Flashcards in Nutrition Deficiencies Deck (83)
Function of Vit A
- Liver, leafy vegetables
- Visual pigment
- Normal differentiation of epi cells into specialized tissue (pancreatic cells, mucus-secreting cells)
- Prevents squamous metaplasia
What is Vit A used to treat?
- AML subtype M3 (all-trans retinoic acid)
- Severe cystic acne
Vit A Deficiency
- NIGHT BLINDNESS (nyctalopia)
- Dry, scaly skin (xerosis cutis)
- Corneal degeneration (keratomalacia)
- Bitot spots on conjunctiva
Acute Vit A Toxicity
- N/v, vertigo, blurred vision
Chronic Vit A Toxicity
- Alopecia, dry skin, hepatic toxicity, arthralgias, pseudotumor cerebri (papilledema)
Enzymes thiamine pyrophosphate (B1) is cofactor for:
- Pyruvate dehydrogenase (glycolysis --> TCA)
- alpha-KG dehydrogenase (TCA)
- Transketolase (HMP shunt)
- Branched chain ketoacid dehydrogenase
Vit B1 Deficiency
- Impaired glucose breakdown --> ATP depletion worsened by glucose infusion (give thiamine before IV glucose)
- Highly aerobic tissues (brain, heart) are affected first
Who becomes Vit B1 deficient?
Malnutrition, alcoholism, countries where "polished rice" is staple
Dx of Vit B1 deficiency?
Increase in RBC transketolase activity following Vit B1 administration
Pyruvate dehydrogenase cofactors?
TPP, lipoic acid, CoA, FADH2, NADH
- Confusion, ophthalmoplegia, ataxia
- Confabulation, personality change, permanent memory loss
- Damage to medial dorsal nucleus of thalamus, mammillary bodies
Polyneuritis, symmetrical muscle wasting
High-output cardiac failure (dilated cardiomyopathy), edema
Vit B2 Function
Component of FAD and FMN
- Cofactors in redox rxns (ex. succinate dehydrogenase rxn in TCA cycle)
Vit B2 Deficiency
- Cheilosis (inflammation of lips, scaling and fissures at the corner of the moth)
- Corneal vascularization
- Magenta tongue
When can B2 supplementation be helpful?
Infants undergoing UV light therapy for neonatal jaundice
Vit B3 Function
- Constituent of NAD+, NADP+ (redox rxns)
What is niacin derived from?
What does niacin synthesis require?
B2 (riboflavin) and B6 (pyridoxine)
What is niacin used to treat?
Dyslipidemia - lower levels of VLDL and raises levels of HDL
Vit B3 Deficiency
Symptoms of pellagra?
- Diarrhea, dementia, dermatitis (C3/C4 dermatome circumfrential "broad collar" rash, hyperpigmentation of sun exposed skin)
Causes of pellagra?
- Hartnup disease
- Malignant carcinoid syndrome (increased tryptophan metabolism)
- Isoniazid (decreased Vit B6)
- Deficiency of neutral AA (ex. tryptophan) transporters in proximal renal tubule and on enterocytes --> neutral aminoaciduria and decreased absorption from gut --> decreased tryptophan conversion to niacin --> pellagra-like sx
- Rx: high-protein diet and nicotinic acid
Vit B3 Excess
- Facial flushing (induced by PG, not HA) - can avoid by taking aspirin with niacin
- Hyperglycemia, hyperuricemia (gout)