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54 Cards in this Set

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What is the RDA for Niacin (Vit B3)
14 mg, 16 mg
Main coenzyme for pantothenic acid?
Coenzyme A (CoA)
Niacin deficiency
pellegra
pantothenic acid function
acyl transfer reactions
biotin functions
co2 transfer and carboxylation rxns
vit B6 main coenzyme
PLP (pyridoxal phosphate)
Vit B6 functions
transamination and decarboxylation rxns, decreases blood homocysteine
Vit B6 RDA
1.3 mg
folic acid main coenzyme
derivatives of tetrahrdrofolic acid (THF)
folic acid functions
one-carbon transfer rxns, purine and pyramidine synthesis (cell replication), and lowers blood homocysteine
folic acid deficiency
megaloblastic anemia
Vit B12 main coenzymes
methly cobalamin, adenosyl cobalamin (cobalamides)
Vit B12 functions
1. methylation of homocysteine to methionine (a.a. metabolism-activation of folic acid. lowers blood homocysteine, methylcobalamin is produced)

2. conversion of methylmalonyl CoA to succinyl CoA (f.a. metabolism-involves proprionic acid breakdown, used for B12, BCH assessment)
Vit B12 deficiency
megaloblastic anemia, degeneration of peripheral nerves
Vit B12 RDA
2.4 micrograms
Vit C reduced name
Ascorbic Acid
Vit C oxidized name
dehydro-C
Vit C functions
1. antioxidant-over UL, could be a pro-oxidant
2. hydroxylating (adding an -OH group)
3. collagen (connective tissue)
4. carnitine (long chain f.a. uptake into mitochondria)
5. norepinephrine (vit C works on dopamine to form this)
6. Vit C increases the inorganic iron absorption
Vit C deficiency
scurvy
Vit C RDA
75 mg, 90 mg
Riboflavin coenzymes
FAD (flavin adenine dinucleotide), FMN (flavin mononucleotide)
Riboflavin deficiency
cheilosis
Three main forms in food of Vit B12
adenosylcobalamin, hydroxocobalamin, methlycobalamin
Corrinoids are associated with
Vit B12
cobalt is found in the structure of which vitamin?
Vit B12
Vit B12 recommendations for adults 50 years and over?
6-300 micrograms
In nature Vit B12 is found in?
microbes in soil (main environmental source), water, and the rumen or ileum.
In foods Vit B12 is found in?
foods of animal origin (meats, fish, egg yolk, dairy products)
Vit B12 is fortified in what?
cereals and soy products
Vit B12 is found in what fermented food?
tempeh which is fermented soybean
What grown on a B12 medium can serve as a B12 source?
nutritional yeast
Important B12 sources in developing countries include?
contaminated drinking water, poor dental hygiene, insect contaminated food, and microbes that enter the mouth from dirty hands.
Supplemental forms of Vit B12
cyanocobalamin (BEST), hydroxocobalamin, and methlycobalamin
Vit B12 supplements are administered by:
pill, injection (after stomach or ileum surgery), sublingual spray (not necessary)
Food B12 can be destroyed by:
acid, alkali, light and redox agents
Is supplemental B12 a protein complex?
No
Newly abosorbed B12 will be transported in blood bound to?
transcobalamin II (TCII)
At the illeal receptor for B12 what nutrient is needed?
calcium
What percent of B12 can be absorbed by diffusion with no IF?
1-3%
What are the two causes of megaloblastic anemia for B12?
primary deficiency-poor intake, secondary deficiency-poor absorption
Why might deficiency for B12 take several years to develop?
large body stores and enteroheaptic reabsorption
What are some deficiency signs of Vit B12?
glossitis (loss of tongue papillae), GI tract damage, hypersegmented polymorphonuclear leucocytes (segmented chromatin-definitive for B12/folate), macroovalocytes (elliptical RBC)
Deficiency of B12 may be seen in
1. Vegans
2. Stomach surgery/disease (decrease IF, acid, pepsin, "R" factor)
3. Ileal surgery/Disease (decrease receptors for B12 absorption)
4. Parasitism (parasites use B12-compete with humans for it)
5. Achlorhydria (decrease acid-drugs, aging, surgery)
6. Alcoholism (stomach damage)
7. Elderly
8. Individuals lacking IF (pernicious anemia)-autoimmune disease
In B12 deficiency what increases in urine
methylmalonic acid because it doesn't get converted to succinyl CoA
What is also called pteroylglutamate, pteroylmonoglutamate, or pteroylmonoglutamic acid
folate
What is a reduced, active form of folate?
tetrahydrofolate polyglutamate molecules (protected by Vit C)
Purine/Pyrimidine synthesis is essential for what?
cell division, protection and repair of DNA
1. Fetal development
2. GI tract cell formation
3. Red and White blood cell formation
A.A. metabolism in folate is responsible for
1. Glycine conversion to serine and serine conversion to glycine
2. homocysteine converted to methionine
3. histidine conversion to glutamate (folacin, B12 assessment!)
On folate, single carbon transfer takes place on where?
N-5, N-10
How many additional glutamic acid molecules can be added to the acid component of folic acid?
3-9 and they are called polyglutamates which are common in food
pteridine is what part of folic acid
nucleus
what drugs can decrease B12 absorption
1. antacids
2. hydrogen blockers, like pepcid AC (OTC)
3. proton pump blockers, like Nexium and Protonix (prescription)
To lower homocysteine levels what amounts of folic acid, B6, and B12 have been recommended?
1. Folic acid-at least 1000mcg-up to 2500mcg (UL-1000mcg)
2. B6-at least 10mg up to 25mg (UL-100mg)
3. B12-at least 400mcg up to 1000mcg (UL-none)
controlling homocysteine may lower risk for what?
1. CVD
2. Alzheimer's disease
3. Hypertension
4. Stroke
5. Diabetes complications (retinopathy, neuropathy)