Fat soluble Viatmins SG Flashcards
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
- fruits
- veggies
- fats
- oils
- sweets
- fortified foods such as cerials and supps
what regulates the cleavage of the three provitamin A carotenoids
-wehre?
- vitamin A stores regulate the cleavage
- happens in the enterocyte
functions of vitamin A metabolites
- vision
- cell division and differentiation
- reproduction
- immunity
- 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
- alopecia
- teratogenicity
- osteoperosis
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
-cholecalciferol
vitamin D synthesis
-in the skin in response to sun light
ergocalciferol
-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
-antioxidant
deficiency can occur with
- poor intake
- GI disesae
- malabsorption
- 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
