Fat Soluble Vitamins Flashcards
To be familiar with sources
What are sources for Vitamin A?
Liver, eggs, whole milk, butter
Beta carotene from carrots and sweet potatoes
What are effects of Vitamin A toxicity?
Hypervitaminosis A
Membrane lysis and tissue damage
Excessive dryness of skin, desquamation, alopecia
Hepatomegaly, Cirrhosis
Pseudotumor cerebri (headache, nausea, ataxia)
Thickening of long bones, hypercalemia, calcification of long bones
Teratogenicity
What is another name for Vitamin D2 and D3?
D3 is cholecalciferol, D2 is ergocalciferol
Where is Cholecalciferol derived?
Vit D3 is formed in the skin from 7 dehydrocholesterol when exposed to sunlight. Other sources include fatty fish, liver, egg yolk
Where does activation of Vit D occur and what is the product?
It occurs in the liver and kidney. The product is calcitriol or 1,25 dihydroxyvitamin D
What are sources of tocopherols and tocotrienols?
Vegetable oil, liver and eggs
What are results of tocopherol deficiency?
Nerve and muscle membrane damage
What are sources of phylloquinone?
Green vegetables
What are sources for menaquinone and menadione?
Menaquinone in synthesized by intestinal bacteria, Menadione is a synthetic compound
What are sources of thiamine?
Pork, fish, seafood, beef, yoghurt, fortified rice, cereals, beef and flour
Thiamine is a coenzyme for which enzymes?
Pyruvate dehydrogenase, a ketoglutarate dehydrogenase, branched chain amino acid dehydrogenase, transketolase
What are clinical entities that arise from thiamine deficiency?
Infantile beriberi - tachycardia, vomiting, seizures and death
Adult beriberi- dry skin, irritability, disordered thinking, progressive paralysis
Wernicke encephalopathy - confusion, ataxia, nystagmus, ophtalmoplegia
Korsakoff - amnesia, confabulation, hallucinations
Vit B2 is derived from what sources?
Milk and eggs
What are symptoms of Vit B2 deficiency?
Seborrheic dermatitis, cheilosis, angular stomatitis, desquamation and inflammation of the tongue
What is the amino acid precursor for Vitamin B3?
Tryptophan is the precursor for niacin, and requires pyridoxine
What are sources of niacin?
Grains, cereal, milk, lean meat and liver
TRUE OR FALSE
The etiologies for niacin deficiency include isoniazide use
TRUE. Etiologies of pellagra (diarrhea, dermatitis, dementia) include corn based diet, hartnup disease, carcinoid syndrome, isoniazid disease
What is the active form of Vitamin B 5?
The active form of pyridoxine is pyridoxal 5 phosphate
What are sources of pyridoxine?
Potatoes and other starchy vegetables, Non citrus fruits, pyridoxal from pyridoxamine from meat
Pyridoxine is the coenzyme for what reactions
Transamination of amino acids
Decarboxylation of glutamate and histidine, ala synthase, crystathionine synthase, synthesis od niacin from tryptophan, glycogen phosphorylase
What is the only water soluble vitamin with significant toxicity?
Pyridoxine causing sensory neuropathh
What are sources of Vitamin B12?
Sources for cobalamin include
Liver, whole milk, eggs, oysters, shrimp, pork, chicken
Vitamin B12 is the coenzyme for which enzymes?
Methionine synthase and methylmalonyl coA mutase
Ascorbic acid is the coenzyme for what enzymes?
Copper and iron containing hydroxylases such as
Proline and lysine hydroxylases in collagen, dopamine beta hydroxylase
What inhibits absorption of Vitamin H?
Avidin in egg whites inhibits absorption of Vitamin H or Biotin
Vitamin H is the conezyme for which enzymes?
Pyruvate Carboxylase
Acetyl coA carboxylase
Propionyl coA carboxylase
What are the specific tests for vitamin deficiencies
Vitamin B1 - erythrocyte transketolase activity assay
Vitamin B6 - erythrocyte transaminase assay
Vitamin B12 - Schilling test, Methylmalonic acid test
Folate - Formiminoglutamic acid excretion test
