Water-Soluble Vitamins Flashcards
1
Q
Both water and fat- soluble vitamins have the following factors in common:
A
- organic, essential nutrients required in small amounts
- molecules of vitamins are individual units
- methods of food preparation can degrade vitamins
- some vitamins have more than one chemical structure with differing biological potency or different functions.
2
Q
The following water-soluble vitamins have an AI and not a RDA.
A
- Biotin
- panthothenic acid
- vitamin k
- vitamin d
- choline
3
Q
Name the B vitamins
A
-thiamin
- riboflavin
-niacin
- biotin
- pantothenic acid
- vitamin B6
-folate
-vitamin B12
-vitamin C
(ALL OF THESE VITAMINS ACT AS COENZYMES EXCEPT FOR VITAMIN C)
4
Q
Thiamin’s coenzyme name and function
A
- thiamin pyrophosphate (TTP)
- FACILITATES ENERGY METABOLISM
5
Q
Riboflavin’s coenzyme name and function
A
- Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN)
- facilitates energy metabolism
6
Q
Niacin’s coenzyme name and function
A
- Nicotinamide adenine dinucleotide (NAD) and (NADP)
- facilitates energy metabolism
7
Q
Biotin’s coenzyme name and function
A
- Biotin
- facilitates energy metabolism
8
Q
Pantothenic Acid’s coenzyme name and function
A
- Coenzyme A
- facilitates energy metabolism
9
Q
Vitamin B6 (pyridoxine)’s coenzyme name and function
A
- pyridoxal phosphate (PLP)
- facilitates energy metabolism and amino acid metabolism
10
Q
Folate’s coenzyme name and function
A
- folate coenzymes (in the tetrahydrofolate forms)
- transfers one-carbon units called methyl groups
11
Q
Vitamin B12 (cobalamin)’s coenzyme name and function
A
- Vitamin B12
- removes methyl group to activate folate and myelin formation
12
Q
Function of Vitamin C (ascorbic acid)
A
water-soluble antioxidant
13
Q
Coenzyme
A
- a vitamin or provitamin plus a molecular structure that assists in the catalytic actions of enzymes.
- some enzymes need coenzymes and some do not
14
Q
The workings of a coenzyme
A
- Coenzyme binds with enzyme on its’ active site and becomes an activated enzyme
- Two substrates can bind
- The substrates leave as a new product together
- Enzyme and Coenzyme are recycled
15
Q
What two steps of energy metabolism is thiamin as the coenzyme (TPP) responsible for?
A
- converts pryuvate to acetyl CoA
2. removes C from a 5C compound in the TCA cycle.
16
Q
True or False
Thiamin is involved in nerve and muscle processes.
A
TRUE
17
Q
In the United States, ________ deficiency is observed most often in alcoholics, called Wernicke-Korsakoff syndrome.
A
thiamin
18
Q
Ethanol decreases the absorption and increases the excretion of _______. Symptoms of ________ syndrome include disorientation, lose of short term memory, jerky eye movements, and staggering gait.
A
- thiamin
2. Wernicke-Korsakoff syndrome
19
Q
Thiamin deficiency can result in the disease ________; symptoms include weakness, nerve damage, muscle wasting, change in cardiovascular system, and occasionally edema.
A
beriberi
20
Q
______ is an excellent natural source of thiamin and small amounts of thiamin are found in all ______ ______.
A
- Pork
2. food groups
21
Q
Riboflavin has two coenzyme forms (FMN and FAD). They both accept and then donate ________. FAD picks up _____ and their _____ in the TCA cycle and delivers them to the _______ _____ ____ where 2 ATP are produced.
A
- two H+ ions
- two H+ ions
- electrons
- electron transport chain
22
Q
Name 2 good sources of Riboflavin.
A
- milk
- whole grain and enriched grain products
23
Q
True or False
Riboflavin is stable when exposed to ultraviolet light and irradiation but destroyed when heated.
A
FALSE
Riboflavin is stable when heated but destroyed when exposed to ultraviolet light and irradiation.
24
Q
Riboflavin deficiency does not exist in the U.S. due to _____________.
A
fortification of grain foods.
25
Niacin is also known as _________ or _______.
1. nicotinic acid
| 2. nicotinamide
26
Niacin has two coenzymes: _____ and _____. They are both directly involved in energy metabolism and ________.
1. NAD
2. NADP
3. oxidation-reduction reactions
27
NAD pick up a ___ in _____ and several places in the TCA cycle and carries it to the __________ where each NADH produces 3 ATP.
1. H+
2. glycolysis
3. electron transport chain
28
Niacin can be obtained directly from foods and can be synthesized in human cells from the amino acid _______.
tryptophan
29
The conversion of tryptophan to niacin requires the coenzymes of ______,______ and ______. One needs to eat ____ mg of tryptophan in order to produce 1 mg niacin.
1. riboflavin, thiamin, and vitamin B6
| 2. 60 mg
30
Recommended intakes of niacin are stated as _________. One ____ equals 1mg of niacin.
1. Niacin equivalents (NE)
| 2. NE
31
Pellagra is a disease that occurs when individuals consume inadequate amounts of ______ and have a diet very low in _______.
1. niacin
| 2. tryptohpan
32
Pellagra was in epidemic proportions in the U.S. in the early ____ when populations in low socioeconomic groups in the South consumed most of their energy from ____ products.
1. 1900's
| 2. corn
33
4 D's of Pellagra
1. Diarrhea
2. Dermatitis
3. Dementia
4. Death (sometimes)
34
In 1938 the U.S. mandated fortification of processed grains such as flour and rice with ____, _______, and ______. _______ was eradicated as a result of this very effective public health initiative.
1. niacin
2. thiamin
3. riboflavin
4. Pellagra
35
TRUE OR FALSE
| There is no risk of niacin deficiency.
TRUE
36
Pharmacological doses of niacin in the dorm of nicotinic acid have been prescribed to help _______ _____ ______.
1. lower blood cholesterol
37
The RDI committee established the UL of nicotinic acid at ___mg/day (for supplement of nicotnic acid) compared to the RDA of __-___mg/day.
1. 35 mg/day
| 2. 14-16 mg/day
38
Biotin is needed in very small amount, but is critical in the...
1. TCA cycle (coenzyme for enzyme that generates oxaloacetate from pyruvate)
2. gluconeogenesis
3. fatty acid synthesis
4. breakdown of some fatty acids and amino acids
39
TRUE OR FALSE
| Biotin is widepsread in foods and can be synthesized by bacteria in the GI tract.
TRUE
40
TRUE OR FALSE
| Pantothenic Acid is not abundant in dietary sources/
FALSE
41
Pantothenic Acid is a part of _______, the crossroads of the energy pathway, producing acetyl CoA.
coenzyme A
42
Name the three major chemical forms of B6
1. pyridoxine
2. pyridoxal
3. pyridoxamine
43
The coenzyme of B6, pyridoxylphosphate (PLP), is important in the following:
1. metabolism of amino acids
2. production of hemoglobin (carries oxygen in blood)
3. conversion of tryptophan to niacin
4. efficient function of nervous system (B6 converted to serotonin and dopamine)hr carbon part of the molcule for energy metabolism.
5. functioning of immune system
6. transfer of amine groups (-NH2), this PLP assists enzymes which cleave of the amine group on some amino acids making available t
44
The effects of vitamin B6 deficiency include:
- dermatitis
- glossititis (smooth, sore tongue)
- depression
- confusion
- convulsions
45
What is the UL and the RDA for vitamin B6
UL: 100 mg/d
RDA: 1.3 mg/day
46
Folic Acid
- is the synthetic form of folate used in supplements and fortified foods.
- its structure is more simpler and is more easily adsorbed by the body.
- after absorption the two forms are identical
47
Because of the differences in bioavailability of folate and folic acid, folate is measure in dietary folate equivalents (DFE).
1ug food folate =___DFE
1ug folic acid= ____ DFE
1. 1 DFE
| 2. 1.7 DFE
48
Digestion and Absorption of Folate and Folic Acid
1. a. Folate in the polyglutamate form is broken down into monoglutamate
b. Folic Acid is all ready in this form
2. In small intestine, methyl group is attached and folate is absorbed
3. In blood, folate circulates in the monoglutamate-methyl group form to be delivered to cells
4. Excess folate-->liver-->secreted w/ bile--> SI-->can be reabsorbed if needed (enterohepatic circulation)
49
TRUE OR FALSE
| B12 deficiency can cause folate deficiency
TRUE
50
Folate is involved in reactions that require the transfer of _________ (i.e., CH3 called methyl groups). The transfer of a methyl group from folate to _______ activates both the ______ coenzyme and _______ coenzyme.
1. one carbon
2. vitamin 12
3. folate
4. vitamin B12
51
After folate enters the cells, vitamin B12 binds with methyl group. Now both vitamin B12 and folate are....
ready to facilitate reactions as coyenzymes
52
TRUE OR FALSE
| Folate is necessary for the production and maintenance of new cells and to make DNA and RNA.
TRUE
53
Folate and/or B12 deficiency can result to:
megalbolastic anemia- decrease in DNA synthesis, thus impairing cell division. The large immature red blood cells are unable to divide and cannot efficiently transport oxygen.
54
In ______, the Food and Drug Administration mandated the fortification of processed grains such as flour and rice with folic acid.
1998
55
Pregnant women who consume larger amounts of folic acid can prevent ______ and ______.
1. neural tube defects
| 2. spina bifida (most prevalent)
56
Spina Bifida
-caused by incomplete closure of the fetal neural tube atr about 28-30 days after conception
57
TRUE OR FALSE
Folic acid fortification was controversial at first because high folic acid can mask a vitamin B12 deficiency; which can lead to irreversible nerve damage.
TRUE
58
A UL for folic acid has been set at ________ micrograms/day to prevent masking of B12 deficiency.
1,000 micrograms/day
59
Homocysteine
- amino acid degradation product usually found in only minute amounts of blood
- found to be elevated in heart disease
60
TRUE OR FALSE
| Folate, as well as other vatamins (B6 and B12) are important in the degradation of homocysteine.
TRUE
| however research shows that is does not reduce the risk of heart disease
61
Vitamin B12 is a large, organic molecule containing _______ hence, the scientific name of cobalamin.
cobalt (Co)
62
Vitamine B12 has another unique role as a coenzyme for an enzyme in the production of nerve tissue ________.
myelin
63
Digestion and Absorption of Vitamin B12
1. In food vitamin B12 is bound to a protein
2. IN stomach, HCl & pepsin releases B12 from the protein
3. B12 combines with intrinsic factor (IF) before being absorbed in the blood stream from SI
4. Vitamin B12 is recycled through the enterophepatic ciruculation (stored in liver)
64
TRUE OR FALSE
| There is only a small amount of B12 stored in the liver, so it is very easily depleted.
FALSE
| B12 is stored in the liver, so much so, that it usually takes years for an adult to deplete vitamine B12.
65
Vitamin B12 is naturally found in _______ foods but now if found in fortified ______ and _______.
1. animal foods
| 2. breakfast cereals and soy products
66
TRUE OR FALSE
| Unlike most water-soluble vitamins, microwave cooking can destroy vitamin B12. (but stove top does not)
TRUE
67
Who should worry about B12 deficiency?
People with vegan diets and older adults (<50)
68
Vitamin B12 deficiency is called _________ because of the two symptoms that develop ________ due to folate depletion and _______ because of poor myelin formation.
1. pernicious anemia
2. megaloblastic anemia
3. neurological problems
69
Older adults are at risk for pernicious anemia because of _______ ______, caused by the reduction of HCL and IF and resulting in poor absorption of vitamin B12 causing impaired functioning of the tissue lining the stomach.
atrophic gastritis
70
Vitamin C deficiency can cause ______.
scurvy
71
TRUE OR FALSE
Vitamin C is hardly ever destroyed by exposure in neutral and alkaline environments to oxygen, light, heat, and metallic surfaces.
FALSE
72
Storing fresh vegetables at room temperature for a few days significantly lowers the ________ content.
Vitamin C
73
Vitamin C has an important role as an _______, helping protect the body from free radical damage and reducing oxidative stress.
antioxidant
74
Symptoms of milkd vitamin C deficiency include:
- bleeding gums
- lack of energy
- weakness
- increased susceptibility of infection
- dull aching pain in muscles and joints
75
As vitamin C deficiency progresses to scurvy, the symptoms observed reflect the role of vitamin C in ________ formation.
collagen
76
Vitamin C helps iron serves as a cofactor in the ________ of ______ to hydroxproline. This step has the effect of cementing the protein matrix of collagen. Without Vitamin C and iron, the collagen is _______.
1. hydroxylation of proline
| 2. weak
77
When Vitamin C deficiency leads to weak collagen it results in:
- blood vessels rupturing leading to pinpoint hemorrhages
- bruising
- slow wound healing
- bleeding gums
- loose teeth
- skin develops rough dry surface around hair
- abnormal bone formation leading to calcification of some soft tissues, decreased bone density, swollen, painful joints.
- anemia may be present
78
____ mg/d of Vitamin C can prevent scurvy.
10
79
Needs for Vitamin C increase for individuals who:
- smoke
- suffer from chronic illnesses or frequent infections
- have added physical stress
- alcoholics
80
________ is the only vitamin that has a separate RDA for smokers.
Vitamin C
81
Smoker RDA for Vitamin C ____ mg/day
| Adult RDA for Vitamin C ____ mg/day
smoker- +35 mg/day
| adult- 75-90 mg/day
82
The UL for vitamin C is ____ mg/day
2,000
83
Choline
- is a conditionally essential vitamin
- has an AI
- can be made in the body from amino acid, methionine
- found in many foods which contain lecithin such as eggs and milk
- needed to make the neurotransmitter acetylcholine
84
Inositol and Carnitine
- still under consideration of vitamin status
- no AI established
- can be made in body
- widespread in foods
85
Which of the following have had NO reports of toxicity symptoms?
a. riboflavin and niacin
b. thiamin and cobalamin
c. vitamin C and vitamin B6
d. niacin and folate
B. thiamin and cobalamin
86
A deicinecy of which vitamins can result in accumulation of homocystein in the blood?
folate and vitamin B12
87
The appearance of neurological symptoms of pernicious anemia bay be delayed due to high intake of supplements of ______.
folate
88
You are a dietitian and see the report of the blood work from a woman in her 20's who is pregnant. Her red blood cells are larger than normal, so you suspect that her diet is low in _______.
folate
89
Which of the following diet is most likely to lead to beriberi, a deficiency seen in poor countries but rarely in the U.S.?
a. high intakes of white, refined rice
b. high intake of corn based foods without lime treatment
c. high intakes of unrefined rice
d. low intakes of food grown near the ocean
A. high intakes of white, refined rice
90
A general niacin deficiency is known to be manifested in abnormalities of all of the following organs/systems except what?
a. gastrointestinal tract
b. nervous system
c. skeletal
d. skin
c. skeletal
91
One of the water-soluble vitamin has been in many claims in magazines that it will improve a brain neurotransmitter, and thus may help such conditions as premenstrual syndrome (PMS). Unfortunately, double-blind controlled studies do not confirm these claims. This vitamin is _____.
pyridoxine
92
Name the vitamins that are found in foods across most food groups and this deficiency is extremely rare.
vitamin B6 and pantothenic acid
93
General characteristics of most of the water-soluble vitamins
- toxic levels in the body are rarely found, but possible with supplements
- they are absorbed directly into the blood
- excesses are eliminated through kidney function
