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DEMS exam 2 part 2 > water soluble vitamins > Flashcards

water soluble vitamins Flashcards

1
Q

what are the functions of thiamin (Vitamin B1)

A

Thiamine Diphosphate (TDP or thiamin pyrophosphate TPP): coenzyme central to intermediary metabolism in all cells, esp. glycolysis, TCA cycle, amino acid metabolism; decarboxylation; transketolation reactions; TTP thought to bind at Na+ channel in nerve membranes; many function in nerve conduction

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2
Q

what are the rich Food sources for Thiamin (B1)

A

whole grains (high in germ), enriched grains, lean pork, legumes

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3
Q

whar are the Requirements/intake recommendations for thiamin (B1) :

A

RDA: 1.1-1.2 mg/d.

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4
Q

what is the Treatment for Thiamine deficiency:

A

50-100 mg intramuscular or intravenous.

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5
Q

deficiency in Thiamin can cause:

A

Beriberi (3 types)

1) dry (paralytic/nervous) beri beri
2) wet (cardiac) Beri Beri
3) Wernicke-Korsakoff syndrome (cerebral beriberi)

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6
Q

what are the symptoms of Dry (paralytic/nervous) beriberi:

A

peripheral neuropathy w/ impairment of sensory, motor, and reflex functions; affects distal > proximal limbs; muscle tenderness, weakness/ atrophy, foot/wrist drop

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7
Q

what are the Sx’s Wet (cardiac) beriberi

A

edema and high output cardiac failure (tachycardia, cardiomegaly and CHF) + signs/sxs of dry beriberi

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8
Q

what are the Sx’s of Wernicke-Korsakoff syndrome (cerebral beriberi):

A

“Triad”

1) ocular signs (nystagmus, ophthalmoplegia),
2) ataxia (lack of muscle control or coordination of voluntary movements),
3) amnesia/mental confusion

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9
Q

what are the biochemical evaluations for Thiamine deficiency?

A

Erythrocyte transketolase activity; blood thiamine levels

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10
Q

which populations are at risk for thiamine deficiency

A

Alcoholics most at risk in US (low intake, poor intestinal absorption, defective metabolism);
Elderly: relatively high incidence of mild deficiency; Chronic renal dialysis patients;
adults on high carbohydrate diet, ;
Refeeding after starvation
Bariatric surgery (assoc. w/ bypass, banding, and gastric sleeve).

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11
Q

what are the Functions of RIBOFLAVIN (B2):

A

Part of 2 co-enzymes, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) which function in oxidation/reduction reactions in TCA cycle and oxidative phosphorylation. Amino acid & fatty acid metabolism; metabolism of vit K, folate B6, niacin.

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12
Q

what are the richest food sources of RIBOFLAVIN (B2)

A

liver, wheat germ;

Dairy = largest contribution to intake in US diet (UV light destroys the vitamin), meats & poultry; leafy greens

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13
Q

what are the Deficiency signs of Riboflavin (B2):

A

oral-ocular-genital syndrome -
cheilosis (cracked lips),
angular stomatitis (sores at corner of mouth),
increased vascularization of conjunctiva and photophobia,
seborrheic dermatitis and scrotal dermatitis.

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14
Q

water soluble vitamins are Generally not “stored” in body except for _____ .

A

B12

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15
Q

Breast milk reflects maternal intake/status of water soluble vitamins except _____

A

folate

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16
Q

what are the functions of NIACIN (B3)

A

Nicotinamide is substituent of the electron carrying substances NAD & NADP

17
Q

what are the Food sources for niacin

A

Meats, poultry, fish, peanut butter, legumes are major sources of preformed niacin. Tryptophan = precursor; diets w/ liberal amounts of milk and eggs (rich in tryptophan) are likely adequate for niacin, even if low in preformed niacin.

18
Q

what are the symptoms of Niacin deficiency

A

Dermatitis: characteristic symmetric pattern, scaling w/ areas depigmentation & hyperpigmentation, aggravated by sun, heat exposure
Dementia: confusion, dizziness, and hallucinations
Diarrhea
Death

19
Q

In Niacin (B3) Deficiency, what are the Predisposing Factors

A

1) Nutritional/dietary restriction Cornmeal (w/o germ) based diet (esp w/o alkaline/lime treatment)

2) Malabsorption syndromes
3) Alcoholism
4) Metabolic “shunting” (ie. carcinoid tumor w/ ↑ serotonin -> decreased tryptophan

20
Q

which vitamins are the hematopoietic vitamins

A

Folate and B12

21
Q

what are the functions of folic acid?

A

single C transfers
nucleic acid synthesis
amino acid metabolism
DNA Methylation – regulation of gene expression / epigenetics

22
Q

what are the food sources of folate

A

“foliage,” deep green veg
orange juice
whole grains

23
Q

who are at risk for folate deficiency

A

Inadequate intake or increased destruction in food
Alcoholics
Pregnancy

24
Q

what are the signs and sx’s of folate deficiency?

A 
Macrocytic anemia
*Hypersegmented neutrophils
*Glossitis, irritability
*Homocysteinemia
 Neural tube defects (occurrence/recurrence
25
Q

Women of child bearing age advised to have intake of ____ to prevent neural tube defects

A

400-800 micro grams/day*

26
Q

what are the functions of Vitamin B12 (cobalmin)

A

Reform tetrahydrafolate from methylfolate (synthesis of methionine)
Catabolism of odd chain length fatty acids
Catalyze isomerization of methylmalonyl Co-A  succinyl Co-A (lipid & CHO metabolism)

27
Q

Vitamin B12 that is Transported in circulation is called ____

A

Transcobalamin II

28
Q

Vitamin B12 has large _____ stores and is primarly excreted via _____

A

liver,

bile

29
Q

What are the risk factors for B12 deficiency?

A

Inadequate IF secretion or antibodies to IF
Gastric atrophy/gastrectomy
Ileal resection
Breastfed infant of B12 deficient vegan mother

30
Q

what are the effects of B12 deficiency?

A

Macrocytic anemia & hypersegmented neutrophils

Neurologic disturbances: depression, paresthesias, gait disturbances, burning tongue, dizziness

31
Q

What are the 6 Functions & Physiologic Roles of Vitamin C (Ascorbic Acid)

A

1) Reversible antioxidant, Vitamin E sparing
2) Provides reducing equivalents to enzymes:
Reduction of iron so increases absorption
3) Conversion dopamine to norepinephrine
4) Leukocyte function ( Increased [AA] wbc)
5) Co-substrate inCollagen synthesis: hydroxylation of proline & lysine; cross-links for tropocollagen
6) Hydroxylation of tryptophan to serotonin

32
Q

what are the sx’s of Vit C deficiency (scurvy)

A

1) Hemorrhagic signs (Bleeding gums, ecchymoses, petechiae)
2) Hyperkeratosis of hair follicles + perifollicular hemorrhages
3) Hypochondriasis: depression, weakness
4) Hematologic abnormalities
Anemia: iron &/or folate deficiencies, bleeding

33
Q

what is the progression of scurvy

A

weakness, aching joints/bones/muscles, hemorrhagic signs

34
Q

Benefits of “megadoses” Vitamin C ?

A

may reduce duration of cold sx’s

good for wound healing

DEMS exam 2 part 2 (17 decks)

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