Vitamins - Fat Soluble (Krasowski) Flashcards
analogs of this vitamin are used in the treatment of psoriasis and some other auto-immune diseases (e.g. calcipotriene)
vitamin D
higher overall levels of this vitamin inhibits tumor growth and differentiation and may reduce the risk of multiple sclerosis
vitamin D
Which of the following is NOT a specific reason for vitamin D deficiency? A. Skin damage B. St. John’s Wort C. Hypocalcemia D. Liver failure E. Sunscreen
C. Hypocalcemia does not cause vitamin D deficiency, as vitamin D is the regulator of calcium absorption from the blood. Burns, malabsorption, organ failure, the use of sunscreen, and inucers of catabolism such as St. John’s Wort, anticonvulsants and some antibiotics (e.g., rifampin) are all reasons for vitamin D deficiency. Other reasons include nephrotic syndrome, granulomatous disease and poor diet.
the main storage form of vitamin D, and its measurement is the test for assessing vitamin D nutritional status
25-OH
the conversion of 25-OH to 1,25 dihydroxy mainly occurs here, but some tumors make this conversion as well, inhibiting their own growth
kidney
cholesterol sequesterants that may bind fat souble vitamins, leading to deficiency
bile acid resins
True or false: 1,25 dihyrdoxy measurement is a standard test for vitamin D nutritional status.
False. The only time 1,25 dihyrdoxy levels should be used to assess vitamin D status is when 25-OH levels have been measured and determined to be low, and there is persistent hypocalcemia, as this may indicate granulmoatous disease.
the form of vitamin D that controls expression of genes involved in cellular proliferation, differentiation, apoptosis, and angiogenesis
1,25 dihydroxy
what are the 4 essential fat soluble vitamins?
A, D, E, K
Fat soluble or water soluble? Which is more easily stored long term and requires bile and pancreatic enzymes for absorption?
fat soluble
group of related compounds that act sometimes as hormones and come from animal (pre-formed) or plant (carotenoid) sources
vitamin A
symptoms of toxicity related to this vitamin include desquamation (peeling skin), headache, dizziness, vomitng, stupor, and pseudotumor cerebri; may result from eating the liver of certain animals (ie polar bears)
vitamin A
tissue stores of this vitamin usually have an ~3 week reserve, typically the least reserves of the four fat-soluble vitamins
vitamin K
vitamin deficiency associated with night blindness and epithelial metaplasia/keratinization
vitamin A
Vitamin K is required for γ-carboxylation of the glutamate side-chains of which of these sets of blood clotting factors?
A. Protein C and von Willebrand’s factor
B. Factors V and X
C. Factors II and VIII
D. Factors VII and X
E. Factors I and IX
D. Vitamin K dependent factors include II, VII, IX, X and proteins C and S. The modifications to these factors made by vitamin K bind calcium, which allows for cross-bridging with phospholipids.
True or false: you can get vitamin D toxicity by spending too much time in the sun.
False. Excess previtamin D3 is destroyed by sunlight
Most biologically active form of vitamin D - not a good measurement of vitamin D nutritional status, as levels vary day to day
1,25 dihydroxy
Which of the following factors would MOST LIKELY be associated with combined deficiency of the “fat-soluble” vitamins (A, D, E, K)?
A. Therapy with high-dose niacin
B. Rheumatoid arthritis
C. Congestive heart failure
D. Vitamin B12 deficiency
E. Cystic fibrosis
E. In cystic fibrosis, exocrine pancreas dysfunction leads to insufficiency of pancreatic enzymes and fat malabsorption.
which vitamin is absorbed by a process that involves the conversion of β-Carotene to retinol in the intestine, and is then transported to the liver by chylomicrons and taken up by Apo E receptors?
vitamin A
vitamin deficiency that causes growth retardation and bone deformities (rickets in young children) as well as increased risk for fractures later in life
vitamin D
It is important to watch 25-OH levels in patients with _____ disease (e.g., histoplasmoisis, sarcoidosis, tuberculosis) because of excessive conversion to 1,25 dihydroxy, which may lead to hypercalcemia.
granulomatous
the main recognized biological function of this vitamin is as anti-oxidant, though it is also thought to preserve neurological function
vitamin E
what are the 9 essential water soluble vitamins?
Vitamins B1 (thiamin) B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pryidoxine), B12
Vitamin C
Folate
Biotin
True or false: vitamin D3, also known as cholecalciferon, is made endogenously in animals
True. Vitamin D2 (ergocalciferol) is acquired from plants, fungi and invertebrates. Either is an effective supplement to food.
