Water soluble Vitamins Flashcards

1
Q

Does chronic intake alter tissue levels?

A

yes

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2
Q

Toxicity?

A

usually low

B6 = exception

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3
Q

Absorption

A

usually high

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4
Q

Breast milk reflective of maternal status?

A

yes, except folate?

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5
Q

Excretion

A

via urine

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6
Q

Energy releasing

A

Thiamine
Riboflavin
Niacin

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7
Q

Hematopoietic

A

folic acid

B12

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8
Q

Non B complex

A

ascorbic acid vitC

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9
Q

Thiamine
Riboflavin
Niacin

function

A

all involved in glycolysis / TCA

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10
Q

Thiamine
Riboflavin
Niacin

sources

A

whole and enriched grains

Thiamin - legumes (decreased in polished rice)

Riboflavin - dairy, eggs, meat

Niacin: meat/poultry (tryptophan = precursor)

*corn is a poor source unless alkaline-treated

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11
Q

Thiamin deficiency

A

BeriBeri - Nervous and cardiovascular systems

Dry - peipheral neuropathy - weakness and atrophy

Wet - edema, CHF

Wernicke-Korsakoff (Cerebral) - confusion, ophthalmoplegia, ataxia, memory loss

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12
Q

Thiamin deficiency

who is at risk?

A
alcoholic 
voming 
s/p bariatric surgery 
TPN
AN
Re-feeding 
Endemic in So Asia - polished rice
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13
Q

Infantile beriberi

A

infant formula w/o thiamin
- vomiting / infection / lethargy / ophthalmoplegia / low thiamine PPi

Prompt response to high dose (50mg/d x 2wk)

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14
Q

Riboflavin deficiency

A

Cheilosis
Angular stomatitis

Low dairy, animal products, common in low resource setting

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15
Q

Niacin deficiency

A
Pellagra (D4)
Dermatitis
Dementia 
Diarrhea
Death
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16
Q

Dermatitis in Niacin deficiency

A

scaling with areas of depigmentation and hyperpigmentation - aggrevated by sun

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17
Q

Niacin deficiency predisposing factors

A

Nutritional/dietary restriction
cornmeal based diet

Malabsorption

Alcoholism

Metabolic shuting (carcinoid tumor)

18
Q
Folic acid (Folate)
Functions
A

single carbon transfers

  • nucleic acid synthesis
  • amino acid metabolism
  • epigenetics (methylation)
19
Q
Folic acid (folate)
sources
A

foliage -
orange juice
whole grains - enriched
easily destroyed in prolonged cooking

20
Q

risk of folate deficiency

A

inadequate intake or increased destruction of food

alcoholics

pregnancy - globally higher rates

hematopoietic conditions
drug/nutrient interactions

21
Q

folate deficiency

signs and symptoms

A
macrocytic anemia 
hypersegmented nuets
glossitis
irritability 
homocysteinemia 
(above are reversible)
neural tube defects
22
Q

folate supplementation

A

400-800microgram/day for women of child bearing age - to prevent neural tube defects
important pre-conceptus as neural tube closes 4-6wk gestation

23
Q

VitB12 cobalamin

functions

A

reforms THF from methylfolate (necessary for synthesis of methionine)

catabolism of odd chain FA

isomerization of methylmolonyl CoA to succinyl CoA (lipid and CHO metabolism)

One carbon transfers (methylation)

METABOLISM INTIMATELY RELATED TO FOLATE

Interactions essential for homocysteine –> methionine, protein synthesis, nucleic acid synthesis

24
Q

VitB12 absorption
stomach?
ilieum?

A

requires IF from stomach

Cobalamin-IF absorbed in distal ileum

Transport in circulation as transcobalaminII

25
VitB12 absorption storage excretion
enterohepatic circulation large liver stores excretion: primarily via bile
26
Vit B12 sources
only in animals synthesized in soil bacteria vegans should take supplement
27
B12 deficiency at risk?
inadequate IF or antibodies to IF Gatric atrophy Ileal resection Breasfed infant of B12 deficienct mom
28
B12 deficiency effects?
Macrocytic anemia Hyperseg nuets nuerologic disturbance - depression / parasthesias / dizzy / gait
29
B12 deficiency | reversible effects?
Hematologic effects are reversible with B12 or folate neurological effects eventually irreversible MEGALOBLASTIC ANEMIA SHOULD NOT BE TREATED WITH FOLATE UNLESS B12 RULED OUT!!
30
Vitamin C | Functions
Cosubstrate in hydoxylation: collagen synthesis ; seratonin synthesis from typtophan Converstion of Dopamine to norepinephrine Reversible antioxidant Reduction of iron --> increased absorption Leukocyte function
31
VitC food sources
``` Fruits and Veggies US 39% F 15% Potatoes 38% other vegetables ```
32
VitC intake/absorption
Saturable If taking large doses divid into <1g/dose
33
VitC absorption homeostasis
if you increase intake the GI will decrease absorption Renal excretion limits plasma levels Intakes of 400-500mg --> no increase in plasma concentration
34
VitC deficiency
``` Scurvy Hemmorhagic signs Hyperkeratosis of hair follicles Hypochondriasis Hematologic anomalies - anemia - iron or folate deficiencies ```
35
VitC deficiency progression
weakness - aching - joints - bones - muscles - hemorrhagic
36
Scurvy in children
Autism link
37
Benefits of megadoses of VitC?
Common cold - decrease duration of symptoms? | Wound healing -
38
6 mo old breastfed infant, vomiting, ophthalmoplegia, CHF
Beriberi - wet - Thiamin
39
5 year old eats only burgers with bun and milk, now limping and refusing to walk, with "rash"
Scurvy - vitamin C
40
Alcoholic "found down" altered mental and anemic
Could be thiamin or folate
41
Obese adolescent s/p bariatric surgery, can't walk, falls down
Thiamin (BeriBeri)
42
Adult, low SES, chronic diarrhea, malabsorption, rash on arms, hands, neck
Niacin