Flashcards in Wk1 Fat soluble vit/minerals/elect pt 1 Deck (47)
Define EAR (Estimated Average Requirement)
Average daily nutrient intake level estimated to meet the requirements of of half of the healthy members of a particular life stage and gender group
Define RDA (Recommended Daily Allowance)
Average daily dietary nutrient intake level sufficient to meet the nutritional requirements of nearly all (97-98%) healthy persons in a particular life stage and gender group
Define Tolerable Upper Limit:
Risk of "overdose" is approx. 0.1%
Biologically active form of vit A:
-branched polyunsaturated acyle chain
Three things all-trans-retinol can be converted to:
2. carboxylic acid
3. ester w/ fatty acid (eg. palmitate)
Three dietary forms of vit A:
1. retinyl palmitate
Vit A metabolite that can be transported in blood with albumin:
Vit A metabolites that are transported in chylomicrons:
Retinyl-fatty acid esters
Reservoir for vit A storage in liver:
retinal cycle in photoreceptors?
cis-retinal + opsin = rhodopsin
rhodopsin + UV light = opsin + tras-retinal
trans-retinal --> G-protein rec. --> closes Na+ channels --> hyperpolarization of rod cell --> signals neuron
trans-retinal recycled back to cis-retinal
4 roles of retinoic acid ligand based transcription factors (RAR, RXR, PPAR):
1. differentiation of goblet cells (inhibits keratinization)
2. apoptosis of cancer cells
3. maturation of dendritic cells
4. recruitment of antibody secreting cells to small intestine
Vit A metabolites that act as antioxidants:
carotenes (double bonds bind free radicals)
Bitot's spots in the eye?
Vit A deficiency
Dry eye due to keratinization?
due to vit A deficiency
Vit E form with SATURATED 16-C acyl chains:
Vit E form with polyUNsaturated 16-C acyl chains:
Vit E absorption and distribution parallels _____?
fat digestion and absorption
Vit E functions?
1. lipid bilayers
2. intracellular plasma membranes
3. cellular oxidative stress defense
Vit that can inhibit Vit K absorption and metabolism:
Vit E deficiency: Causes? Symptoms?
-short bowel syndrome
-ataxia, loss of vibratory sense
Main form of dietary vit K:
green leafy vegetables
Vit K produced by fermentation:
Vit K absorption paralells _____.
Vit K stored in _______.
cell membranes of lung, kidney, bone marrow, adrenal glands
Coumadin blocks what enzyme?
vit k epoxide reductase
Clotting factors reliant on vit K dependent carboxylation:
Main circulating form of vit D:
Biologically active form of vit D:
Where does vit D get activated:
**in response to PTH