Water Soluble Vitamins Flashcards Preview

DEMS: Unit IIb > Water Soluble Vitamins > Flashcards

Flashcards in Water Soluble Vitamins Deck (33)
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1

Characteristics of water soluble vitamins

  • Generally not “stored” in body
    •   (B12 = exception)
  • Chronic intakes do alter tissues levels
  • Toxicity usually low
    •   (B6 = exception)
  • Absorption usually high
  • Excretion typically via urine

2

Major B vitamins

  • Thiamin (B1)
  • Riboflavin (B2)
  • Niacin (B3)

3

B vitamins: Biochemical/physiologic fxn

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

4

Thiamine: biochemial fxn

  • Coenzyme for rx central to intermediary metabolism in all cells
    • esp. glycolysis, TCA cycle, amino acid metabolism
  • PDH coenzyme

5

Riboflavin (B2): Biochemical fxns

  • Part of coenzymes: FAD & FMN are dervied from B2

  • Glycolysis

  • TCAC

6

Vit B3: Biochemical fxns

  • Constituent of NAD & NADP
  • Energy pathways
  • Glycolysis
  • TCAC

7

Folate: Biochemical fxns

  • Important in 1-carbon transfers
  • think about epigenetics and gene expression in current research

8

Vit B12: Biochemical fxns

  • Closely related to folate metabolism and 1-carbon transfers;
  • Odd chain length fatty acid
  • catalyze isomerization of methylmalonyl Co-A to succinyl Co-A (essential to lipid and CHO metabolism).

9

Thiamine (B1): Physiologic Metabolic Role

  • Decarboxylation and transketolation reactions;
  • functions in nerve conduction
    • Thiamin pyrophosphate (TTP) thought to bind at Na+ channel @ n. membranes

10

Riboflavin (B2): Physiologic Metabolic Role

  • Oxidation/reduction reactions in Krebs cycle & oxidative phosphorylation
  • Amino acid & FA metabolism
  • Vit K, Folate B6 & B3 metabolism

11

Niacin (B3): Physiologic Metabolic Role

  • Glycolysis, Kreb cycle
  • oxidative phosphorylation
  • FA synthesis & oxidation

12

Folate: Physiologic Metabolic Role

  • Synthesis of nucleic acids and for metabolism of certain amino acids
  • conversion homocysteine → methionine

13

Thiamine (B1): Major dietary sources

  • Whole & enriched grains
  • Lean pork
  • Legumes

14

Riboflavin (B2): Major dietary sources

  • Dairy + Animal Products
  • Wheat germ, Almonds,
  • Leafy greans

15

Niacin (B3): Major dietary sources

  • RDA: 14-16 mg/d
  • Dairy
  • Eggs
  • Enriched breads and cereals
  • Fish
  • Lean meats
  • Legumes
  • Nuts
  • Poultry

16

Folate: Major dietary sources

Foliage → deep green leaves, broccoli, orange juice, whole grains  (easily destroyed with prolonged cooking)

17

Thiamine (B1): Characteristic deficiency findings

  • Triad: ocular, ataxia, mental confusion/amnesia
  • Beriberi (think: Ber1ber1 for B1)
    • Dry berberi → peripheral neuropathy,
    • Wet berberi → edema, CHF
    • Cerebral berberi →  Wernicke- Korsakoff

18

Riboflavin (B2): Characteristic deficiency findings

  • Oral-ocular-genital syndrome:
  • 2 Cs:
    • Corneal vascularization
    • Cheilosis/stomatitis → cracks at angles of mouth

19

Niacin (B3): Characteristic deficiency findings

  • Pellagra 4Ds →  dermatitis, dementia, diarrhea, death
  • Rash is scaly, has areas of depigmentation and hyperpig,  photosensitive.
  • Glossitis.

20

Folate: Characteristic deficiency findings

  • Macrocytic anemia, hypersegmented neutrophils
  • glossitis, irritability
  • increased plasma homocysteine
  • Neural tube defects

21

Vit C (Absorbic Acid): Biochemical fxns

  • Antioxidant/
  • Reducing agent → electron donor
  • Co-substrate in hydroxylation:
    • collagen synthesis
    • (C = collagen)
  • Reduction of Fe3+ → Fe2+ (absorption)

22

Vit C (Absorbic Acid): Physiologic Metabolic Role

  • Collagen Synthesis
  • NT synthesis:
    • trp → serotonin
    • dopa → NE
  • Iron absorption
  • Leukocyte fxn

23

Vitamin B12 (cobalamin): Characteristic deficiency findings

  • Macrocytic anemia, hypersegmented neutrophils.
  • Neurologic disturbances: paresthesias, gait problems, depression, dizziness, burning tongue
    • initially reversible, irreversible eventually

24

Vitamin C: Characteristic deficiency findings

Scurvy: swollen gums, bruising, anemia, poor wound healing, weakness, aching joints / bones/ muscles, hemorrhagic signs


Loss of precursors of catecholamines & other vasoactive & neurotropic substances

25

Vitamin B12: Major dietary sources

  • Animal products only
  • Eggs
  • Meat
  • Milk
  • Poultry
  • Shellfish

26

Vitamin C: Major dietary sources

  • fruits
  • veggies

27

Thiamine (B1): Risk for deficiency/toxicity

  • Alcoholics
  • Anorexia
  • Bariatric surgery

28

Riboflavin (B2): Risk for deficiency/toxicity

  • Women, infants, elderly, adolescents
  • Diets lacking major sources
  • Sub-clinical deficiency: oral contraceptives, elderly, eating disorders, etc.

29

Niacin (B3): Risk for deficiency/toxicity

  • Nutritional restriction, malabsorbtion,
  • alcoholism
  • metabolic shunting

30

Folate: Risk for deficiency/toxicity

  • Premature infants, pregnancy
  • Alcoholics
  • Chronic hemolytic anemia or blood loss
  • Medications:
    • Phenytoin (seizures)
    • sulfasalazine (IBD)