Micronutrients II - Vitamins Flashcards by Angela Mitchell

What is the function of vitamins?

cofactors for enzymes

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How many essential vitamins?

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What are vitamins typically used for?

cofactors for enzymes
(not catabolized to CO2 and H2O like macronutrients)
(organic)

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What type of vitamins cause problems in excess?

lipid soluble

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List the 4 lipid soluble vitamins.

Vit A, D, E, K

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List the 9 water soluble vitamins.

thiamin
Riboflavin (B2)
Niacin (B3)
Pantothenic Acid (B5)
Pyridoxine B6
Biotin
Folate
Vitamin B12
Vitamin C

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There is only one role of vitamins. (T/F)

False. One vitamin can have many roles.

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What are some vitamin-like compounds?

inositol (phospholipids)
choline
lipoic acid (required for pyruvate ….
PQQ (pyrrologuinoline quinone

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What is thiamine used for?

Coenzyme
energy metabolism
DNA/RNA synthesis

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How are fat soluble vitamins absorbed?

small intestines

with dietary fat
digestive enzymes from pancreas help

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How are fat soluble vitamins transported and stored?

transported by specific binding proteins
liver
lipoproteins/fat droplets

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What are the specific differences between Vit A, D, E, K?

Source
A - animal and plant
D - fish , mushroom, milk
E - plants
K - plants
Function
A - growth, reproduction, vision
D- calcium homeo, bone, cell differentiation
E- antioxidant, cell membrane, eye, heart
K- coenzymem, blood clotting, bone, tooth

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What family of molecules make up vitamin A?

mixture of retinoids

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What is the importance of Vitamin A?

gene regulation, neuronal signaling

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What happens with excess vitamin A?

birth defects (teratogenic), blurred vision, liver damage

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How should your source of vitamin A come from?

dietary b-carotene safer source

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What can carry Vitamin A in the blood?

albumin

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What is vitamin A required for in the eye? consequence

physical structure of eye; xerophthalmia

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What consequences for Accutane?

birth defects; drug can stay in systems for month

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What the Vitamin A RDA for men? women?

Men - 900 ug/day

Women - 700 ug/day

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Vitamin A deficiency is a world-wide problem. How many preschool children are blinded

250,000 - 500,000

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What does deficiency of Vitamin D lead to?

Rickets (children)

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How is Vitamin D derived?

synthesized in skin when UV light is present

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What is the synthesis process of Vitamin D? end product?

calcitrol

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What is the group of related lipids involved in control of Ca2+?

D3 | 1,25-dihyroxycholecalciferol

What vitamin seems to be a general deficiency in the U.S. population?

Vitamin D

What does excess vitamin D lead to?

local tissue toxification due to calcification in tissue

There is a link between vitamin D deficiency to which diseases?

diabetes, autoimmune disease, cardiovascular, cancer

What group of molecules make up vitamin K?

phylloquinones; K1 - green leafy vegetables K2 - menaquinone - made by bacteria in intestines K3 - menadione -artificial, made commercially

What inhibits vitamin K?

coumarin/warfarin (discovered due to cattle eating sweet clover hay and hemorrhaging)

What does coumarin inhibit specifically?

vitamin K epoxide reductase

What is the importance of thiamine?

helps form and break C-C bonds; heavily involved in carbohydrate metabolism

What is thiamine deficiency?

Beriberi disease;

What results from Beriberi disease?

insufficient ATP production, muscle wasting, CNS damage, edema

In whom is Beriberi disease seen?

sailors | alcoholics

What is the RDA for thiamine?

1.2 mg/day

What is Wernicke syndrome?

thiamine deficiency; associated with chronic alcoholism

Korsakoff encephalopathy

severed thiamine deficiency involving CNS | Wernicke already in place so Wernicke-Korsakoff -WK- irreversible short term memory loss

What is the function of Riboflavin?

used for electron transfer, | usually cofactors of enzymes, oxygenases, oxidoreductase

Clinically what do you see in riboflavin deficiency?

glossitis, cracking of tissues are the lips (cheilossis) | normacytic anemia

Riboflavis is heat stable but ____ sensitive.

light

What is niacin used for?

nicotinic acid is precursor for NAD

What does deficiency in niacin show physically?

pellagra (Casal's necklace) | often on back of neck

What is the RDA for niacin? | quantified as niacin equivalents (NE)

Men - 16 mg NE/day | Women - 14 mg NE/day

What clinical symptoms do you see in niacin deficiency?

fatique, headache, apathy, depression, memory loss, dementia

Excess niacin causes what symptoms?

flushin, burning of face, arms, chest | stomach irritation

How does niacin lower cholesterol?

activates G-protein coupled receptor

What is the function of pantothenic acid?

carry acyl chains

Hard to differentiate Pantothenic deficiency from other B vitamins. What are some?

burning feet

What family of compounds comprise Pyridoxine?

pyridozal phosphate,.....

What deficiency is seen in Pyridoxine?

dermatitis

What is RDA for pyridoxine?

1.3 mg/day

What symptoms in deficiency of pyridoxine?

seizures, confusion

What drugs can bind to pyridoxal and create deficiency?

penicillinamin, isozianid (treatment of cystinuris, RA)

What is estimated RDA for biotin?

30 ug/day

What synthesizes biotin?

gut bacteria

What is the function of biotin?

carboxylase reactions in fatty acid synthesis, lipid metabolism

What is seen in biotin deficiency?

impaired glucose tolerance, mental dysfunction, anorexia, dermatitis

What is the unique feature of cyanocobalamin?

metal component

How is cyanocobalamin synthesized?

bacteria

What is the RDA for cyanocobalamin?

3 ug/day

What enzymatic reactions is cyanocobalamin involved?

intramolecular rearrangements ribonucleotide reductrace methyl group transfers (methionine synthesis from homocysteine>

What results in cyanocobalamin deficiency?

intimate interaction with folate; anemias

What is pernicious anemia?

megaloblastic anemia due to lack of intrinsic factor secretion; increases with aging population

What can a B12 (cyanocobalamin) deficiency lead to?

elevated homocysteine levels which are linked to cardiovascular disease due to interference with collagen maturation

What does Metformin impair?

uptake of B12

What is plasma level to show deficiency in B12?

<148 pmol/L

What is homocystein?

removed methyl from methionine

What does elevated homocystein indicate?

low B6, B12 or THF

What is the only way to absorb B12?

IF (intrinsic factor)

What is folate vital for?

DNA synthesis

What is RDA for Folate?

3 ug/day

Single carbon transfers require?

folate | Vitamin B12

Folate deficiencies result in what type of embryologic problem?

neural tube defects

What is megablastic anemia?

caused by folate and cobalmin deficiencies | enlarge RBC