Vitamins Flashcards
which vitamins are fat soluble?
A,D,E,K
which vitamins are water soluble?
B vitamins, C
describe vitamin A
action: antioxidant, in retinal pigments, differentiation of epithelial cells
treats: measles, AML (M3), topically used for wrinkles/acne
what happens with vitamin A deficiency?
- night blindness (nyetalopia)
- dry/scaly skin (xerosis cutis)
- alopecia
- corneal degeneration (keratomalacia)
- immune suppression
what happens with excess vitamin A?
- arthralgias
- skin changes
- alopecia
- cerebral edema
- pseudotumor cerebri
- osteoporosis
- hepatic changes
- teratogenic changes
describe vitamin B1
=thiamine
-cofactor for pyruvate DH, alpha-KG DH, transketolase, BCKA DH
how is vitamin B1 deficiency diagnosed?
by increase in RBC transketolase activity after administering B1
what happens in B1 deficiency and what conditions can it cause?
- impaired glucose breakdown -> deplete ATP
- affects highly aerobic tissues first (heart, brain)
- seen in malnutrition and alcoholism
can cause: Wernicke-Korsakoff or wet/dry BeriBeri
describe Wernicke-Korsakoff symptoms
- confusion
- confabulation
- ataxia
- ophthalmoplegia
- memory/personality changes
describe wet vs. dry beriberi
wet: B1 deficiency + high output cardiac failure, edema
dry: B1 deficiency + polyneuritis, symmetrical muscle wasting
describe vitamin B2
= riboflavin
-part of FMN, FAD -> cofactor in redox reactions (succinate DH)
what happens in B2 deficiency?
“2 C’s for B2”
- cheilosis (inflammation of lips, scaling/fissuring of mouth corners)
- corneal vascularization
describe vitamin B3
=niacin
- part of NAD+, NADP+ -> used in redox reactions
- comes from Trp
- its synthesis requires B2 and B6
- treats dyslipidemia (lowers VLDL, raises HDL)
what happens in B3 deficiency?
“3 D’s of B3”
- diarrhea, dementia, dermatitis (symptoms of pellagra)
- can be caused by Hartnup disease (loss of Trp absorption)
what happens with excess B3?
- facial flushing due to prostaglandins
- hyperglycemia
- hyperuricemia
describe vitamin B5
=pantothenate (remember “B5 = PENTOthenate”)
- part of CoA
- essential for FA synthase
what happens in B5 deficiency?
- dermatitis
- enteritis
- alopecia
- adrenal insufficiency
describe vitamin B6
=pyridoxine
- part of PLP -> for transaminations, decarboxylations, and glycogen phosphorylase
- needed for synthesis of cystathione, heme, niacin, histamine, and some neurotransmitters
what happens in B6 deficiency?
- microcytic/sideroblastic anemias
- convulsions
- hyperirritability
- peripheral neuropathy
describe vitamin B7
=biotin
-for carboxylations (adds 1C) -pyruvate carboxylase, acetyl-coA carboxylase, propionyl-coA carboxylase
what happens in B7 deficiency?
(this is rare)
- dermatitis
- alopecia
- enteritis
what can cause B7 deficiency?
- antibiotic use
- excessive ingestion of raw egg whites (contain avidin)
describe vitamin B9
=folate/folic acid
- part of THF for 1-C transfer reactions or methylations
- needed for synthesis of N bases in DNA and RNA
- found in leafy green veggies
what happens in B9 deficiency?
- macrocytic, megaloblastic anemia
- NO NEURO SYMPTOMS
- increased HomoCys levels, but normal methylmalonyl levels
- hypersegmented PMNs
*most common vitamin deficiency in U.S.
what can cause B9 deficiency?
- pregnancy (can cause neural tube defects in child - spina bifida)
- alcoholism
- the drugs phenytoin, sulfonamides, methotrexate
describe vitamin B12
= cobalamin
- cofactor for HomoCys methyltransferase and methylmalonyl-coA mutase
- found in animal products
- large reserve stored in liver
what happens in B12 deficiency?
- macrocytic, megaloblastic anemia
- NEURO SYMPTOMS
- increased HomoCys AND methylmalonyl levels
- hypersegmented PMNs
- prolonged deficiency leads to irreversible nerve damage
what can cause B12 deficiency?
- insufficient intake (veganism)
- malabsorption
- lack of intrinsic factor (pernicious anemia, gastric bypass)
- absence of terminal ileum (Crohn’s)
what is diagnostic for pernicious anemia?
anti-intrinsic factor antibodies
describe vitamin C
= ascorbic acid
- antioxidant
- reduces iron to Fe2+ state for absorption
- needed for hydroxylation of Pro and Lys (collagen)
- needed for dopamine B-hyroxylase (dopamine -> norepi)
what happens in vitamin C deficiency?
- scurvy (swollen gums, bruising, hemarthrosis, anemia, poor wound healing, “corkscrew” gait)
- weakened immune response
what happens with excess vitamin C?
- nausea, vomiting, diarrhea
- fatigue
- calcium oxalate nephrolithiasis
- increased risk of Fe toxicity
describe vitamin D
- D2 = ergocalciferol (ingested from plants)
- D3 = cholecalciferol (ingested from milk, formed by sun)
- increases intestinal absorption of calcium, phosphate
- increases bone mineralization
what are the storage and active forms of D3?
storage: 25-OH D3
active: 1,25-(OH)2 D3 (calcitriol)
what happens in vitamin D deficiency?
- Rickets in kids (bone pain/deformity)
- osteomalacia in adults (bone pain/muscle weakness)
- hypocalcemic tetany
exacerbated by low sun exposure, pigmented skin, prematurity
what happens with excess vitamin D?
- hypercalcemia
- hypercalciuria
- loss of appetite
- stupor
seen in sarcoidosis
describe vitamin E
=tocopherol, tocotrienol
- antioxidant (protects RBCs and membranes from ROS)
- can enhance anticoagulant effects of warfarin/Coumadin
what happens in vitamin E deficiency?
- hemolytic anemia
- acanthocytosis
- muscle weakness
- posterior column and spinocerebellar tract demyelination
neuro presentation similar to B12 deficiency, but no megaloblastic anemia or increased serum methylmalonyl
describe vitamin K
-cofactor for gamma carboxylations in blood clotting
-needed for activation of clotting factors 2,7,9,10 and proteins C and S
(warfarin = vitamin K antagonist)
-made by intestinal flora
what happens in vitamin K deficiency?
- neonatal hemorrhage with increased PT and aPTT (increased clotting time) but normal bleeding time
- also caused by prolonged use of broad-spectrum antibiotic
describe zinc
- essential for 100+ enzymes
- important in forming zinc fingers (DNA-binding domains)
what happens in zinc deficiency?
- delayed wound healing
- hypogonadism
- decreased adult hair
- dysgeusia
- anosmia
- acrodermatitis enteropathica
-predisposes to alcoholic cirrhosis
what happens in copper deficiency and copper excess?
def: Menke’s disease (hair, collagen defects)
excess: Wilson’s disease (brain, liver toxicity, caused by defective transport protein -> Cu accumulates in liver)
what happens in iodine deficiency?
goiter and hypothyroidism
what is cobalt needed for?
component of B12
