Ch. 13: The Water-Soluble Vitamins
60 mg of tryptophan will produce ___ mg of niacin.
1
Functions of riboflavin include
1. E-yielding metabolism 2. assisting antioxidant rxns
Why are alcoholics more susceptible to Wernicke-Korsakoff syndrome?
1. alcohol increases thiamin excretion in the urine 2. alcoholics consume a diet low in thiamin 3. alcohol decreases thiamin absorption
How are B vitamins present in foods?
1. as vitamins bound to PRO 2. as coenzymes
Why would an average meat-eating person have a low risk for vitamin B12 deficiency?
1. consumption of B12 tends to be 2x the RDA 2. B12 is stored in the liver
Grain products that have been milled are ___ with B vitamins and the mineral iron to lessen the risk of deficiency.
1. enriched 2. fortified
What happens to excess choline in the body?
1. excreted in the urine 2. converted to a related donor of single-C groups
How do we get choline into the body?
1. food intake 2. synthesized by the body
Older adults are at greater risk for pernicious anemia due to
1. lowered production of stomach acid 2. reduced output of intrinsic factor
Taurine functions:
1. photoreceptor activity in the eye 2. platelet aggregation
The coenzyme form of pantothenic acid participates in
1. release of E from CHOs, FATs, and PROs 2. FA synthesis
The functions of vitamin B6 include
1. synthesis of neurotransmitters 2. synthesis of nonessential AAs 3. homocysteine metabolism
A deficiency of riboflavin will appear after ___ of a lack of riboflavin in the diet.
2 months
AI for biotin
30 ug/day for men and women
Enrichment adds ___ back into the food.
4 B vitamins
___ of riboflavin is absorbed via active transport or facilitated diffusion in the small intestine
60 - 65%
B6 plays a major role in
AA metabolism
Do dairy products lower the bioavailability of thiamin?
NO
Does vitamin B6 play a role in the formation of RBC?
NO
Vitamin B6 has NOT been shown in research to help with ___.
PMS
What are functions for all of the water-soluble vitamins?
PRO and AA metabolism E metabolism blood formation and clotting
B12 =
cobalamin
Biotin functions as a ___ for several carboxylase enzymes that add CO2 to various compounds.
coenzyme
Pantothenic acid is part of
coenzyme A
carboxylations =
adding CO2 to compounds
Vitamin C is needed for the production of which protein?
collagen
Coenzymes play an important role in metabolism because they
aid in the function of activating enzymes
Wernicke-Korsakoff syndrome is a thiamin deficiency found in ___.
alcoholics
Which B vitamins participate in E metabolism?
all 8 of them
What is the major fibrous PRO that holds together various structures of the body?
collagen
Vitamin B6 may prevent ___
colon cancer
Neural tube defects that result due to a lack of folate during pregnancy include
anecephaly spina bifida
Vitamin B12 is found naturally in ___ foods only.
animal
Vitamin C may reduce cancer risk due to its ___ properties.
antioxidant
Megadoses of vitamin C
are excreted from the body
Unlike most animals, humans ___ able to synthesize vitamin C.
are not
The RBCs of a folate-deficient person differ from a healthy person by
becoming very large and unable to divide due to the lack of DNA
Rich dietary sources of niacin include
beef fish poultry
A person experiencing weakness, loss of appetite, poor coordination, and edema caused from lack of thiamin is experiencing the deficiency disease known as ___.
beriberi
Raw eggs limit the absorption of
biotin
Which vitamin helps maintain gene stability by binding to the proteins that help DNA fold in the cell nucleus?
biotin
Which enzyme is responsible for the breakdown of biotin?
biotinidase
Signs of scurvy include
bleeding gums slow wound healing
Vitamin B6 ___ be recommended as a treatment for premenstrual syndrome.
cannot
Biotin participates in what type of reaction?
carboxylations
Thiamin is a key component required to release E from the macronutrient
carbs
What transports FAs from the cytosol into the mitochondria?
carnitine
Vitamin-like compounds include
carnitine taurine
Which vitamin deficiency shows no sign of a deficiency disease?
choline
What are good sources of vitamin C?
citrus fruits peppers
Which diets are associated the condition known as pellagra?
corn-based diets
Folate reduces the risk of ___.
developing colon cancer
Pellagra is characterized by
diarrhea dementia dermatitis (and death)
Marginal riboflavin deficiency may occur in people who
do not drink milk
Vitamin C is necessary for the synthesis of ___.
epinephrine thyroxine carnitine
What is true regarding megadoses of vitamin C?
excess vitamin C is excreted from the body
The liver is the main storage site of ___.
fat soluble vitamins
Enriched grain products remain low in
fiber
Enriched grain products remain low in ___.
fiber
What is the most common side effect of a high dose of niacin used to raise levels of HDL-cholesterol?
flushing of the skin
A ___ deficiency leads to megaloblastic anemia.
folate
Folic acid refers to the synthetic form of the B vitamin ___.
folate
Food preparation can destroy 50 - 90% of this B vitamin because it is easily destroyed by heat, oxidation, and ultra violet light.
folate
Name the B vitamin that is required to be added to refined grain products with the aim of preventing neural tube defects.
folate
The coenzymes of which B vitamin are needed for the synthesis and maintenance of new cells?
folate
The water soluble vitamin deficiency that may lead to decreased RBC synthesis and eventually megaloblastic anemia, is due to a lack of the vitamin ___.
folate
Vitamin B12 is required to convert ___ coenzymes to their active forms.
folate
Which B vitamin is key to the formation of the neurotransmitters dopamine and norepinephrine in the brain?
folate
___, a B vitamin, is important in DNA synthesis.
folate
What are some foods that will lower the bioavailability of thiamin?
fresh fish, shellfish coffee, tea blueberries red cabbage, beets, brussel sprouts
The highest folate content may be obtained from eating
fresh fruits and vegetables
Vitamin B6 is responsible for regulation of ___
gene expression
B6 is required for the release of
glucose from glycogen
Food sources high in vitamin C:
green peppers strawberries
High homocysteine levels are a risk factor for
heart attacks AND strokes
B6 converts ___ to the AA ___.
homocysteine cysteine
___ releases riboflavin from its bound forms.
hydrochloric acid
Pantothenic acid is present ___ and supplied by ___.
in all body cells a variety of foods
When either folate or vitamin B12 is lacking, the amount of homocysteine in the body ___.
increases
symptoms of riboflavin deficiency
inflammation of mouth and tongue angular cheillitis dermatitis cracking of tissue around mouth sensitivity to sun confusion
In the US, all bread and cereal products made from milled grains are enriched with which mineral?
iron
Vitamin C enhances the absorption of the mineral ___.
iron
There is no UL set for riboflavin because it
is water soluble and therefore toxic levels cannot be reached
Ariboflavinosis is due to
lack of riboflavin in the diet
Food of animal origin are ___ contributors of choline to the diet.
large
Which foods provide the largest amount of bioavailable folate?
leafy green vegetables legumes liver
Describe a meal rich in thiamin?
lean ham, asparagus, rice, milk
___ thiamin is stored in the body.
little
Side effects of excessive intake of choline include
low BP fishy body odor
How are folate requirements expressed?
mcg as DFE (dietary folate equivalents)
Common food sources for pantothenic acid include
meat mushrooms broccoli milk
main food sources of carnitine
meat and dairy
Food sources of riboflavin include
milk eggs enriched grains
Pantothenic acid storage is
minimal
Where is the main storage site for vitamin B6?
muscle
With dry beriberi, the symptoms are related to the
nervous and muscular systems
Folate is important in the formation of ___.
neurotransmitters
NAD and NADP are coenzyme forms of what B vitamin?
niacin
Pellagra is a _____ deficiency disease.
niacin
Which B vitamin is synthesized from tryptophan?
niacin
Has vitamin C been shown to conclusively prevent heart disease and cancer?
no
Can humans make their own supply of vitamin C? Animals?
no yes
Folate helps to maintain ___.
normal BP
Vitamin B6 helps support ___
normal immune function
Vitamin B6 participates in ___ metabolic reactions.
numerous
Smokers need more vitamin C daily than non-smokers because
of the greater stress placed on the lungs due to the oxidative damage
Pantothenic is derived from the Greek word ___, meaning ___.
pantothen "from every side"
Mushrooms are a good source of which B vitamin?
pantothenic acid
Which water-soluble vitamin is part of coenzyme A, transported bound to RBCs and minimally stored?
pantothenic acid
characteristics of pantothenic acid
part of coenzyme A storage is minimal transported bound to RBCs
The absorption of vitamin B6 is by ___ diffusion.
passive
Thiamin is a coenzyme in the ___ pathway.
pentose phosphate
The risk of riboflavin deficiency increases with long-term use of ___.
phenobarbital
Choline functions as a part of
phospholipids acetylcholine
What term is used to describe when a phosphate group is added to a compound?
phosphorylation
3 food sources rich in thiamin:
pork products legumes sunflower seeds
What are good food sources of vitamin B6?
poultry meat fish
A folate deficiency during pregnancy increases the risk for neural tube defects because folate
promotes the development of the neural tube
In the blood, riboflavin is transported by ___.
protein carriers
Pantothenic acid deficiency is
rare
Ariboflavinosis primarily affects the mouth, skin, and RBCs, causing inflammation of the throat, mouth, and tongue; cracking of the tissue around the mouth, and red, scaly skin is caused by a deficiency of ___.
riboflavin
A deficiency in which vitamins may cause glossitis?
riboflavin niacin vit B6
Long-term use of phenobarbital increases risk of ___
riboflavin deficiency
The deficiency disease for vitamin C is called
scurvy
Where does the absorption of vitamin C occur?
small intestine
Where is thiamin absorbed?
small intestine
Microwaving is similar to ___ in food preparation in terms of retaining the water-soluble vitamins.
steaming
What are the best methods for retaining water-soluble vitamins when preparing food?
stir frying microwaving
Good sources of biotin include
sunflower seeds eggs peanuts liver cauliflower
A riboflavin deficiency usually occurs with a deficiency of several other B vitamins because
these nutrients often occur in the same foods
A deficiency of which vitamin would affect glucose metabolism?
thiamin
Pork, enriched grains, and whole-grain products are excellent sources of ___.
thiamin
There is no UL intake for
thiamin
Wernicke-Korsakoff syndrome is a ___ deficiency.
thiamin
Which vitamin is required for normal functions of the nervous system?
thiamin
What are the B vitamins?
thiamin riboflavin niacin biotin pantothenic acid folate
Choline is absorbed in the small intestine by way of ___ proteins.
transport
T/F: Adults generally get an adequate intake of pantothenic acid.
true
T/F: Generally, almost all niacin that is consumed is absorbed.
true
T/F: Most adults meet the adequate intake for biotin.
true
Where is folate excreted?
urine and feces
What color does riboflavin impart in the urine when consumed in excessive amounts?
yellow
An upper level intake of this B vitamin is set at 100 mg/day, as high intakes can lead to irreversible nerve damage.
B6
What vitamin is used for the synthesis of the neurotransmitters serotonin and dopamine?
B6
Thiamin is a coenzyme required for the metabolism of ___ and ___.
CHOs branched-chain AAs
A high folic acid intake may mask a vitamin ___ deficiency so the FDA limits the amount of this vitamin in nonprescription supplements.
B12
Neurological complications are seen with deficiencies in vitamin ___.
B12
The stomach produces the intrinsic factor that is necessary in order to absorb which vitamin?
B12
Which vitamin deficiency leads to megaloblastic anemia?
B12
Which vitamin has foods of animal origin as its only reliable food source and is the only vitamin that contains a mineral as part of its structure?
B12
Which vitamin is also known as cobalamin?
B12
In what function do all 8 B vitamins participate?
E metabolism
Pantothenic acid is transported bound to
RBCs
Thiamin is transported by
RBCs
The average daily intake for thiamin in men and women is ___ the recommended RDA.
above
The avg daily intake for thiamin in men and women is ___ the recommended RDA.
above
Who is at risk for vitamin B12 deficiency?
vegetarians elderly people w/a malabsorption syndrome
Current research shows that vitamin C has a ___ effect on preventing and treating the common cold.
very modest
Pernicious anemia is related to inadequate ___.
vitamin B12 absorption
Bananas are a rich source of
vitamin B6
Seborrheic dermatitis, microcytic hypochromic anemia, convulsions, depression, and confusion are symptoms of ___ deficiency.
vitamin B6
What vitamin has been used to treat carpal tunnel syndrome and nausea during pregnancy?
vitamin B6
Which B vitamin is important in the synthesis of heme, a nitrogen-containing ring that is inserted into certain PROs to hold iron in place?
vitamin B6
High does of this vitamin slightly increase the risk of kidney stones and iron-absorption disorders.
vitamin C
The category of vitamins that need to be replaced daily are the ___.
water-soluble vitamins
Megadoses of vitamin C ___ be toxic.
will not
