Water Soluble Vitamins

Question 1

Characteristics of water soluble vitamins

Answer 1

• 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

Question 2

Major B vitamins

Answer 2

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

Question 3

B vitamins: Biochemical/physiologic fxn

Answer 3

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

Question 4

Thiamine: biochemial fxn

Answer 4

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

Question 5

Riboflavin (B₂): Biochemical fxns

Answer 5

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

Question 6

Vit B₃: Biochemical fxns

Answer 6

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

Question 7

Folate: Biochemical fxns

Answer 7

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

Question 8

Vit B₁₂: Biochemical fxns

Answer 8

• 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).

Question 9

Thiamine (B₁): Physiologic Metabolic Role

Answer 9

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

Question 10

Riboflavin (B₂): Physiologic Metabolic Role

Answer 10

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

Question 11

Niacin (B₃): Physiologic Metabolic Role

Answer 11

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

Question 12

Folate: Physiologic Metabolic Role

Answer 12

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

Question 13

Thiamine (B₁): Major dietary sources

Answer 13

• Whole & enriched grains
• Lean pork
• Legumes

Question 14

Riboflavin (B₂): Major dietary sources

Answer 14

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

Question 15

Niacin (B₃): Major dietary sources

Answer 15

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

Question 16

Folate: Major dietary sources

Answer 16

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

Question 17

Thiamine (B₁): Characteristic deficiency findings

Answer 17

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

Question 18

Riboflavin (B₂): Characteristic deficiency findings

Answer 18

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

Question 19

Niacin (B₃): Characteristic deficiency findings

Answer 19

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

Question 20

Folate: Characteristic deficiency findings

Answer 20

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

Question 21

Vit C (Absorbic Acid): Biochemical fxns

Answer 21

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

Question 22

Vit C (Absorbic Acid): Physiologic Metabolic Role

Answer 22

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

Question 23

Vitamin B₁₂ (cobalamin): Characteristic deficiency findings

Answer 23

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

Question 24

Vitamin C: Characteristic deficiency findings

Answer 24

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

Loss of precursors of catecholamines & other vasoactive & neurotropic substances

Question 25

Vitamin B₁₂: Major dietary sources

Answer 25

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

Question 26

Vitamin C: Major dietary sources

Answer 26

• fruits
• veggies

Question 27

Thiamine (B₁): Risk for deficiency/toxicity

Answer 27

• Alcoholics
• Anorexia
• Bariatric surgery

Question 28

Riboflavin (B₂): Risk for deficiency/toxicity

Answer 28

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

Question 29

Niacin (B₃): Risk for deficiency/toxicity

Answer 29

• Nutritional restriction, malabsorbtion,
• alcoholism
• metabolic shunting

Question 30

Folate: Risk for deficiency/toxicity

Answer 30

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

Question 31

Vitamin B₁₂: Risk for deficiency/toxicity

Answer 31

• Pernicious anemia
• Gastric atrophy
• Resection of stomach or ileum
• Strict vegan diet
• Breastfed infant of deficient mother

Question 32

Vitamin C: Risk for deficiency/toxicity

Answer 32

• Infants fed cow’s milk without supplementation
• Diets lacking in fruits and vegetables, ­
• ↑ requirements of vit C for wound healing & burns;
• Low income → associated with poor diet quality;
• Smokers

Question 33

Summary Table of Vit Deficiency Sx

Answer 33