What is the function of vitamin A?
- Constituent of visual pigments
- essential for normal differentiation of epithelial cells into specialized tissue (pancreatic cells, mucus-secreting cells)
- Treat measles
What is seen with vitamin A deficiency?
- Night blindness
- dry skin
- bitot skin
- lung -> squamos epithelium
What is seen with vitamin A excess?
Arthragias, fatigue, headaches, skin changes, sore throat, alopecia. Teratogenic
What is the function of Vitamin B1
- cofactor for:
- Pyruvate dehydrogenase (glycolysis)
- a-ketoglutarate dehydrogenase (TCA cycle)
- Transketolase (HMP shunt)
- Branched-chain AA dehydrogenase
What is seen with a vitamin B1 deficiency?
- Impaired glucose breakdown -> ATP depletion
- Wernicke-Korsakoff (confusion, opthalmplegia, ataxia, confabulation)
Dry beriberi = polyneuritis, symmetrical muscle wasting
Wet beriberi = high output cardiac failure (dilated cardiomyopathy), edema
What is the function of vitamin B2?
- Cofactor in oxidation and reduction (FADH2 and FMN) :
- Succinate dH (TCA)
- fatty acyl dH (B-oxidation)
- Glycerol dH (electron from cytoplasm to mitochondria)
What is seen with a vitamin B2 deficiency?
- Cheilosis, corneal vascularization
- Magenta-colored tongue
What is the function of vitamin B3?
- Derived from tryptophan with vitamin B6
- Constituent of NAD+ & NADP+
What is seen with a vitamin B3 deficiency?
- Pellagra (Diarrhea, Dermatitis, Dementia) from:
- Hartnup disease (decrease tryptophan absorption)
- malignant carcinoid syndrome (increased tryptophan metabolism)
- INH (decrease vitamin B6)
What is seen with a vitamin B3 excess?
Facial flushing (when given for hyperlipidemia treatment)
What is the function of vitamin B5?
- Essential component of CoA and fatty acid synthase:
- Fatty acyl CoA synthase
- Pyruvate dehydrogenase
- a-ketoglutarate dehydrogenase
What is seen with a vitamin B5 deficiency?
- adrenal insufficiency
What is the function of Vitamin B6?
PYRIOXINE (converted to pyridoxal phosphate)
- Cofactor in:
- decarboxylation reaction
- glycogen phosphorylase
- cystathionine synthesis
- heme synthesis
- synthesis of niacin from tryptophan
What is seen with a deficiency in Vitamin B6?
- peripheral neuropathy(INH & oral contraceptives)
- sideroblastic anemias, cheilosis
What is the function of vitamin B 12?
cofactor for homocysteine methyltransferase and methylmalonyl-CoA mutase
What is seen with a vitamin B12 deficiency?
- Macrocytic, megaloblastic anemia
- hypersegmented PMN's
- neurologic (paresthesias, subacute combined degeneration) due to abnormal myelin