Fat soluble Viatmins SG Flashcards Preview

Nutrition > Fat soluble Viatmins SG > Flashcards

Flashcards in Fat soluble Viatmins SG Deck (31):

preformed vitamin A appears where

-retinyl esters or retinol
-found in animal foods such as liver, fish, dairy,
-also in fortified foods such as cerials and reduced fat milk


carotenoids are found in

-fortified foods such as cerials and supps


what regulates the cleavage of the three provitamin A carotenoids

-vitamin A stores regulate the cleavage
-happens in the enterocyte


functions of vitamin A metabolites

-cell division and differentiation
-bone growth


vit A def's occur with

-poor diet
-malabsorptive disorders
-parasite infestation


signs of a Vitamin A def

-impaired night vision and epithelial scarring of the eyes leading to blindness
-impaired growth and development
-impaired immunity and increased risk of infections


vitamin A tox
-when does it occur?

-excess ingestion of preformed vitamin A
-impaired excretion of vitamin metabolites
-excess intake is almost always due to supplements
-excretion may be impaired in chronic kidney disease, this causes a predisposition of vitamin A def


vitamin A tox is usually through chronic overload and this manifests by

-headache, diziness, loss of muscle coordination and eventual coma
-liver damage and eventual cirrhosis


provitamin A carotenoids and tox

-they do not result in tox becasue cleavage to vitamin A is regulated
-increaed provitamin results in excess oraange or yellow pigmentation of skin


supplementation with beta carotene

-not recommended due to supp trials where some populations such as smokers experienced greater rates of cancer


fancy name for viatmin D



vitamin D synthesis

-in the skin in response to sun light



-not endogenously synthesized but is consumed from some plant food sources as well as in supps and fortified foods


hydroxylation of vitamin D

-occurs in the liver and then in the kidney to produce the active form 25-(OH)2


vitamin D functions to

-increase calcium and phosphate absorption in the small intestine
-increase calcium resorption and increase phosphate excretion by the kidney
-increase calcium resorption as well as deposition in bone


risks for vitamin D deficiency include

-infants who are exclusively breast fed
-poor diet
-inadequate sun exposure
-darker pigmentation of skin
-lactose intolerance, as milk products may be an important source for some individuals
-fat metabolism
-liver disease
-kidney disease


vitamin D deficiency syndromes

-children: rickets is manifested byimparied bone mineralization and bowing of the legs
-adults: osteomalacia is manifested by bone pain and tenderness
-acceleration of osteoporosis and fracture risk
-myopathy and weakness


when does vitamin D tox occur

-medications or dietary supplememnts containing vitamin D
-skin synthesis is suppressed with vitamin D sufficiency
-manifests by hypercalciemia sequale


vitamin D upper limit is based on

-risk of hypercalcemia and its complications of hypercalciuria nephrolithiasis and clacification of vascular and soft tissue


vitamin e functions as an



deficiency can occur with

-poor intake
-GI disesae
-congenital diseases which prevent vitamin E export from the liver (disorders of lipid metabolism where vitamin E can not be carried by lipoproteins or due to genetic defects in alpha-tocopherol transfer proteins)


def in vitamin E most commonly results in

-peripheral neuropathy
-can also result in: immune defects, optic neuropathy, and hemolytic anemia


toxicity is due to

-use of dietary supps


tox of vitamin E results in

-increased risk of hemorrhage, and this serves as the rationale for the upper limit
-patients taking vitamin E supplements should stop then before surgery


all cause mortality limit of vitamin E

-400IU per day
-routine supp at or above this limit is not recommended


wehre is vitamin K found

-green leafy plants
-soy beans
-some dairy
-some animal foods
-some fermented foods
-fortified foods such as breakfast cereals
-fast food rich in plant oils


role of vitamin K

-cofactor for the gama-carboxylation of glutamic acid residues to from Gla
-this carboxylation is necessary for functionality by allowing calcium binding of the vitmain K dependent blood coagulation factors


purpose of the vitamin K cycle

-once it is used in gama carboxylation, it is in the form of an epoxide that needs to be regenerated by the vitamin K cycle


action of warfarin

-blocks the regeneration of vitamin K by inhibiting the vitamin K cycle


risk for vitamin K deficiency occurs with

-malabsorptive disorders
-liver disease, which can influence absorption and storage
-poor diet and alcoholism
-birth, babies are born vitamin K deficient


deficiency in vitamin K results in risk for

-abnormal bleeding
-hemorrhagic disease in newborns who are not supplemented with vitmain K
-embryopathy, or congenital syndromes in children born to women who take warfarin during pregnancy or more rapidly in children that are born to women with vitamin K def