Flashcards in Vitamins I and II Deck (128)
Which vitamins are fat soluble?
Name 3 vitamins that are made endogenously
D, K, niacin
T/F- fat soluble vitamins are more easily stored long term than water soluble?
What two things are important for absorption of fat soluble vitamins?
bile, pancreatic enzymes
List fat malabsorption syndromes.
inflammatory bowel disease
gastric bypass surgery
Also: use of bile acids or mineral oil
T/F- vitamin A is a name given to a group of related compounds, some of which act as hormones
true (retinol, retinal, retinoic acid)
Name dietary sources of vit A
animal: liver, fish, eggs, milk
plant (carotenoids): 6-carotene, yellow/green vegetables
where is B-carotene converted to retinol?
Where are more than 90% of vitamin A reserves?
Name 4 biological roles of vitamin A
-cell growth/differentiation (epithelial/keratin)
-metabolic effects of retinoids (bind to nuclear hormone receptors)
-Resistance to infection (mucocilliary/intestinal tract cell differentiation and retinoid immune effects)
Earliest manifestation of vitamin A deficiency?
reduced night vision
Five effects of chronic vitamin A deficiency?
-xeropthalmia (dry eye)
-bitot spots (keratin deposits)
-keratomalacia (drying/clouding of cornea)
Name 3 therapeutic uses of retinoids
-acute promyelocytic leukemia
T/F- retinoids aren't teratogens
FAlse. They are! also restrictions on donating blood when taking these because of possibility of getting into a pregnant woman.
What is the most common fat-soluble vitamin poisoning in the united states?
Symptoms of vitamin A poisoning?
Chronic excessive vitamin A results in bone resorption and fractures. T/F
T/F- vit D only affects a limited number of organ systems
False, it affects nearly every organ system
What receptor does it D act on?
vitamin D receptor (nuclear hormone receptor)
Where does vitamin D2 (ergocalciferol) come from?
-plants, fungi, invertebrates
where does vitamin D3 (cholecalciferol) come from?
endogenous vitamin D in animals
What is the main storage form of vitamin D and is best for assessing vitamin D nutritional status?
25-hydroxyvitamin D (calcidiol)
What is the most biologically active form of vitamin D?
1,25 dihydroxyvitamin D (calcitriol)
T/F- calcitriol controls expresssion of 200 genes, is expressed in the brain, prostate, breast, colon and other tissues, and some cancers can convert calcidiol to calcitriol
T/F- vitamin D cannot be used for psoriasis or auto-immune diseases
False, it can be
What role does sunlight play in endogenous synthesis of vit D?
UVB converts 7-dehydrocholesterol to previtamin D3, which rapidly converts to D3.
Not active if UV index less than 3
Can you get vit D toxicity from too much sun?
no, excess previtamin D3 destroyed by sunlight
What are some exogenous sources of vitamin D?
oily fish, eggs, milk, dietary supplements
Where is vitamin D metabolized to 25-OH?