Vitamins - Fat Soluble (Krasowski)

Question 1

analogs of this vitamin are used in the treatment of psoriasis and some other auto-immune diseases (e.g. calcipotriene)

Answer 1

vitamin D

Question 1

higher overall levels of this vitamin inhibits tumor growth and differentiation and may reduce the risk of multiple sclerosis

Answer 1

vitamin D

Question 2

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

Answer 2

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.

Question 4

the main storage form of vitamin D, and its measurement is the test for assessing vitamin D nutritional status

Answer 4

25-OH

Question 4

the conversion of 25-OH to 1,25 dihydroxy mainly occurs here, but some tumors make this conversion as well, inhibiting their own growth

Answer 4

kidney

Question 6

cholesterol sequesterants that may bind fat souble vitamins, leading to deficiency

Answer 6

bile acid resins

Question 6

True or false: 1,25 dihyrdoxy measurement is a standard test for vitamin D nutritional status.

Answer 6

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.

Question 7

the form of vitamin D that controls expression of genes involved in cellular proliferation, differentiation, apoptosis, and angiogenesis

Answer 7

1,25 dihydroxy

Question 8

what are the 4 essential fat soluble vitamins?

Answer 8

A, D, E, K

Question 8

Fat soluble or water soluble? Which is more easily stored long term and requires bile and pancreatic enzymes for absorption?

Answer 8

fat soluble

Question 9

group of related compounds that act sometimes as hormones and come from animal (pre-formed) or plant (carotenoid) sources

Answer 9

vitamin A

Question 10

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)

Answer 10

vitamin A

Question 10

tissue stores of this vitamin usually have an ~3 week reserve, typically the least reserves of the four fat-soluble vitamins

Answer 10

vitamin K

Question 11

vitamin deficiency associated with night blindness and epithelial metaplasia/keratinization

Answer 11

vitamin A

Question 11

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

Answer 11

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.

Question 12

True or false: you can get vitamin D toxicity by spending too much time in the sun.

Answer 12

False. Excess previtamin D3 is destroyed by sunlight

Question 14

Most biologically active form of vitamin D - not a good measurement of vitamin D nutritional status, as levels vary day to day

Answer 14

1,25 dihydroxy

Question 15

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

Answer 15

E. In cystic fibrosis, exocrine pancreas dysfunction leads to insufficiency of pancreatic enzymes and fat malabsorption.

Question 17

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?

Answer 17

vitamin A

Question 18

vitamin deficiency that causes growth retardation and bone deformities (rickets in young children) as well as increased risk for fractures later in life

Answer 18

vitamin D

Question 19

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.

Answer 19

granulomatous

Question 19

the main recognized biological function of this vitamin is as anti-oxidant, though it is also thought to preserve neurological function

Answer 19

vitamin E

Question 20

what are the 9 essential water soluble vitamins?

Answer 20

Vitamins B1 (thiamin) B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pryidoxine), B12

Vitamin C

Folate

Biotin

Question 22

True or false: vitamin D3, also known as cholecalciferon, is made endogenously in animals

Answer 22

True. Vitamin D2 (ergocalciferol) is acquired from plants, fungi and invertebrates. Either is an effective supplement to food.

Question 23

Which of the following would be an appropriate indication for ordering a 1,25-dihydroxyvitamin D (calcitriol) plasma level? A. Nutritional screening in an adolescent girl B. Renal failure with persistent hypocalcemia C. Recent switch to vitamin D2 supplements D. Severe sunburn E. Vitamin D screening in a 9-month old infant with collarbone fracture

Answer 23

B. In renal failure, inability to produce 1,25-dihydroxyvitamin D can produce persistent hypocalcemia even with normal 25-OH levels

Question 25

All-trans-retinoic acid (ATRA) is able to induce remission in this cancer type, as it causes cells to differentiate and be less prone to causing bleeding and clotting problems

Answer 25

acute promyelocytic leukemia (APL)

Question 26

Main dietary sources of this anti-hemorrhagic vitamin include cabbage, cauliflower, spinach, and other leafy vegetables

Answer 26

vitamin K (vitamin K1 is found in plants, vitamin K2 is endogenous and made by gram-positive bacteria in the intestinal tract)

Question 27

biological roles of this vitamin include maintenance or normal vision, cell growth and differentiation, metabolic effects of retinoids, and host resistance to infections

Answer 27

vitamin A

Question 27

deficiency of this vitamin leads to decreased serum Ca and P and poor bone mineralization

Answer 27

vitamin D

Question 28

Vitamin ____ is relatively heat stable so that warming milk does not affect its levels very much

Answer 28

D

Question 30

the major form of this vitamin is α-tocopherol, and deficiency can occur in individuals who have diets low in vegetable oils and fresh green vegetables

Answer 30

vitamin E

Question 31

which vitamins are made endogenously?

Answer 31

Vitamins D, K and B3 (niacin)

Question 33

this precursor to vitamin D3 is reduced in the skin during the aging process, leading to an eventual 75% loss in vitamin D production

Answer 33

7-dehydrocholesterol

Question 34

form of vitamin D that is tightly regulated by the parathyroid hormone, and controls serum Ca and Phos levels

Answer 34

1,25 hyrdroxy

Question 35

signs of toxicity of this vitamin include coagulopathy and decreased wound healing, as well as sepsis and necrotizing enterocolitis in premature infants

Answer 35

vitamin E

Question 36

this commonly prescribed oral anticoagulant interferes with vitamin K-dependent activation of clotting factors by blocking vitamin k epoxide reductase; its related compounds are used in rat poison

Answer 36

warfarin