Water Soluble Vitamins Flashcards Preview

DEMS Unit 2 Part 2 > Water Soluble Vitamins > Flashcards

Flashcards in Water Soluble Vitamins Deck (21):
1

Beriberi

- Thiamin B1 Deficiency
- "Dry" = peripheral neuropathy; muscle tenderness, weakness & atrophy; foot drop
- "Wet" = edema, circulatory collapse, CHF
- Wernicke-Korsakoff (cerebral beriberi): confusion, opthalmoplegia, ataxia, memory loss

2

Food sources for thiamin riboflavin, and niacin

Thiamin: pork, legumes
Riboflavin: dairy, eggs, meats
Niacin: meat/poultry; tryptophan = precursor

-All involved in glycolysis/Krebs cycle
-TPP, FAD, NAD; decarboxylation, oxidation-reduction

3

Risk for thiamin deficiency

- Alcoholics
- s/p bariatric surgery
- TPN
- Anorexia nervosa
- re-feeding
- endemic in So Asia

4

What physical symptoms do you get from B2 deficiency?

Riboflavin deficiency
- Cheilosis
- Angular stomatitis

5

What does B3 deficiency lead to?

Pellagra

- Malabsorption syndromes
- nutritional/dietary restriction
- Alcoholism
- Metabolic shunting (carcinoid tumor)

6

4 D's of Pellagra

- Diarrhea
- Dermatitis (scaling w/ areas of depigmentation and hyperpigmentation; aggravated by sun exposure - Casal's necklace)
- Dementia
- Death

7

Folic Acid

Function: Single C transfers for DNA methylation

Food sources:
- foliage, deep green veg
- orange juice
- whole grains

8

Situations with risk of folate deficiency

- inadequate intake or increased destruction in food
- alcoholics
- pregnancy
- hematopoietic conditions
- drug/nutrient interactions

9

Signs of folate deficiency

- macrocytic anemia (inc. MCV)
- hypersegmented neutrophils
- glossitis, irritability
- homocysteinemia
- NTD

10

How much folate should be taken to prevent NTD

400-800 micrograms/day

11

Vitamin B-12

- Forms tetrahydrafolate from methylfolat (synthesis of methionine)
- catabolism of odd chain length fatty acids
- catalyze isomerization of methylmalonyl Co-A to succinyl Co-A (lipid and CHO metabolism)
- methylation
- interactions essential for homocysteine --> methionine, protein synthesis, nucleic acid synthesis

12

Absorption of B12

- Cleave vitamin from dietary protein in stomach
- Requires IF from stomach
- Cobalamin-IF complex absorbed in distal ileum
- Transport into circulation with transport protein transcobalamin II

13

Food sources for B12

- soil bacteria
- animal products

vegans should take a supplement

14

Risk factors for B12 deficiency

- Inadequate IF secretion or antibodies to IF
- gastric atrophy/gastrectomy
- ileal resection
- breastfed infant of B12 deficient vegan mother

15

Effects of B12 deficiency

- macrocytic anemia & hypersegmented neutrophils
- neurologic disturbances (depression, paresthesias, gait disturbances, burning tongue, dizziness)

16

Vitamin C

Function:
- Reversible antioxidant, Vit E sparing
- Provides reducing equivalents to enzymes (reduction of iron --> inc. absorption
- Leukocyte function (inc. [Vit C] wbc
- co-substrate in hydroxylation --> collagen synthesis
- conversion dopamine --> NE

17

Sources of Vit C

F/V

18

Absorption of Vit C

- Active (saturable) process
- Low intake = 100% absorption
- Typical intake (30-180 mg/d) = 70-90% abs.
- Megadoses reduce your efficiency

If you take large doses, better to take them in divided doses for better absorption

-Renal excretion limits plasma levels
- intakes of 400-500 mg --> no inc. plasma concentration

19

Pool sizes of vit C

- 10 mg/d
- 1500 mg: maintained w/intake = prevents scurvy x 30-45 days with no intake
- 2300-2800 mg: acheived with 200mg/day + unmetabolized vit C in urine

20

Scurvy in kids

- Autistic children on restricted diets
- Refuse to walk
- Gingival hypertrophy

21

Benefits of megadoses of vit C?

- Prevent common cold? (antihistamine effects, neutrophil chemotaxis; dec duration symptoms
- Prevention of CVD, Ca (RCT do not support F/V)
- Wound healing: inflammation, proliferation, maturation