistic to vitamin A,D and K, headaches, nausea, muscle weakness, double vision, creatinuria, gastrointestinal disturbances
144
How much vitamin E is considered toxic
>900mg/kg
145
What are the two forms of vitamin D
Cholecalciferol (D3) - animal
Ergocalciferol (D2)- plant
146
What can vitamin D be synthesised from in skin
7-dehydrocholestrol (and UVB sunlight)
147
What are the functions of vitamin D
Calcium homeostasis, mobilisation of bone minerals, teeth and bone mineralisation, inhibits cell proliferation in some cancers
148
What are the effects of vitamin D deficiency
Rickets (irregular growth plates), osteomalacia, impaired immune function
149
What 5 factors are associated with rickets
High latitude, lack of sunlight exposure (overcrowding, social customs, clothing, pollution), imfants with mothers who were vit D deficient during pregnancy, low dietary calcium intake, increased melanin pigmentation
150
What are the effects of vitamin D toxicity
hypercalciemia, thirst, anorexia, soft tissue calcification, urinary calcium stones
151
What are the effects of vitamin D toxicity
hypercalciemia, thirst, anorexia, soft tissue calcification, urinary calcium stones
152
Which vitamins do NOT have a defined recommended nutrient intake (RNI)?
Vitamin K, vitamin E, Biotin, pantothenic acid
153
Which B vitamin can be synthesised from AA tryptophan
Niacin
154
Which vitamins have an additional requirement during pregnancy
Thiamine, riboflavin, folic acid, vitamin C and A
155
Which vitamin is pro oxidant at high concentrations
Vitamin C
156
What two vitamin deficiency can result in megaloblastic anaemia
Folic acid and cobalamin
157
Which B vitamins requires parietal cells in the stomach to secrete intrinsic factor to aid its absorption in the small intestine?
Cobalamin
158
Which vitamins does NOT have an additional requirement during lactation?
B6
159
Which TWO of the fat-soluble vitamins does NOT have a defined recommended nutrient intake (RNI)?
K and E
160
Which of the forms of vitamin A enables vision in dim light?
Retinal
161
Which vitamins act as anti-oxidants?
Vitamin C, riboflavin/B2, vitamin E
162
Which form of vitamin A interacts with DNA to regulate gene transcription?
Retinoic acid
163
Which vitamin is required for effective blood clotting
Vitamin K
164
Which vitamin deficiency is linked to veganism
Cobalamin
165
Name TWO environmental factors that can affect the skin biosynthesis of vitamin D
Pollution, latitude
166
Name social factors that can affect the skin biosynthesis of vitamin D
Clothing, overcrowding, social cultural religious customs
167
Megaloblastic anaemia can be caused by a deficiency in either
Folate, cobalamin
168
Name micronutrients white flour is fortified with
Folic acid, thiamine, niacin
169
Wernicke-Korsakoff syndrome is associated with excessive alcohol consumption. Alcohol inhibits the absorption of which B vitamins?
Thiamine
170
Which B vitamins can be stored in the body?
Cobalamin
171
Which B vitamins can be stored in the body?
Cobalamin
172
What are bibots spots, keratomalacia and xerophthalamia associated with
Vitamin A deficiency
173
What are osteomalacia and rickets associated with
Vitamin D deficiency
174
What is haemorrhaging disease associated with
Vitamin K deficiency
175
What is pellagra associated with
Niacin deficiency
176
What is neural tube defects associated with
Folic acid deficiency
177
What is cheilosis associated with
Riboflavin deficiency
178
What is consumption of maize associated with
Pellagra/ niacin deficiency
179
What is burning foot syndrome associated with
Pantothenic acid deficiency/ severe malnutrition
180
What is long term parenteral nutrition associated with
Glossitis/ biotin deficiency
181
Name biological factors that can increase the risk of developing rickets.
Deficiency during pregnancy, prolonged breastfeeding, increased melanin pigment, lack of sunlight, low dietary calcium
