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Water Soluble Vitamins Flashcards

1
Q

What are the characteristics of fat-soluble vitamins?

A

Soluble in fat, not soluble in water, not excreted in urine, stored in the body, can be toxic, less easily destroyed by heat

Examples include Vitamins A, D, E, and K.

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2
Q

What are the characteristics of water-soluble vitamins?

A

Soluble in water, excreted in urine, very small amounts stored in the body, required daily, some are easily destroyed by sunlight and heat

Examples include Vitamin C and the B vitamins.

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3
Q

Fill in the blank: Fat-soluble vitamins are _______ in fat.

A

soluble

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4
Q

True or False: Water-soluble vitamins can be toxic when stored in the body.

A

False

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5
Q

Fill in the blank: Water-soluble vitamins are _______ in urine.

A

excreted

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6
Q

Which type of vitamins are required daily due to their storage capacity in the body?

A

Water-soluble vitamins

Fat-soluble vitamins can be stored for longer periods.

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7
Q

Fill in the blank: Fat-soluble vitamins are less easily destroyed by _______.

A

heat

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8
Q

What happens to water-soluble vitamins when exposed to sunlight?

A

Some are easily destroyed

This can affect their availability and nutritional value.

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9
Q

What are the B vitamins?

A

B1 (thiamin), B2 (riboflavin), B3 (niacin, nicotinic acid, nicotinamide), B5 (pantothenic acid), B6 (pyridoxine), B12 (cobalamin), Folate, Biotin

B vitamins are essential for energy production and other metabolic processes.

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10
Q

What is the chemical name for Vitamin C?

A

Ascorbic Acid

Vitamin C is important for the growth and repair of tissues in the body.

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11
Q

Fill in the blank: B1 is also known as _______.

A

thiamin

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12
Q

Fill in the blank: B2 is also known as _______.

A

riboflavin

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13
Q

Fill in the blank: B3 is also known as _______.

A

niacin, nicotinic acid, nicotinamide

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14
Q

Fill in the blank: B5 is also known as _______.

A

pantothenic acid

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15
Q

Fill in the blank: B6 is also known as _______.

A

pyridoxine

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16
Q

Fill in the blank: B12 is also known as _______.

A

cobalamin

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17
Q

Fill in the blank: Folate is also known as _______.

A

folic acid

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18
Q

Fill in the blank: Biotin is also known as _______.

A

Vitamin H

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19
Q

What are water-soluble vitamins?

A

Vitamins that are hydrophilic and leak out of vegetables into water during cooking

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20
Q

What cooking methods are better for preserving water-soluble vitamins?

A

Steaming, stir-frying, and microwaving

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21
Q

What happens to B vitamins during grain processing?

A

Most B vitamins are removed, resulting in refined grains

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22
Q

What is enrichment in the context of food?

A

The addition of micronutrients to a food which are lost during processing

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23
Q

Define fortification in food processing.

A

Deliberately increasing the content of an essential micronutrient in food to improve nutritional quality

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24
Q

True or False: Fortification only applies to nutrients that were originally present in the food.

A

False

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25
What is the purpose of fortification?
To provide a public health benefit with minimal risk to health
26
Fill in the blank: Processing grains removes most _____ vitamins.
B
27
What is the difference between enrichment and fortification?
Enrichment refers to adding lost micronutrients, while fortification increases micronutrient content regardless of original presence
28
What is B12?
A vitamin only found in animal sources
29
What are the functions of B vitamins?
Coenzymes in metabolism and facilitate the use of energy in the body ## Footnote B vitamins are involved in the transformation to other metabolites, such as in the Krebs/citric acid cycle.
30
Which B vitamins are involved in cell division?
Folate and B12 ## Footnote These vitamins play a crucial role in the process of cell division.
31
True or False: Some B vitamins work independently of each other.
False ## Footnote Certain B vitamins, such as riboflavin and niacin, as well as folate and B12, work together.
32
Fill in the blank: B vitamins are essential for _______.
energy metabolism ## Footnote Energy metabolism refers to the biochemical processes that convert nutrients into energy.
33
What role do B vitamins play in the Krebs/citric acid cycle?
They are involved in the transformation to other metabolites ## Footnote This cycle is a key part of cellular respiration, allowing for energy production.
34
What is the first step of glycolysis?
Glucose is converted to pyruvate ## Footnote Glycolysis is the metabolic pathway that converts glucose into pyruvate.
35
What happens to pyruvate in the presence of oxygen?
Pyruvate is converted into acetyl CoA in mitochondria ## Footnote Acetyl CoA is a key molecule that enters the Krebs cycle.
36
What happens to pyruvate in the absence of oxygen?
Pyruvate is converted into lactate in the cytosol ## Footnote This process is known as anaerobic fermentation.
37
What cycle does acetyl CoA enter after its formation?
Krebs cycle ## Footnote The Krebs cycle is also known as the citric acid cycle.
38
What is produced at each stage of glycolysis, the Krebs cycle, and ETC?
ATP and NADH ## Footnote ATP is the energy currency of the cell, while NADH is an electron carrier.
39
What is the chemical name for Vitamin B1?
Thiamin ## Footnote Thiamin is also known as thiamine.
40
What are the two forms of Thiamin mentioned?
Thiamin diphosphonate, Thiamin pyrophosphate ## Footnote These are the active forms of Thiamin in the body.
41
What does 'Thio' refer to in the term Thiamin?
Sulfur ## Footnote 'Thio' indicates the presence of sulfur in the chemical structure.
42
What does 'Amine' refer to in the term Thiamin?
Nitrogen containing group ## Footnote 'Amine' signifies that the compound contains a nitrogen atom.
43
Is Thiamin stable in light and heat?
No ## Footnote Thiamin is unstable when exposed to light and heat.
44
What is the primary function of Thiamin in the body?
Metabolism of carbohydrates ## Footnote Thiamin helps the body convert carbohydrates into energy.
45
Thiamin is essential for the functioning of which types of cells?
Heart and nerve cells ## Footnote Thiamin plays a critical role in maintaining the health of these cells.
46
Fill in the blank: The active form of Thiamin is _______.
TPP ## Footnote TPP stands for Thiamin Pyrophosphate, the coenzyme form of Thiamin.
47
What is the coenzyme for several multi-enzyme complexes?
Thiamin diphosphate/pyrophosphate
48
Which metabolic functions involve decarboxylation reactions?
* Pyruvate dehydrogenase * Alpha-keto-glutarate dehydrogenase * Branched-chain keto-acid dehydrogenase * Transketolase
49
What does decarboxylation refer to?
A chemical reaction that removes a carboxyl group and releases carbon dioxide (CO₂)
50
What is the role of TPP in metabolism?
Catalyses oxidative decarboxylation
51
What does PDH convert pyruvate to?
Acetyl-CoA
52
What is the rate limiting step of leucine, isoleucine, and valine catabolism?
Oxidative decarboxylation of branched-chain a-keto acids (BCKAs)
53
What does the pentose phosphate pathway generate?
* NADPH * Pentoses (5-carbon sugars) * Ribose 5-phosphate
54
Is the pentose phosphate pathway primarily anabolic or catabolic?
Anabolic
55
Which cells are especially dependent on the pentose phosphate pathway?
Red blood cells (erythrocytes)
56
Fill in the blank: PDH converts pyruvate to _______.
Acetyl-CoA
57
True or False: The pentose phosphate pathway involves the oxidation of glucose.
True
58
What is the function of thiamin in the body?
Thiamin assists in the conversion of pyruvate to acetyl CoA
59
What is thiamin pyrophosphate (TPP)?
Thiamin pyrophosphate is the active form of thiamin that acts as a coenzyme
60
What does TPP remove during its function?
TPP removes a carboxyl group
61
What is released when TPP removes a carboxyl group?
CO2 is released
62
What are the main components involved in the conversion of pyruvate to acetyl CoA?
Pyruvate, thiamin pyrophosphate, NADH, NAD+, and Coenzyme A
63
True or False: Thiamin is the vitamin portion of the coenzyme TPP.
True
64
Fill in the blank: Thiamin is essential for the enzyme __________.
pyruvate dehydrogenase
65
What is the primary form in which thiamin (Vitamin B1) is present in foods?
Diphosphate (thiamin pyrophosphate) ## Footnote Small amounts of mono- and triphosphate also occur.
66
What effect does sulphite treatment have on thiamin?
Results in great/complete loss of thiamin ## Footnote Thiamin is easily altered by sulphite.
67
What are some food sources of thiamin?
* Whole-grain products * Enriched grains (e.g., white flour fortified with thiamin 2.4mg/kg) * Fortified breakfast cereals * Legumes * Nuts & seeds * Fish and seafood * Pork * Potatoes ## Footnote Thiamin is a water-soluble vitamin important for energy metabolism.
68
What vitamin is referred to as B1?
Thiamin ## Footnote Thiamin is also known as vitamin B1.
69
How quickly can signs of thiamin deficiency be observed?
Within 10 days ## Footnote This is due to the little storage of thiamin in the body.
70
What happens when there is a large carbohydrate intake without thiamin?
Impaired conversion of pyruvate to acetyl CoA ## Footnote This impairment prevents pyruvate from entering the citric acid cycle to produce energy.
71
What is the recommended thiamin intake for adults consuming ~2000 kcal/day?
1.6-1.8 mg/day ## Footnote This intake is suggested for adults during pregnancy and lactation.
72
True or False: The body has significant storage of thiamin.
False ## Footnote The body has little storage of thiamin, leading to quick deficiency signs.
73
Fill in the blank: Signs of thiamin deficiency can be observed within _______.
10 days ## Footnote This rapid onset is due to minimal storage of thiamin in the body.
74
What is thiamin also known as?
Vitamin B1 ## Footnote Thiamin is essential for carbohydrate metabolism and neural function.
75
What are the syndromes associated with thiamin deficiency?
* Beriberi (acute and chronic) * Wernicke's encephalopathy * Korsakoff's psychosis ## Footnote These conditions can arise from prolonged thiamin deficiency, affecting the nervous system.
76
Which systems in the body rely on glucose for energy?
Brain and CNS ## Footnote The central nervous system is particularly sensitive to glucose availability.
77
What dietary pattern is associated with thiamin deficiency?
High in carbohydrates and low in thiamin ## Footnote Such diets can lead to insufficient thiamin intake, resulting in deficiency syndromes.
78
What are the first signs of thiamin deficiency?
* Weakness * Fatigue * Headache * Depression ## Footnote These symptoms may indicate the onset of more severe deficiency-related conditions.
79
What are the symptoms of wet or acute beri-beri?
Oedema affects leg, ankles, face, trunk, lungs and peritoneal cavity; Enlarged heart and heart failure; High pyruvate and lactate in plasma ## Footnote Wet beri-beri is associated with high carbohydrate intake.
80
What are the symptoms of dry or chronic beri-beri?
Low food intake; Nerve degeneration; Muscles wasted and weak; Fatigue; Poor coordination; Lack of sensation in feet; Deep muscle pain ## Footnote Dry beri-beri occurs in individuals with inadequate food intake.
81
What is the main nutritional deficiency associated with beri-beri?
Thiamin deficiency ## Footnote Thiamin is also known as vitamin B1.
82
Fill in the blank: High carbohydrate intake is associated with _______ beri-beri.
wet ## Footnote Wet beri-beri presents with edema and cardiovascular issues.
83
True or False: Peripheral nerves are affected in dry beri-beri leading to a lack of sensation in the feet.
True ## Footnote This symptom indicates nerve degeneration due to thiamin deficiency.
84
What are the characteristic symptoms of nerve degeneration in dry beri-beri?
Muscles wasted and weak; Fatigue; Poor coordination; Lack of sensation in feet; Deep muscle pain ## Footnote These symptoms highlight the impact of thiamin deficiency on the nervous system.
85
What vitamin deficiency can be seen in heavy alcohol consumption in industrialised countries?
B1 deficiency ## Footnote B1 is also known as thiamine, which is essential for energy metabolism.
86
What is Wernicke-Korsakoff Syndrome typically caused by?
Excess alcohol intake ## Footnote Typically seen in ageing alcoholics
87
What vitamin is needed for the metabolism of alcohol?
Thiamin
88
What are the initial symptoms of Wernicke-Korsakoff Syndrome?
Confusion and staggering ## Footnote Symptoms related to Korsakoff's psychosis
89
What are the later symptoms of Wernicke-Korsakoff Syndrome?
Wernicke's encephalopathy ## Footnote Characterized by CNS lesions
90
What is a specific symptom of Wernicke's encephalopathy?
Paralysis of the eyes
91
What are less specific signs of Wernicke-Korsakoff Syndrome?
Loss of memory, lack of coordination, lowered level of consciousness
92
How does paralysis of the eyes and lowered consciousness respond to treatment?
Respond to a thiamin injection within 2 days
93
What may not recover if treatment for Wernicke-Korsakoff Syndrome is delayed?
Memory
94
What do the dietary requirements of Thiamin largely depend on?
CHO and energy intake
95
How are the dietary requirements of Thiamin calculated?
Based on total energy intake, assuming an average diet provides around 40% of energy from fat
96
What happens to Thiamin requirements in diets lower in fat?
Requirements will be higher
97
What is the Reference Nutrient Intake (RNI) for Thiamin in males aged 19-54 years in the UK?
1.0 mg/day
98
What is the Reference Nutrient Intake (RNI) for Thiamin in females aged 19-54 years in the UK?
0.8 mg/day
99
How much should the Thiamin intake increase during pregnancy?
+0.1 mg/day
100
How much should the Thiamin intake increase during lactation?
+0.2 mg/day
101
What is the energy intake recommendation for Thiamin?
0.4 mg/1000 kcal
102
What is the yellow pigment associated with Riboflavin?
Flavin ## Footnote Riboflavin is known for its yellow color.
103
Name the two coenzymes associated with Riboflavin.
* Flavin mononucleotide (FMN) * Flavin adenine dinucleotide (FAD) ## Footnote These coenzymes are crucial for various biochemical reactions.
104
How does Riboflavin compare to Thiamin in terms of stability?
More stable than thiamin ## Footnote Riboflavin is resistant to heat, acid, and oxidation.
105
What environmental factor easily breaks down Riboflavin?
Light ## Footnote Despite its stability, Riboflavin is sensitive to light exposure.
106
Fill in the blank: Riboflavin is resistant to _______.
heat, acid, and oxidation
107
What happens during oxidation in a chemical reaction?
A compound loses electrons ## Footnote Oxidation is associated with an increase in oxidation state.
108
What occurs during reduction in a chemical reaction?
A compound gains electrons ## Footnote Reduction is associated with a decrease in oxidation state.
109
What is the role of a reducing agent in a redox reaction?
The reducing agent donates electrons ## Footnote It is oxidized in the process.
110
What is the role of an oxidizing agent in a redox reaction?
The oxidizing agent accepts electrons ## Footnote It is reduced in the process.
111
Oxidation-reduction reactions can also be referred to as _______.
Redox reactions ## Footnote The term 'redox' combines 'reduction' and 'oxidation'.
112
In the context of redox reactions, what does it mean to be oxidized?
To lose electrons ## Footnote This process often involves the addition of oxygen or the removal of hydrogen.
113
In the context of redox reactions, what does it mean to be reduced?
To gain electrons ## Footnote This process often involves the removal of oxygen or the addition of hydrogen.
114
What are the primary functions of water-soluble vitamins?
Oxidation-reduction reactions, citric acid cycle, beta-oxidation pathway, accept hydrogen and electrons.
115
What does FAD form when it accepts electrons?
FADH2
116
What does FMN form when it is reduced?
FMNH2
117
What is the role of FADH2 in cellular respiration?
Delivers electrons to the electron transport chain to produce ATP.
118
Fill in the blank: FAD accepts _______ and electrons.
hydrogen
119
True or False: Water-soluble vitamins do not participate in the citric acid cycle.
False
120
What pathway is associated with the oxidation-reduction reactions of water-soluble vitamins?
Beta-oxidation pathway
121
What is one function of water-soluble vitamins?
Involved in amino acid metabolism - deamination ## Footnote This refers to the process of removing an amino group from an amino acid.
122
Which enzymes are involved in antioxidant activity?
Glutathione reductase, glutathione peroxidase, xanthine oxidase ## Footnote These enzymes play crucial roles in protecting cells from oxidative damage.
123
What is the role of riboflavin in the body?
Involved in antioxidant activity ## Footnote Riboflavin is essential for various biochemical processes, including those that combat oxidative stress.
124
Fill in the blank: Riboflavin is involved in the activity of _______.
antioxidant enzymes ## Footnote These enzymes help to neutralize free radicals in the body.
125
True or False: Riboflavin helps in the removal of amino groups from amino acids.
True ## Footnote This process is essential for amino acid metabolism.
126
What is the significance of unpaired electrons in free radicals?
They contribute to oxidative stress ## Footnote Free radicals with unpaired electrons can cause damage to cells and tissues.
127
What is electron donation in the context of antioxidants?
A mechanism to neutralize free radicals ## Footnote Antioxidants donate electrons to free radicals, stabilizing them and preventing cellular damage.
128
What are some food sources of riboflavin?
Meat, especially liver and kidney Milk and dairy products Eggs Whole-grain products Enriched grain products Mushrooms Fortified breakfast cereals ## Footnote Riboflavin is essential for various bodily functions, including energy production.
129
Which foods contain relatively large amounts of riboflavin?
Milk and eggs ## Footnote These foods are significant sources of riboflavin for the diet.
130
What are the flavin coenzymes associated with riboflavin?
FMN (Flavin Mononucleotide) FAD (Flavin Adenine Dinucleotide) ## Footnote These coenzymes are bound to enzymes and play critical roles in metabolic reactions.
131
What is the color associated with riboflavin?
Intense yellow ## Footnote This characteristic color is why riboflavin is sometimes used as a food coloring (E-101).
132
Fill in the blank: Riboflavin is also known as _______.
Vitamin B2 ## Footnote Vitamin B2 is crucial for energy metabolism and cellular function.
133
What is the deficiency of Riboflavin called?
Ariboflavinosis
134
Is Riboflavin deficiency common or rare?
Rare
135
What condition is often associated with Riboflavin deficiency?
Alcoholism
136
How widespread is Riboflavin in foods?
Widespread in foods
137
What happens to the flavin coenzyme released by enzyme turnover?
It is reutilised
138
Riboflavin deficiency usually exists with what other type of deficiencies?
Other nutrient deficiencies
139
Why is Riboflavin deficiency often seen in alcoholics?
Poor diets
140
Why do most diets provide minimally adequate amounts of Riboflavin?
Because it is widespread in foods
141
What is the efficiency of the reutilisation of Riboflavin in deficiency?
Extremely efficient
142
In Riboflavin deficiency, how much is metabolised?
Only a small amount
143
Riboflavin is involved in the metabolism of how many other B vitamins?
Other 8 vitamins
144
What are the signs/symptoms of B2 Riboflavin deficiency?
* Glossitis - tongue shiny, smooth and inflamed * Angular stomatitis - mouth becomes painful and sore * Cheilosis - swollen, cracked, red lips * Seborrhoeic dermatitis - oil producing glands of the skin become clogged * Anaemia - associated with red cell hypoplasia (underdevelopment) ## Footnote These symptoms highlight the various ways riboflavin deficiency can affect the body.
145
What is another name for B2 Riboflavin deficiency?
Ariboflavinosis ## Footnote Ariboflavinosis is specifically linked to inadequate intake of riboflavin.
146
What is the Recommended Nutrient Intake (RNI) for males aged 19-64 years in the UK?
1.3mg/day
147
What is the Recommended Nutrient Intake (RNI) for females aged 19-64 years in the UK?
1.1mg/day
148
How much should the RNI of riboflavin increase during pregnancy?
+0.3mg/day
149
How much should the RNI of riboflavin increase during lactation?
+0.5mg/day
150
Fill in the blank: The RNI for males aged 19-64 years is _______ mg/day.
1.3
151
Fill in the blank: The RNI for females aged 19-64 years is _______ mg/day.
1.1
152
What are two forms of Vitamin B3?
Nicotinic acid and Nicotinamide
153
What is the coenzyme role of Vitamin B3?
Over 200 metabolic pathways
154
Fill in the blank: Vitamin B3 is also known as _______.
niacin
155
True or False: Nicotinamide is another name for niacin.
True
156
What are the two active compounds of Vitamin B3?
Niacin and Niacinamide
157
What is the full name of NAD+?
Nicotinamide adenine dinucleotide ## Footnote NAD+ is a coenzyme involved in redox reactions.
158
What does NADH stand for?
Nicotinamide adenine dinucleotide phosphate ## Footnote NADH is the reduced form of NAD+.
159
What is the role of NAD and NADP in metabolism?
Cofactors for enzymes involved in fat & carbohydrate metabolism to yield energy ## Footnote They are crucial for oxidative-reduction reactions.
160
How does NAD+ become NADH?
By accepting electrons and hydrogens ## Footnote This process is known as reduction.
161
What type of conditions does NADH operate under?
Aerobic conditions ## Footnote NADH is used in the electron transport chain (ETC).
162
Where is NADPH found in large amounts?
In the liver ## Footnote NADPH plays a role in biosynthetic reactions.
163
What is the reactive moiety of NAD and NADH?
Nicotinamide ## Footnote This component is essential for their function.
164
True or False: NADP+ forms NADPH.
True ## Footnote NADP+ is the oxidized form that gets reduced to NADPH.
165
What is the role of NAD in cellular respiration?
NAD is reduced to NADH during cellular respiration
166
What happens to pyruvate if oxygen is present?
Pyruvate gets converted to acetyl CoA
167
Where do acetyl CoA molecules go after their formation?
They are taken to the electron transport chain (ETC)
168
What occurs to NADH in the electron transport chain?
NADH gets oxidized back to NAD
169
What does the oxidation of NADH in the ETC release?
It releases energy to create ATP
170
What do NADH molecules carry to the electron transport chain?
High-energy electrons
171
Fill in the blank: NADH helps produce _______ in the electron transport chain.
ATP
172
What is the role of NAD+ in cellular metabolism?
NAD+ acts as a coenzyme in redox reactions, helping to convert pyruvate to lactate
173
What can NADH be oxidised back to?
NADH can be oxidised back to NAD+
174
What is produced from pyruvate under anaerobic conditions?
Lactate is produced from pyruvate
175
During high-intensity exercise, what happens to pyruvate?
Pyruvate is converted to lactate
176
What does lactate formation involve?
Lactate formation involves the oxidation of NADH
177
In the context of glycolysis, what is the result of the conversion of glucose?
The conversion of glucose results in pyruvate
178
What cycle involves acetyl CoA and oxaloacetate?
The citric acid cycle
179
What is the significance of niacin in metabolism?
Niacin is part of the coenzyme NAD+, which is essential in metabolic reactions
180
True or False: NADH is produced during glycolysis.
True
181
Fill in the blank: Under anaerobic conditions, pyruvate is converted to _______.
lactate
182
What happens to NADH during the conversion of lactate from pyruvate?
NADH loses electrons and hydrogen to form NAD+
183
What are some food sources of water-soluble vitamins?
Liver, kidney, heart, meat, fish, seafood, enriched grains, whole-grains, fortified cereals, mushrooms, peanuts ## Footnote These sources provide essential nutrients necessary for various bodily functions.
184
What vitamin is associated with the terms niacin, nicotinic acid, and nicotinamide?
Vitamin B3 ## Footnote Niacin is crucial for energy metabolism and DNA repair.
185
What is the mandatory fortification level of flour with nicotinic acid in the UK?
Not less than 1.6 mg/100 g of flour ## Footnote This fortification is intended for restoration purposes.
186
True or False: Wholemeal flour is exempt from the mandatory fortification of nicotinic acid in the UK.
True ## Footnote Certain specified types of flour, including wholemeal, do not require mandatory fortification.
187
Fill in the blank: Water-soluble vitamins include _______.
B vitamins and vitamin C ## Footnote These vitamins are essential for various metabolic processes.
188
What can the nicotinamide ring of NAD be synthesized from?
Tryptophan ## Footnote Tryptophan is an amino acid found in protein-rich animal foods.
189
What is required for the conversion of tryptophan to niacin?
Riboflavin, vitamin B6, and iron ## Footnote A deficiency in any one of these decreases niacin production from tryptophan.
190
What percentage of niacin comes from tryptophan consumption?
Half ## Footnote 60 mg of tryptophan yields 1 mg niacin.
191
How much niacin is produced from 60 mg of tryptophan?
1 mg niacin ## Footnote This is based on the conversion efficiency of tryptophan.
192
How does pregnancy affect the conversion efficiency of tryptophan to niacin?
Increases conversion efficiency ## Footnote This suggests that pregnant individuals may have enhanced nutritional needs.
193
Why is the calculation of dietary intake often ignores niacin content in cereals?
Most niacin in cereals is biologically unavailable ## Footnote This is due to niacytin, which is niacin bound to macromolecules like polysaccharides, peptides, or glycopeptides.
194
What is more important quantitatively for niacin synthesis than dietary preformed niacin?
Synthesis from tryptophan
195
How is niacin content of foods generally expressed?
In mg niacin equivalents (preformed niacin + niacin derived from tryptophan)
196
What are the main dietary sources of niacin?
Rich sources of protein
197
What are the alternative names for niacin?
* Nicotinic acid * Nicotinamide
198
Why is the calculation of dietary intake often ignores niacin content in cereals?
Most niacin in cereals is biologically unavailable ## Footnote This is due to niacytin, which is niacin bound to macromolecules like polysaccharides, peptides, or glycopeptides.
199
What is more important quantitatively for niacin synthesis than dietary preformed niacin?
Synthesis from tryptophan
200
How is niacin content of foods generally expressed?
In mg niacin equivalents (preformed niacin + niacin derived from tryptophan)
201
What are the main dietary sources of niacin?
Rich sources of protein
202
What are the alternative names for niacin?
* Nicotinic acid * Nicotinamide
203
What is the introduction of maize described as?
A convenient high-yielding staple food
204
What is Pellagra commonly referred to as?
'Red sickness'
205
What do the components of the word Pellagra mean?
Pelle (skin), agra (tough)
206
What are the three D's associated with Pellagra?
* Dermatitis * Dementia or depressive psychosis * Diarrhoea
207
What vitamin deficiency is linked to Pellagra?
Niacin deficiency
208
What severe consequence can arise from Niacin deficiency?
Severe cases cause death
209
What other deficiencies contribute to Pellagra?
Deficiencies of iron and B vitamins
210
What vitamin deficiency is associated with Pellagra?
Deficiency in tryptophan and niacin ## Footnote Pellagra is primarily caused by a lack of these nutrients.
211
What dietary process releases niacin from corn?
Soaking corn in lime ## Footnote This traditional method improves the bioavailability of niacin.
212
What has contributed to the lower incidence of Pellagra today?
Enrichment of bread flour and other cereal grains with niacin ## Footnote This public health measure has significantly reduced cases of Pellagra.
213
What are the other causes of Pellagra aside from niacin deficiency?
Deficiency in either riboflavin or vitamin B6 when intake of tryptophan and preformed niacin are marginal ## Footnote These deficiencies can exacerbate the risk of developing Pellagra.
214
How does excessive intake of leucine affect tryptophan metabolism?
Inhibits tryptophan metabolism ## Footnote High leucine levels can disrupt the conversion of tryptophan into niacin.
215
True or False: Pellagra can occur due to a deficiency in riboflavin.
True ## Footnote Riboflavin deficiency can contribute to the risk of Pellagra under specific dietary conditions.
216
What is the RNI for Niacin in males aged 19-64 years in the UK?
16.5 mg/day
217
What is the RNI for Niacin in females aged 19-64 years in the UK?
13.2 mg/day
218
Is there an increment in the RNI for Niacin during pregnancy?
No increment
219
What is the increment in RNI for Niacin during lactation?
+2 mg/day
220
What dietary component can meet the regulations for Niacin intake without preformed niacin?
Tryptophan
221
Fill in the blank: The RNI for Niacin in females aged 19-64 years is _______.
13.2 mg/day
222
True or False: The RNI for Niacin increases during pregnancy.
False
223
What is the recommended intake of Niacin for males aged 19-64 years in the UK?
16.5 mg/day
224
What are the side effects of niacin toxicity?
Dilation of blood vessels: * Flushing * Itching * Tingling ## Footnote High levels (>500 mg/day) can cause more serious side effects.
225
What serious side effects can occur with high levels of niacin?
Liver toxicity Impaired glucose tolerance ## Footnote Megadoses of niacin are sometimes prescribed to increase HDL and lower LDL cholesterol.
226
What is the mechanism of action of niacin in raising HDL?
Decreasing the fractional catabolic rate of HDL-apo Al without affecting the synthetic rates ## Footnote Niacin selectively increases HDL subfraction without apo All, which is cardioprotective in patients with low HDL.
227
What percentage of total HDL protein does Apolipoprotein A-II (apo A-II) account for?
Approximately 20% ## Footnote Apo A-II is the second most abundant protein on HDL.
228
Fill in the blank: Niacin is sometimes prescribed in megadoses to increase _______ and lower _______.
[HDL] [LDL cholesterol]
229
True or False: Niacin affects the synthetic rates of HDL-apo Al.
False ## Footnote Niacin decreases the fractional catabolic rate without affecting synthetic rates.
230
What are the three forms of vitamin B6?
Pyridoxal, pyridoxine, and pyridoxamine ## Footnote These forms can be phosphorylated.
231
What happens to vitamin B6 in food?
Food contains phosphorylated forms ## Footnote These forms are converted during digestion.
232
What is the role of the liver in vitamin B6 metabolism?
All forms are converted to pyridoxal phosphate (PLP) ## Footnote PLP is the active coenzyme form.
233
What is pyridoxal phosphate (PLP)?
The active coenzyme form of vitamin B6 ## Footnote Required for various enzymatic reactions.
234
Fill in the blank: Digestion removes the _______ group from phosphorylated forms of vitamin B6.
phosphate
235
True or False: Pyridoxine is the only form of vitamin B6 found in food.
False ## Footnote There are three forms: pyridoxal, pyridoxine, and pyridoxamine.
236
What is the significance of pyridoxal phosphate in human metabolism?
It acts as a coenzyme in various metabolic reactions ## Footnote Essential for amino acid metabolism and neurotransmitter synthesis.
237
What is the main active form of vitamin B6?
Pyridoxal phosphate (PLP) ## Footnote PLP is essential for over 100 enzymatic reactions in the body.
238
List the functions supported by pyridoxal phosphate (PLP)
* Protein metabolism * Blood cell synthesis * CHO metabolism * Neurotransmitter synthesis * Homocysteine regulation * Steroid hormone deactivation ## Footnote PLP plays a crucial role in several metabolic pathways.
239
True or False: Pyridoxal phosphate (PLP) is involved in the transfer of amino groups.
True ## Footnote PLP facilitates the transfer of amino groups, carboxyl groups, or water.
240
Fill in the blank: Pyridoxal phosphate (PLP) supports more than _______ enzymes.
100 ## Footnote This highlights its importance in various biochemical processes.
241
What is the chemical name for Vitamin B6?
Pyridoxine
242
What role does PLP play in amino acid metabolism?
Part of amino transferase/transaminase enzyme
243
What is the function of transaminase?
Assists in transfer of amino group from amino acid to keto acid to produce new amino acid
244
What happens to non-essential amino acids without Vitamin B6?
They become conditionally essential
245
Fill in the blank: PLP is part of the _______ enzyme.
Amino transferase/transaminase
246
True or False: Vitamin B6 is necessary for the production of non-essential amino acids.
True
247
What is the role of vitamin B6 (pyridoxine) in glycogen breakdown?
Vitamin B6 (pyridoxine) plays a role in breaking down glycogen into glucose in the liver and muscle.
248
What is required for glycogen phosphorylase to function?
Pyridoxal phosphate (PLP) is required for glycogen phosphorylase to function.
249
Fill in the blank: Glycogen phosphorylase requires _______ to function.
PLP
250
What is the role of vitamin B6 (pyridoxine) in glycogen breakdown?
Vitamin B6 (pyridoxine) plays a role in breaking down glycogen into glucose in the liver and muscle.
251
What is required for glycogen phosphorylase to function?
Pyridoxal phosphate (PLP) is required for glycogen phosphorylase to function.
252
Fill in the blank: Glycogen phosphorylase requires _______ to function.
PLP
253
What is the chemical name for vitamin B6?
Pyridoxine
254
What type of anemia is associated with vitamin B6 deficiency?
Microcytic, Hypochromic Anemia
255
What role does PLP play in blood cell synthesis?
Supports synthesis of white blood cells and red blood cells
256
What is crucial for the synthesis of haemoglobin?
Vitamin B6
257
What happens to oxygen binding in haemoglobin without vitamin B6?
Oxygen cannot bind, leading to microcytic hypochromic anemia
258
What are the characteristics of red blood cells in microcytic hypochromic anemia?
Small and lack sufficient haemoglobin
259
What neurotransmitter is associated with pleasure and reward?
Dopamine ## Footnote Dopamine plays a key role in the brain's reward system and is linked to feelings of pleasure.
260
Which neurotransmitter is linked to mood and well-being?
Serotonin ## Footnote Serotonin is also known as pyridoxine and is crucial for mood regulation.
261
What is the role of Gamma-amino butyric acid (GABA)?
Inhibitory neurotransmitter ## Footnote GABA helps to reduce neuronal excitability throughout the nervous system.
262
What can deficiency in certain neurotransmitters cause?
Neurological symptoms ## Footnote Symptoms may include depression, headache, confusion, and convulsions.
263
Fill in the blank: Dopamine is related to _______.
pleasure and reward
264
Which neurotransmitter is associated with learning and attention?
Dopamine ## Footnote Dopamine is not only linked to pleasure but also plays a significant role in learning processes.
265
True or False: Serotonin is involved in appetite regulation.
True ## Footnote Serotonin influences various functions including appetite and mood.
266
What is the primary function of noreadrenaline?
Arousal and attention ## Footnote Noreadrenaline is involved in the body's response to stress and helps maintain alertness.
267
Fill in the blank: A deficiency in serotonin can lead to _______.
depression
268
List three functions of dopamine.
* Pleasure * Reward * Learning
269
What role does serotonin play in sleep?
Regulates sleep patterns ## Footnote Serotonin contributes to the regulation of sleep cycles.
270
Fill in the blank: _______ is associated with social rank and well-being.
Dopamine
271
What symptoms can arise from a deficiency in neurotransmitters?
* Depression * Headache * Confusion * Convulsions
272
What is the role of Vitamin B6 in homocysteine regulation?
Vitamin B6 is involved in converting homocysteine to cysteine. ## Footnote This process is facilitated by two PLP-dependent enzymes.
273
High homocysteine levels are linked to which health condition?
Heart disease. ## Footnote Elevated homocysteine is a risk factor for cardiovascular diseases.
274
How do folate and Vitamin B12 affect homocysteine levels?
They reduce homocysteine levels by converting it to methionine. ## Footnote This conversion helps lower the risk of heart disease.
275
What dietary sources can offer protective effects against heart disease?
Fruit and vegetables, whole grains, and fish. ## Footnote These foods are rich in vitamins and nutrients that contribute to heart health.
276
Fill in the blank: Vitamin B12 is stored in the body, so intake doesn't really affect _______.
homocysteine levels.
277
What is the function of S-Adenosylmethionine?
It acts as a methyl donor in various methylation reactions. ## Footnote This includes the conversion of homocysteine to methionine.
278
What is the effect of B6 intake on homocysteine levels?
B6 reduces homocysteine levels by converting it to cysteine.
279
True or False: Folic acid supplementation has been shown to reduce the risk of cardiovascular events through reduced homocysteine levels.
False. ## Footnote Research indicates that folic acid supplementation does not significantly lower cardiovascular event risk.
280
What are the two forms of homocysteine in the body?
S-Adenosylhomocysteine and homocysteine. ## Footnote These are involved in various metabolic processes.
281
What vitamin is also known as pyridoxine?
Vitamin B6.
282
How does the intake of folate, B6, and B12 influence homocysteine levels?
They help to lower homocysteine levels through conversion processes.
283
What is the significance of cystathionine in the context of homocysteine metabolism?
Cystathionine is a product formed during the conversion of homocysteine to cysteine.
284
List the factors influencing homocysteine levels.
* Intake of folate * Intake of Vitamin B6 * Intake of Vitamin B12.
285
What type of hormone diffuses through the plasma membrane?
Lipid-soluble hormone
286
Where does a lipid-soluble hormone bind after diffusing through the plasma membrane?
Cytoplasm
287
What is formed when a hormone binds with a receptor in the cytoplasm?
Receptor-hormone complex
288
What does the receptor-hormone complex do after formation?
Enters the nucleus and triggers gene transcription
289
What vitamin is referred to as pyridoxine?
B6
290
What is the final product of the steroid hormone mechanism of action?
Proteins that alter cell activity
291
Fill in the blank: When the hormone enters the cytoplasm, it binds to the receptor, forming a _______.
hormone-receptor complex
292
True or False: The receptor-hormone complex binds to DNA to initiate transcription.
True
293
What is transcribed from DNA during the steroid hormone mechanism?
mRNA
294
What process occurs after mRNA is transcribed?
Translation
295
What does the activated protein do in the context of hormone action?
Alters cell activity
296
What is the role of PLP in steroid hormone deactivation?
PLP removes hormone-receptor complex from DNA binding, decreasing action of hormones.
297
What vitamin is referred to as B6?
Pyridoxine.
298
What are the effects of B6 deficiency?
* Increased sensitivity and responsiveness of cells to low concentrations of steroid hormones * Increased risk for hormone-dependent cancers.
299
Which hormones are mentioned in relation to B6 deficiency?
* Oestrogen * Testosterone * Cortisol.
300
True or False: B6 deficiency decreases the risk for hormone-dependent cancers.
False.
301
What is the role of B6 (pyridoxine) in steroid hormone deactivation?
PLP removes hormone-receptor complex from DNA binding and decreases action of hormones
302
What are the effects of B6 deficiency on steroid hormones?
Increased sensitivity and responsiveness of cells to low concentrations of steroid hormones
303
Which steroid hormones are impacted by B6 deficiency?
* Oestrogen * Testosterone * Cortisol
304
What is a potential risk associated with B6 deficiency?
Increased risk for hormone-dependent cancers
305
What is the RNI for males aged 19-64 years for vitamin B6 (pyridoxine)?
1.4 mg/day
306
What is the RNI for females aged 19-64 years for vitamin B6 (pyridoxine)?
1.2 mg/day
307
Is there an increase in vitamin B6 requirements during pregnancy or lactation?
No
308
Why might individuals on high protein diets need more vitamin B6?
Due to its role in protein metabolism
309
What is another name for Vitamin B6?
pyridoxine
310
What percentage of Vitamin B6 in food is bioavailable?
75%
311
List three food sources of Vitamin B6.
* Fortified cereals * Meat, fish and poultry * Starchy vegetables and white potatoes
312
Which type of fruits are good sources of Vitamin B6?
Non-citrus fruits, bananas
313
What organ meat is particularly high in Vitamin B6?
Beef liver
314
Name two other food sources of Vitamin B6 besides organ meats.
* Sunflower seeds * Eggs
315
What type of grains are a source of Vitamin B6?
Whole-grains
316
True or False: Vitamin B6 is particularly sensitive to heat.
True
317
What type of anemia is characterized by microcytic and hypochromic red blood cells?
Microcytic hypochromic anemia ## Footnote This type of anemia results from various deficiencies, most commonly iron deficiency.
318
Which vitamin deficiency is associated with neurological symptoms and increased levels of homocysteine?
B6 (pyridoxine) deficiency ## Footnote This deficiency is very rare but can lead to serious health issues.
319
What skin condition is linked with B6 deficiency?
Seborrheic dermatitis ## Footnote This condition involves scaly patches and red skin, primarily on the scalp.
320
What is a potential consequence of increased blood levels of homocysteine?
Increased sensitivity to hormones - hormone-dependent cancers ## Footnote Elevated homocysteine levels are associated with various health risks.
321
Which amino acids are involved in the abnormal metabolism due to B6 deficiency?
Methionine and tryptophan ## Footnote These amino acids are crucial for various metabolic processes.
322
True or False: B6 deficiency is common.
False ## Footnote B6 deficiency is considered very rare.
323
What is one potential toxicity effect of megadoses of B6 supplements?
Irreversible nerve damage and inability to walk ## Footnote Megadoses can also cause upset stomach, headache, sleepiness, and tingling sensations.
324
List three medicinal uses of B6 (pyridoxine).
* Premenstrual syndrome * Morning sickness of pregnancy * Carpal tunnel syndrome
325
True or False: B6 supplements can be taken without medical supervision.
False
326
Fill in the blank: Megadoses of B6 can cause _______.
irreversible nerve damage
327
What are common side effects of B6 toxicity?
* Upset stomach * Headache * Sleepiness * Tingling sensations
328
What is the most stable form of folate?
Folic acid ## Footnote Folic acid is commonly used in supplements and for fortification.
329
What are the three parts that make up folic acid?
1. Pteridine ring 2. Para-amino-benzoic acid 3. Glutamic acid
330
Folic acid is primarily used in which applications?
Supplements and fortification ## Footnote Folic acid is used to prevent deficiencies and support health.
331
Fill in the blank: Folic acid is the _______ form of folate.
most stable
332
True or False: Folic acid is the form of folate that occurs naturally in foods.
False ## Footnote The natural forms of folate are found in foods, while folic acid is synthetic.
333
What is the coenzyme form of Folate?
Tetrahydrofolic acid (THFA) ## Footnote THFA is involved in the transfer of 1-carbon units.
334
List three functions of Folate.
* DNA synthesis * Cell division * Amino acid metabolism ## Footnote Folate is essential for various metabolic processes.
335
What is one role of Folate in red blood cell maturation?
Supports red blood cell synthesis ## Footnote Folate helps in the maturation of red blood cells.
336
How does Folate relate to neural tube defects?
Folate deficiency is associated with neural tube defects ## Footnote Adequate Folate intake is crucial during pregnancy.
337
Which vitamins work together with Folate to control homocysteine levels?
B6 and B12 ## Footnote These vitamins are important for amino acid metabolism and homocysteine regulation.
338
What are the food sources of Folate?
* Dark green leafy vegetables * Liver * Fortified breakfast cereals * Whole-grain products * Wheatgerm * Legumes * Sunflower seeds * Some fruits and vegetables (especially broccoli, spinach, avocados, sprouts, asparagus) * Orange juice / other citrus fruits ## Footnote Folate is a water-soluble vitamin important for DNA synthesis and repair, and is particularly crucial during periods of rapid growth such as pregnancy and infancy.
339
What are the food sources of Folate?
* Dark green leafy vegetables * Liver * Fortified breakfast cereals * Whole-grain products * Wheatgerm * Legumes * Sunflower seeds * Some fruits and vegetables (especially broccoli, spinach, avocados, sprouts, asparagus) * Orange juice / other citrus fruits ## Footnote Folate is a water-soluble vitamin important for DNA synthesis and repair, and is particularly crucial during periods of rapid growth such as pregnancy and infancy.
340
What is the RNI for Folate (B9) for males aged 19-64 years in the UK?
200 ug/day
341
What is the RNI for Folate (B9) for females aged 19-64 years in the UK?
200 ug/day
342
What is the additional RNI for Folate (B9) during pregnancy?
100 ug/day
343
What is the additional RNI for Folate (B9) during lactation?
60 ug/day
344
What vitamin is linked to preventing neural tube defects during pregnancy?
Folate (B9) ## Footnote Low folate status is strongly linked to birth defects, specifically neural tube defects.
345
What is the recommended daily intake of folate to prevent birth defects?
400 ug folate per day ## Footnote This intake is recommended before and during pregnancy.
346
What type of supplementation is advised for women who are pregnant or may become pregnant?
Supplements of folate ## Footnote It is crucial for preventing birth defects.
347
Is grain fortification with folate mandatory in the United States?
Yes ## Footnote The US mandates fortification of grains with folate.
348
What is the status of folate fortification in the UK?
Recommended to be mandatory but not yet mandatory ## Footnote The SACN has recommended mandatory fortification.
349
Fill in the blank: 50-70% of neural tube defects could be prevented by _______.
400 ug folate per day
350
What is folate (B9) necessary for?
Red blood cell production and neural tube formation ## Footnote Folic acid, the synthetic form of folate, plays a critical role in these physiological processes.
351
What is the most prevalent vitamin deficiency?
Folate deficiency ## Footnote This deficiency is often linked to poor nutrition.
352
What are some causes of folate deficiency?
Poor nutrition, intestinal malabsorption, medications ## Footnote These factors can hinder the body's ability to absorb or utilize folate.
353
What health conditions can folate deficiency contribute to?
* Anaemia * Atherosclerosis * Neural tube defects * Adverse pregnancy outcomes * Neuropsychiatric disorders ## Footnote Each of these conditions has significant health implications, particularly during pregnancy and development.
354
True or False: Folate deficiency is only caused by poor dietary intake.
False ## Footnote Other factors such as medications and intestinal malabsorption also play a role.
355
What are the conditions that can lead to folate deficiency?
Inadequate consumption, inadequate folate absorption, increased folate requirements, impaired folate utilisation, altered folate metabolism, excessive folate excretion ## Footnote Each condition affects the body's ability to maintain adequate levels of folate, which is essential for various bodily functions.
356
What is the chemical name of Folate?
Vitamin B9 ## Footnote Folate is also known as Vitamin B9.
357
Which vitamins work together with Folate to reduce homocysteine levels?
B6 and B12 ## Footnote These vitamins play a crucial role in the metabolism of homocysteine.
358
What is the consequence of inadequate folate intake?
Increased homocysteine levels ## Footnote High homocysteine levels are linked to various health issues, including heart disease.
359
What effect does the fortification of grain products have on blood levels?
Increased blood folate levels and decreased blood homocysteine levels ## Footnote Fortification is a public health strategy to improve nutrient intake.
360
True or False: Folate intake is associated with protection against heart disease.
True ## Footnote Adequate folate levels may help protect against cardiovascular diseases.
361
Fill in the blank: Folate is essential for reducing _______ levels in the body.
homocysteine ## Footnote Homocysteine is an amino acid linked to heart disease risk.
362
What is megaloblastic anemia?
A type of anemia characterized by the presence of large, fragile, immature red blood cells called megaloblasts. ## Footnote It results from deficiencies in folate and vitamin B12, which are essential for DNA synthesis and cell growth.
363
What vitamins are required for DNA synthesis and cell growth?
Folate and vitamin B12. ## Footnote Both are critical for the normal functioning and division of red blood cells.
364
What happens to red blood cells in megaloblastic anemia?
They cannot grow and mature normally, developing into large, fragile, immature cells called megaloblasts that may mature into macrocytes. ## Footnote This abnormal maturation leads to a decreased ability of the body to carry oxygen.
365
True or False: A deficiency in folate shows up quickly in red blood cells.
True. ## Footnote This is due to the rapid division of red blood cells.
366
Fill in the blank: Red blood cells are required to _______ rapidly.
[divide] ## Footnote The rapid division of red blood cells is crucial for maintaining adequate oxygen transport in the body.
367
What type of cells develop from megaloblasts?
Macrocytes. ## Footnote These are larger than normal red blood cells and indicate a problem with cell maturation.
368
What is the consequence of megaloblastic anemia on the body's ability?
The body's ability to carry oxygen decreases. ## Footnote This can lead to symptoms such as fatigue and weakness.
369
What are required for DNA synthesis and cell growth?
Folate and B12 ## Footnote Folate and vitamin B12 are essential for the replication of DNA and normal cell division.
370
What happens to red blood cell precursors when deficient in folate or B12?
They cannot form new DNA and cannot divide ## Footnote This leads to the inability of red blood cells to grow and mature normally.
371
What do red blood cell precursors develop into when they cannot divide?
Megaloblasts ## Footnote These are large, fragile, immature cells that result from the failure to divide.
372
What are macrocytes?
Abnormally large red blood cells ## Footnote Macrocytes are a result of the maturation of megaloblasts.
373
What condition results from the proliferation of megaloblasts and decrease of normal red blood cells?
Megaloblastic anemia ## Footnote This condition leads to reduced oxygen-carrying capacity and symptoms like weakness and fatigue.
374
Why does a deficiency in folate or B12 show up quickly?
Red blood cells divide rapidly ## Footnote Rapidly dividing cells are more susceptible to nutrient deficiencies.
375
Which other cells are affected by the deficiency of folate or B12?
Cells lining the GI tract and white blood cells ## Footnote These cells also divide rapidly and can be impacted by the deficiency.
376
Fill in the blank: When red blood cells cannot divide, they keep growing and develop into _______.
megaloblasts
377
True or False: A deficiency in folate or B12 can lead to normal red blood cell maturation.
False ## Footnote Deficiencies prevent normal maturation and division of red blood cells.
378
What is one of the primary symptoms of megaloblastic anemia?
Weakness and fatigue ## Footnote These symptoms result from the body's reduced ability to carry oxygen.
379
What are neural tube defects?
Birth defects of the brain, spine, or spinal cord.
380
When does the neural tube close during fetal development?
About 4 weeks after conception.
381
What is spina bifida?
A condition where the neural tube fails to encase the spinal cord during early fetal development.
382
What is anencephaly?
The absence of a major portion of the brain, skull, and scalp that occurs during embryonic development.
383
What causes anencephaly?
A neural tube defect that occurs when the rostral end of the neural tube fails to close.
384
What is the estimated incidence of neural tube defects?
Affects 1-9 per 1000 infants worldwide.
385
What impact has mandatory fortification had on neural tube defects?
Estimated to have reduced incidence by 26%.
386
Fill in the blank: Neural tube defects occur when the neural tube fails to _______.
encase the spinal cord.
387
True or False: Anencephaly is considered a type of cephalic disorder.
True.
388
What is the role of Folate (Bg) in the body?
Synthesis, repair and function of DNA and RNA
389
What type of cancer is a high-folate diet particularly protective against?
Colorectal cancer
390
What is unclear regarding Folate supplementation?
The role of supplementation
391
What type of studies suggest that a high-folate diet may protect against cancer?
Observational studies
392
Is there ongoing research related to Folate and cancer?
Yes, active scientific research
393
What is the role of Folate (Bg) in the body?
Synthesis, repair and function of DNA and RNA
394
What type of cancer is a high-folate diet particularly protective against?
Colorectal cancer
395
What is unclear regarding Folate supplementation?
The role of supplementation
396
What type of studies suggest that a high-folate diet may protect against cancer?
Observational studies
397
Is there ongoing research related to Folate and cancer?
Yes, active scientific research
398
What can excess folate prevent?
Formation of altered red blood cells ## Footnote Excess folate may lead to complications in individuals with B12 deficiency.
399
What neurological problems can excess folate exaggerate?
Problems associated with B12 deficiency ## Footnote Excessive folate intake can worsen neurological issues in those lacking B12.
400
What are potential side effects of folate supplements?
Hives or respiratory distress ## Footnote Some individuals may have allergic reactions to folate supplements.
401
True or False: Excess folate can mask B12 deficiency.
True ## Footnote This masking effect can lead to undiagnosed B12 deficiency.
402
What can excess folate prevent?
Formation of altered red blood cells ## Footnote Excess folate may lead to complications in individuals with B12 deficiency.
403
What neurological problems can excess folate exaggerate?
Problems associated with B12 deficiency ## Footnote Excessive folate intake can worsen neurological issues in those lacking B12.
404
What are potential side effects of folate supplements?
Hives or respiratory distress ## Footnote Some individuals may have allergic reactions to folate supplements.
405
True or False: Excess folate can mask B12 deficiency.
True ## Footnote This masking effect can lead to undiagnosed B12 deficiency.
406
What is Cobalamin commonly known as?
Vitamin B12 ## Footnote Cobalamin is essential for various bodily functions.
407
How does Cobalamin differ from other B vitamins in terms of storage?
Body stores large amounts ## Footnote This is unlike other B vitamins that are not stored in significant amounts.
408
Do plants produce Cobalamin?
No ## Footnote Cobalamin is not produced by plants.
409
What are the cobalt-containing compounds collectively known as?
Cobalamin ## Footnote Cobalamin refers to various compounds containing cobalt.
410
List three types of Cobalamin supplements.
* Cyanocobalamin * Hydroxocobalamin * Methylcobalamin ## Footnote These supplements are used to increase vitamin B12 levels.
411
What is the function of Cobalamin (B12)?
Takes away methyl group from THFA and donates methyl group to homocysteine to form methionine.
412
What does THFA stand for?
Tetrahydrofolic acid.
413
What is the role of Folate?
Involved in the conversion of homocysteine to methionine.
414
Fill in the blank: Cobalamin donates a methyl group to _______.
homocysteine.
415
True or False: Cobalamin is also known as Vitamin B12.
True.
416
What is the significance of methionine in the body?
It is an essential amino acid involved in various metabolic processes.
417
List two functions of Cobalamin (B12).
* Takes away methyl group from THFA * Donates methyl group to homocysteine to form methionine.
418
What is the chemical name of Vitamin B12?
Cobalamin
419
What is the role of SAH in metabolism?
SAH is involved in various metabolic pathways.
420
What does SAM allow THFA to do?
Change into its methylene form, active in many metabolic pathways.
421
What protective function does Cobalamin serve?
Maintains the myelin sheath that surrounds nerve fibers.
422
What is the importance of the myelin sheath?
It is a protective coat for healthy nerve fibers.
423
What metabolic process does Cobalamin facilitate regarding fatty acids?
Rearranges carbon atoms in fatty acid chains to prepare them for the citric acid cycle.
424
What does MTRR stand for?
Methionine Synthase Reductase
425
What is the abbreviation for Methionine Synthase?
MTR
426
What does MTHPR represent?
Methylenetetrahydrofolate Reductase
427
What do salivary glands produce that is related to vitamin B12?
R-protein ## Footnote R-protein is involved in the absorption of vitamin B12.
428
What is the role of intrinsic factor in vitamin B12 absorption?
Intrinsic factor is released by stomach cells and aids in the absorption of B12 ## Footnote It is crucial for binding with B12 in the stomach.
429
In which part of the digestive system does the B12-IF complex bind to an intestinal cell receptor?
Ileum ## Footnote The ileum is the final section of the small intestine.
430
What happens to B12 after it enters circulation?
It is bound to transcobalamin ## Footnote Transcobalamin is a transport protein for vitamin B12.
431
Fill in the blank: The absorption of vitamin B12 is a _______ process.
complex
432
What partially degrades R-protein during the absorption of B12?
Pancreatic enzymes ## Footnote This degradation releases B12 to bind with intrinsic factor.
433
What is the time frame for B12 to enter circulation after absorption?
3-4 hours ## Footnote This timeframe indicates the duration for B12 to be processed after binding.
434
True or False: B12 binds with R-protein in the ileum.
False ## Footnote B12 binds with R-protein in the stomach, not the ileum.
435
What is Cobalamin also known as?
B12
436
What factors impair the absorption of Cobalamin?
* Lack of R-protein * Lack of pancreatic enzymes * Lack of intrinsic factor * Removal of ileum or stomach * Large growth of bacteria in stomach * Presence of tapeworm * Reduced gastric acid production
437
True or False: Lack of intrinsic factor can impair Cobalamin absorption.
True
438
Fill in the blank: The removal of the _______ can impair the absorption of Cobalamin.
ileum
439
What condition related to gastric acid can impair Cobalamin absorption?
Atrophic gastritis or acid-inhibiting medications
440
What is one potential cause of reduced gastric acid production that can affect Cobalamin absorption?
Acid-inhibiting medications
441
List two factors that can lead to impaired absorption of Cobalamin.
* Lack of R-protein * Large growth of bacteria in stomach
442
What is Cobalamin also known as?
Vitamin B12 ## Footnote Cobalamin is essential for various bodily functions and is commonly found in animal-derived foods.
443
What are the primary food sources of Vitamin B12?
* Animal-derived foods (meat) * Liver * Fortified cereals * Fortified soy products * Milk and milk products * Shellfish and fish * Nutritional yeast ## Footnote Animals obtain B12 from bacteria in their food or intestinal bacteria.
444
What percentage of dietary B12 is biologically available?
50% ## Footnote This refers to the fraction of Vitamin B12 that the body can effectively use.
445
True or False: All naturally occurring B12 originates from bacteria.
True ## Footnote Bacteria are the primary source of Vitamin B12 in the food chain.
446
Which types of fish are known to be good sources of Vitamin B12?
* Mackerel * Sardines ## Footnote These fish are particularly rich in Vitamin B12.
447
What is the requirement for Cobalamin (B12) for males aged 19-64 years in the UK?
1.5 ug/day
448
What is the requirement for Cobalamin (B12) for females aged 19-64 years in the UK?
1.5 ug/day
449
Is there an increase in Cobalamin (B12) requirement during pregnancy?
No increase
450
What is the increase in Cobalamin (B12) requirement during lactation?
+0.5 ug/day
451
What are water-soluble vitamins?
Vitamins that dissolve in water and are not stored in the body.
452
What is the storage duration of Cobalamin (B12) in the liver?
Storage in liver can last 2 years.
453
What are the symptoms of Cobalamin deficiency?
Symptoms may not appear for >12 years.
454
Who is primarily at risk for Cobalamin deficiency?
Only vegans and vegetarians who don't consume dairy products.
455
What are the main causes of Cobalamin deficiency?
Inadequate intake and impaired absorption.
456
What methods are used to deliver Cobalamin to the bloodstream?
Injections, megadoses, and nasal sprays.
457
Fill in the blank: Symptoms of Cobalamin deficiency may not appear for ______ years.
>12
458
True or False: Cobalamin can be stored in the liver for up to 5 years.
False
459
What is a key characteristic of water-soluble vitamins?
They are not stored in the body.
460
What is the primary dietary concern for vegans regarding Cobalamin?
They may not consume dairy products.
461
What are water-soluble vitamins?
Vitamins that dissolve in water and are not stored in the body.
462
What is the storage duration of Cobalamin (B12) in the liver?
Storage in liver can last 2 years.
463
What are the symptoms of Cobalamin deficiency?
Symptoms may not appear for >12 years.
464
Who is primarily at risk for Cobalamin deficiency?
Only vegans and vegetarians who don't consume dairy products.
465
What are the main causes of Cobalamin deficiency?
Inadequate intake and impaired absorption.
466
What methods are used to deliver Cobalamin to the bloodstream?
Injections, megadoses, and nasal sprays.
467
Fill in the blank: Symptoms of Cobalamin deficiency may not appear for ______ years.
>12
468
True or False: Cobalamin can be stored in the liver for up to 5 years.
False
469
What is a key characteristic of water-soluble vitamins?
They are not stored in the body.
470
What is the primary dietary concern for vegans regarding Cobalamin?
They may not consume dairy products.
471
What is the primary vitamin associated with Cobalamin?
B12 ## Footnote Cobalamin is also known as Vitamin B12.
472
What are the types of cells affected by B12 deficiency?
Megaloblasts and macrocytes ## Footnote These are large, immature red blood cells associated with anemia.
473
What type of anemia is specifically caused by a deficiency of B12?
Megaloblastic anemia ## Footnote This type of anemia results from impaired DNA synthesis.
474
What are the neurological effects of B12 deficiency?
Myelin sheath swelling and breakdown, brain abnormalities, spinal cord degeneration ## Footnote These effects can lead to severe neurological symptoms.
475
List two symptoms of B12 deficiency.
* Tingling and numbness in extremities * Cognitive changes ## Footnote Cognitive changes may include loss of concentration and memory loss.
476
How does treatment with folate affect red blood cell production in B12 deficiency?
Normalises red blood cell production but worsens neurological damage ## Footnote This treatment can mask the deficiency and lead to further complications.
477
What are the cognitive changes associated with B12 deficiency?
* Loss of concentration * Memory loss * Disorientation * Dementia ## Footnote These changes can severely impact daily functioning.
478
True or False: Folate deficiency can cause myelin sheath damage.
False ## Footnote Myelin sheath damage is specifically associated with B12 deficiency.
479
What can result from incorrect treatment of B12 megaloblastic anemia?
Worsened neurological damage ## Footnote Incorrect treatment can lead to irreversible effects depending on the duration of deficiency.
480
What is a potential outcome of neurological damage caused by B12 deficiency?
May be reversible, depends on duration ## Footnote Early intervention can improve outcomes.
481
Fill in the blank: Folate deficiency can cause _______ and cognitive defects.
depression ## Footnote This highlights the psychological effects of folate deficiency.
482
What is a key difference between folate deficiency and B12 deficiency?
B12 deficiency causes myelin sheath swelling, while folate deficiency does not ## Footnote This distinction is crucial for diagnosis and treatment.
483
What does the Active-B12 assay detect?
Levels of serum holotranscobalamin (holoTC) ## Footnote HoloTC is the metabolically available component of vitamin B12.
484
What is holoC used as a marker for?
Vitamin B12 deficiency
485
Fill in the blank: HoloC is the _______ component of vitamin B12.
metabolically available
486
What are the two biologically active forms of Vitamin C?
Ascorbic acid (reduced form) and Dehydroascorbic acid (oxidised form) ## Footnote These forms play different roles in biological functions.
487
Can humans synthesize Vitamin C?
No, humans are unable to synthesize Vitamin C ## Footnote Many animals can produce their own Vitamin C.
488
How does the requirement for Vitamin C differ between humans and most animals?
Humans require less Vitamin C than most animals ## Footnote This is due to the inability to synthesize it.
489
What is a primary function of Vitamin C?
Functions as an antioxidant ## Footnote It helps protect cells from damage caused by free radicals.
490
Is Vitamin C a coenzyme?
No, Vitamin C is not a coenzyme ## Footnote It only indirectly activates enzymes.
491
What enzyme do humans lack that prevents them from synthesizing Vitamin C?
Gulonolactone oxidase ## Footnote This enzyme is essential for the synthesis of Vitamin C.
492
What role does Vitamin C play as an antiesiderit?
Acts as a reducing agent ## Footnote It donates electrons or hydrogen ions in reactions.
493
What vitamin is involved in collagen synthesis?
Vitamin C (ascorbic acid) ## Footnote Collagen is a major protein in connective tissues and maintains the structure of the body.
494
What is the most abundant protein in our bodies?
Collagen ## Footnote Collagen provides strength and flexibility to the body's structure.
495
What role do proteins play in the body?
They wrap around like a rope to give strength and flexibility ## Footnote Proteins are essential for maintaining the structural integrity of tissues.
496
Fill in the blank: Vitamin C is also known as _______.
[ascorbic acid]
497
True or False: Vitamin C is not involved in collagen synthesis.
False ## Footnote Vitamin C is crucial for the synthesis of collagen, which is vital for connective tissues.
498
What is Vitamin C also known as?
Ascorbic acid ## Footnote Vitamin C is a water-soluble vitamin essential for various bodily functions.
499
What is one primary function of Vitamin C?
Antioxidant ## Footnote Vitamin C helps to protect cells from damage caused by free radicals.
500
How does Vitamin C minimize cellular damage?
By minimizing free radical damage in cells ## Footnote Free radicals can contribute to various diseases and aging.
501
What health conditions may Vitamin C's antioxidant activity help protect against?
* Heart disease * Cancer * Macular degeneration * Bone loss ## Footnote These conditions are associated with oxidative stress.
502
True or False: Vitamin C contributes to the protection against heart disease.
True ## Footnote Antioxidant properties of Vitamin C may help reduce the risk of heart disease.
503
What is the main function of Vitamin E?
Antioxidant ## Footnote Vitamin E helps to protect cells from damage caused by free radicals.
504
What is the chemical name for Vitamin C?
Ascorbic acid ## Footnote Vitamin C is essential for various bodily functions, including the synthesis of collagen.
505
What role does Vitamin C play in relation to Vitamin E?
Assists in recycling of oxidised vitamin E ## Footnote This function helps maintain the antioxidant properties of Vitamin E.
506
Vitamin C stabilises which form of folate coenzyme?
Reduced form of folate coenzyme ## Footnote This stabilization is important for various metabolic processes.
507
Fill in the blank: Vitamin E is an antioxidant that helps to protect against _______.
Free Radicals
508
True or False: Vitamin C is known to have a role in collagen synthesis.
True
509
What are the two forms of Vitamin E mentioned?
* Alpha Tocopherol * Tocopheraxyi Free Radical
510
What is Vitamin C also known as?
Ascorbic acid ## Footnote Vitamin C is essential for various biological functions.
511
What function does Vitamin C have regarding iron absorption?
Enhances absorption of non-heme iron (from plants) ## Footnote Non-heme iron is found in plant-based foods.
512
List two vital cell compounds that Vitamin C helps synthesize.
* Collagen * Carnitine ## Footnote Collagen is crucial for skin health and carnitine is important for energy production.
513
What is the role of carnitine in the body?
Carries fatty acids from cytosol to mitochondria for energy production ## Footnote Mitochondria are the powerhouse of the cell.
514
Name one hormone that Vitamin C helps in synthesizing.
* Adrenaline ## Footnote Adrenaline is a hormone that prepares the body for 'fight or flight' responses.
515
Fill in the blank: Vitamin C is involved in the synthesis of _______.
Thyroid hormone - thyroxine ## Footnote Thyroxine is critical for regulating metabolism.
516
What are bile acids and how are they related to Vitamin C?
Bile acids are synthesized with the help of Vitamin C ## Footnote Bile acids aid in the digestion and absorption of fats.
517
True or False: Vitamin C is involved in the synthesis of purine bases for DNA synthesis.
True ## Footnote DNA synthesis is essential for cell division and replication.
518
What is the chemical name for Vitamin C?
Ascorbic acid
519
What is one of the primary functions of Vitamin C?
Immune function
520
What impact does regular supplementation of Vitamin C have on the incidence of the common cold?
Does not decrease incidence
521
What is the effect of Vitamin C on the duration of the common cold?
Modest effect on shortening duration
522
What is the impact of Vitamin C on the severity of the common cold?
Reduces severity
523
In which individuals is Vitamin C particularly beneficial?
Individuals exposed to extreme physical stress
524
What does therapeutic supplementation of Vitamin C do for the duration or severity of a cold?
No effect
525
True or False: Regular Vitamin C supplementation decreases the incidence of the common cold.
False
526
Fill in the blank: Vitamin C is known for its role in _______.
[immune function]
527
According to Hemila & Chalker 2013, what type of effect does Vitamin C have on the common cold?
Modest effect on duration and reducing severity
528
What is the chemical name for Vitamin C?
Ascorbic acid
529
What is the absorption efficiency of Vitamin C at usual intakes?
80-95%
530
How does absorption efficiency change with large doses of Vitamin C?
Decreases
531
What gastrointestinal issues can arise from high doses of Vitamin C?
GI discomfort and diarrhoea
532
What percentage of blood ascorbate is found in plasma and erythrocytes?
70%
533
Where is the remainder of Vitamin C found in the body?
White blood cells
534
What forms of Vitamin C are present in the body?
* Mainly ascorbate (ascorbic acid) * 5% dehydroascorbate
535
How is Vitamin C transported into cells?
By glucose transporters
536
Where is Vitamin C stored in the body?
* Leukocytes * Adrenal glands * Pituitary glands
537
Which part of the body contains most of the body's pool of Vitamin C?
Skeletal muscle
538
Is there significant storage of Vitamin C in the body?
Little or no storage
539
What is the RNI for Vitamin C for males aged 19-64 years in the UK?
40 mg/day
540
What is the RNI for Vitamin C for females aged 19-64 years in the UK?
40 mg/day
541
What is the additional Vitamin C requirement during pregnancy?
+10 mg/day
542
What is the additional Vitamin C requirement during lactation?
+30 mg/day
543
What condition does Vitamin C help prevent?
scurvy
544
What are the primary food sources of Vitamin C?
Fruits and vegetables ## Footnote Optimal sources include citrus fruits, strawberries, kiwis, cabbage, spinach, green leafy vegetables, peppers, and tomatoes.
545
Which fruits are particularly rich in Vitamin C?
Citrus fruits, strawberries, kiwis ## Footnote These fruits are known for their high Vitamin C content.
546
Which vegetables are good sources of Vitamin C?
Cabbage, spinach, green leafy vegetables, peppers, tomatoes ## Footnote These vegetables provide significant amounts of Vitamin C.
547
What is the effect of heat and oxygen on Vitamin C?
Highly vulnerable ## Footnote Vitamin C can be degraded by exposure to heat and oxygen.
548
Fill in the blank: Vitamin C is _______ to heat and oxygen.
highly vulnerable
549
True or False: Potatoes are a source of Vitamin C.
True ## Footnote Potatoes contain Vitamin C, but fruits and vegetables are optimal sources.
550
What happens to Vitamin C levels in fresh fruit stored for a long time?
Vitamin C levels decrease due to oxidation. ## Footnote Fresh fruits are more susceptible to losing Vitamin C over time.
551
How does food preparation affect Vitamin C levels in vegetables?
Pre-prepared vegetables have lower Vitamin C levels due to higher surface area exposure. ## Footnote Increased surface area allows for more oxidation and nutrient loss.
552
What are the Vitamin C levels in raw versus cooked cauliflower?
Raw cauliflower has 43 mg/100g, while cooked cauliflower has 27 mg/100g. ## Footnote Cooking leads to a loss of Vitamin C in vegetables.
553
What can affect the Vitamin C levels in stored raw vegetables?
Vitamin C levels can be lower in raw vegetables stored at ambient or chilled temperatures compared to those frozen immediately after harvest. ## Footnote Immediate freezing helps preserve nutrient concentrations.
554
What is the recommended choice for pre-prepared vegetables to retain Vitamin C?
Choose frozen vegetables for better Vitamin C retention. ## Footnote Frozen vegetables retain more nutrients than those stored for long periods.
555
What is the deficiency associated with Vitamin C?
Scurvy ## Footnote Scurvy is a disease resulting from a deficiency of Vitamin C, which is essential for collagen synthesis.
556
Who was the first to present symptoms of Scurvy?
Explorers ## Footnote Symptoms of Scurvy were first noted in explorers during the 14th and 15th centuries.
557
What significant study related to Scurvy was conducted by James Lind?
He discovered that lemons and oranges helped prevent Scurvy ## Footnote James Lind's experiments showed that citrus fruits could prevent Scurvy among sailors.
558
What did scientists label the substance that prevents Scurvy?
Antiscorbutic factor ## Footnote In 1930, scientists identified Vitamin C as the 'antiscorbutic factor'.
559
List three symptoms of Scurvy.
* Skin becomes rough, brown, scaly, dry * Bleeding gums * Delayed wound healing ## Footnote These symptoms are indicative of Vitamin C deficiency.
560
What severe health issue can result from Scurvy?
Sudden death due to massive internal bleeding ## Footnote Severe cases of Scurvy can lead to critical internal bleeding and death.
561
What happens to connective tissues in Scurvy?
They break down due to loss of collagen synthesis ## Footnote Collagen is essential for maintaining the integrity of connective tissues.
562
What percentage of crew members died from Scurvy during major voyages in the past?
Up to 90% ## Footnote High mortality rates from Scurvy were common among sailors in the 14th and 15th centuries.
563
How many sailors did Scurvy reportedly kill between Columbus's voyage and the mid-19th century?
More than two million ## Footnote Scurvy was a significant cause of death during long sea voyages.
564
What is the time frame for the first symptoms of Scurvy to appear after a Vitamin C-free diet?
About 1 month ## Footnote Symptoms can manifest quickly after the absence of Vitamin C in the diet.
565
What psychological effects can result from Vitamin C deficiency?
Depression and irritability ## Footnote Vitamin C is linked to psychological health, and its deficiency can lead to mood changes.
566
Fill in the blank: Scurvy can cause _______ pain and fractures.
Bone ## Footnote Changes in bone mineralization can lead to fractures with minimal trauma.
567
What is a less severe symptom of Vitamin C deficiency compared to Scurvy?
Fatigue and inflammation of gums ## Footnote These symptoms may occur without developing full-blown Scurvy.
568
True or False: Scurvy is common in developed countries.
False ## Footnote Scurvy is rare in developed countries but can occur in individuals with poor diets.
569
What dietary habits may lead to a risk of Scurvy?
Eating very few fruits and vegetables or following extremely restricted diets ## Footnote Poor nutrition is a significant risk factor for Vitamin C deficiency.
570
What physical symptoms indicate changes in bone mineralization due to Scurvy?
Fractures with minimal trauma ## Footnote This is a result of weakened connective tissues and collagen breakdown.
571
What is the fatal dose of Vitamin C?
> 100g/day fatal (but unlikely) ## Footnote High doses are generally not recommended due to potential toxicity.
572
What gastrointestinal issues can high doses of Vitamin C cause?
Diarrhoea and GI discomfort ## Footnote This is due to it being a substrate for bacterial fermentation in the large intestine.
573
Which groups are particularly vulnerable to high doses of Vitamin C?
* Those with haemochromatosis * Those with thalassaemia ## Footnote Vitamin C is linked to increased iron absorption, which can be harmful for these groups.
574
What potential cardiovascular risk is associated with high doses of Vitamin C in diabetics?
Possible increased cardiovascular mortality ## Footnote This suggests a need for caution in diabetic individuals when considering high doses of Vitamin C.
575
What condition has been linked to excess amounts of Vitamin C?
Kidney stone formation in susceptible individuals ## Footnote Excess intake, such as 20xRNI, can lead to this issue.
576
What happens to ascorbate when plasma concentration reaches renal threshold?
Excreted with increasing intake ## Footnote This indicates that excess Vitamin C does not accumulate in the body.
577
What is the role of unabsorbed ascorbate in the intestine?
Substrate for bacterial fermentation ## Footnote This can contribute to gastrointestinal discomfort.
578
What is haemochromatosis?
A genetic disorder with excess iron accumulation in the body ## Footnote It can lead to damage of organs, especially the liver and pancreas.
579
What is thalassaemia?
A hereditary form of anaemia caused by dysfunction in haemoglobin synthesis ## Footnote It is particularly prevalent among certain ethnic communities.
580
What unique effect can Vitamin C have at high doses?
Pro-oxidant effect ## Footnote This is the opposite of its usual antioxidant effect.
581
What is the fatal dose of Vitamin C?
> 100g/day fatal (but unlikely) ## Footnote High doses are generally not recommended due to potential toxicity.
582
What gastrointestinal issues can high doses of Vitamin C cause?
Diarrhoea and GI discomfort ## Footnote This is due to it being a substrate for bacterial fermentation in the large intestine.
583
Which groups are particularly vulnerable to high doses of Vitamin C?
* Those with haemochromatosis * Those with thalassaemia ## Footnote Vitamin C is linked to increased iron absorption, which can be harmful for these groups.
584
What potential cardiovascular risk is associated with high doses of Vitamin C in diabetics?
Possible increased cardiovascular mortality ## Footnote This suggests a need for caution in diabetic individuals when considering high doses of Vitamin C.
585
What condition has been linked to excess amounts of Vitamin C?
Kidney stone formation in susceptible individuals ## Footnote Excess intake, such as 20xRNI, can lead to this issue.
586
What happens to ascorbate when plasma concentration reaches renal threshold?
Excreted with increasing intake ## Footnote This indicates that excess Vitamin C does not accumulate in the body.
587
What is the role of unabsorbed ascorbate in the intestine?
Substrate for bacterial fermentation ## Footnote This can contribute to gastrointestinal discomfort.
588
What is haemochromatosis?
A genetic disorder with excess iron accumulation in the body ## Footnote It can lead to damage of organs, especially the liver and pancreas.
589
What is thalassaemia?
A hereditary form of anaemia caused by dysfunction in haemoglobin synthesis ## Footnote It is particularly prevalent among certain ethnic communities.
590
What unique effect can Vitamin C have at high doses?
Pro-oxidant effect ## Footnote This is the opposite of its usual antioxidant effect.

Nutrition (24 decks)

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