Lecture 11 Vitamins (Water Soluble)

Question 1

Water-soluble vitamins

Answer 1

• are easily absorbed and excreted (40-90% absorbed in small intestine)
• are not stored extensively in tissues
• Vitamin C
• Vitamins B (all 8)

Question 2

B Vitamins

Answer 2

• act as part of co-enzymes
• energy metabolism
• B1, B2, B3, B6, B12, folate, biotin, pantothenic acid

Question 3

Thiamin, B1

Answer 3

Functions:

• co-enzyme: thiamin pyrophostphate (active form)
• Glucose –> ATP
• Neurotransmitter Acetylcholine production

RDA (>19 years): M: 1.2mg/day; F: 1.1 mg/day

UL: N/A; may change due to needs - pregnancy, lactation, alcohol

Deficiency:
- beriberi (fatigue, weight loss, edema, nerve degeneration, irregular heart beat)

Toxicity: N/A

Food Sources:

• enriched white flour
• pasta
• whole grain
• legumes
• pork/ham

anti-thiamin factors: raw shellfish, heat

Question 4

Niacin, B3

Answer 4

Functions

• coenzymes: Nicotinamide Adenine Dinucleotide (NAD) –> Glycolysis, kreb cycle
• Nictinamide adenine dinucleotide phosphate (NADP) –> synthesize fatty acid, cholesterol

RDA (>19): M: 16mg/day; F: 14 mg/day

Food Sources:

• enriched white flour pastas
• legumes, wheat bran peanuts, chicken, pork, liver
• synthesized in our body

Deficiency:
- pellagra (diarrhea, dermatitis, dementia, death); fatigue, depression

Toxicity:
- niacin flush (painful flush, hives, rash, 2-3X RDA)

Question 5

Vitamin B6

Answer 5

Functions:

• coenzyme: pyridoxal phosphate
  1) protein and amino acid metabolism
  2) NT, myelin coating
  3) synthesize hemoglobin, WBC
  4) Tryptophan –> Niacin

RDA (>19): 1.3 mg/day
UL: 100mg/day; varies due to needs

Deficiency:

• Anemia
• numbness/tingling

Toxicity:
- nerve impairment

Food Sources:

• Fortification: meal replacement products
• plants/animals

Sensitive to heat/light

Question 6

Folate/Folic acid

Answer 6

Functions:
-synthesis DNA, Cell division

RDA (>19): 400 ug/day
UL: 1000 ug/day

Deficiency:

• Spina Bifida
• Macrocytic anemia

Toxicity:
- mask symptoms of B12 deficiency

Food sources:

• greens, beans
• folic acid is in fortified foods

Question 7

Vitamin B12

Answer 7

Contain cobalt (metal ion)

Functions:

• proteim catabolism
• folate coenzyme function
• hemoglobin synthesis
• myelin sheath formation

RDA (>19) 2.3 ug/day
UL: 100 ug/day

• absoption requires intrinsic factor (Parietal cells)

Food sources:
- animal origin

Deficiency:

• pernicious anemia
  
  • autoimmune, needs IF
• atrophic gastritis
  
  • HCl reduced
• vegan diet
  
  • no animal source

Question 8

Vitamin C

Answer 8

Functions:
- maintaining connective tissues

Antioxidant:
- protects iron from oxidation and promotes its absorption

DRI recommendation:

• M: 90 mg/day
• F: 75 mg/day

UL: 2,000 mg/day
- Tobacco use increases DRI recommendations

Deficiency:

• scurvy (rare today) (< 10mg/day)
• bleeding gums
• pinpoint hemorrhages (red spots)
• fatigue

Toxicity:

• > 10,000 g/ day
• interferes with insulin response to carbohydrate
• digestive upset
• mouth ulcers
• kidney stones

Question 9

multivitamins?

Answer 9

Good if you’re pregnant, elderly, young, strict vegetarian, AIDS or other wasting illness otherwise you can make do with what you get in food