Fat Soluble Vitamins Flashcards
describe the physiology of Fat soluble vitamins:
.
- accumulated “stores” in body;
- require absorption of dietary fat and a carrier system for transport in blood;
- potential for toxicity with excessive intake
what are 6 Situations that place a patient at risk for micronutrient deficiency
- Primary inadequate food intake and/or inadequate variety, esp w/ monotonous diet
- Increased nutrient requirements unmet by food selections
- Increased metabolic demands
- Maldigestion & malabsorption
- Drug-nutrient or medical treatment-nutrient interactions
- “Requirements” for pharmacologic doses (interactions
what is the function of vitamin A
essential in photochemical basis of vision (signals in retina to brain visual cortex); maintenance of conjunctival membranes & cornea; critical for epithelial cellular differentiation and proliferation
Preformed retinyl palmitate (vitamin A) can be consumed from these animal sources
Liver, dairy, egg yolk, fish oil
the Precursor to vitamin A, Beta-carotene can come from these food sources
Deep yellow and green vegetables
Spinach, carrots, broccoli, pumpkin
vitamin A deficiency can cause ______
EYES: xerophthalmia (corneal dryness) Bitot’s Spots, night blindness total blindness
EPITHELIUM:
linings flat, dry,
and keratinized
Vitamin A deficiency can lead to Immune deficiency which is _____
dysregulation of immune response; effect depends on infectious agent & type of immune response it elicits;
supplementation to correct Vit A deficiency that causes immune deficiency in patients can ______
↓’s child mortality by 23-34%
what are Risks for Vit A deficiency:
1) low intake &/or low fat intake (fat < 5% of kcal);
2) fat malabsorption (liver disease & low bile salts; pancreatic insufficiency);
3) protein energy malnutrition
what are the sx’s of Toxicity from Vit A (only w/ preformed Vit A retinol, dose dependent) ex: cod liver oil consumption.
(You can’t get toxicity from beta carotene)
vomiting, increased intracranial pressure, headache, bone pain (periosteal proliferation), bone mineral loss (↑ fractures & ↑ osteoporosis), liver damage (hepatitis, fibrosis, liver failure), death; birth defects
what lab testing can you do for Vit A.
serum retinol (but levels remain WNL until liver stores nearly exhausted & ↓ w/ Acute Phase Reaction)
what are the functions of Vitamin D
Functions as a hormone; maintains intracellular & extracellular Ca++ w/in physiologic range; stimulates intestinal absorption Ca++and P, renal reabsorption of Ca++ and P, mobilization of Ca++ and P from bone; innate immune function (generation of toxic radicals), cellular growth and differentiation through nuclear and plasma membrane vitamin D receptors present in many types of cells,
the precursor to vitamin is in the skin and is called ________, it gets converted to cholecalciferol (Vit D3) by UV light
dehydrocholesterol
Dietary sources of vitamin D are :
a) Natural: fish liver oils, fatty fish, egg yolks;
b) fortified milk & formulas
D3 comes from ______ sources, D2 ergocalciferol from ______ sources; D3 activity 2-3x > D2
animal,
plant (algae)
Describe the metabolism of Vitamin D
Absorbed via chylomicrons; Vitamin D2 or D3 hydroxylated in liver, to 25-hydroxy-cholecalciferol and then in kidney to 1,25-dihydroxy-cholecalciferol (calcitriol) = active form
what are the definitions of Vitamin D deficiency, insufficiency and sufficiency?
Deficient: 25OH-D <20 ng/mL (<50nmol/L)
Insufficient: 21-29 ng/mL (50-80 nmol/L)
Sufficient: >/= 30 ng/mL (>80 nmol/L)
what can vitamin D deficiency cause in children
Rickets: (25OH-D <11ng/mL) failure of maturation of cartilage and calcification; “rachitic rosary” on ribs, bowed legs, widened metaphyses (esp at wrist), painful bones, fractures;
what can vitamin D deficiency cause in adults
osteopenia/osteoperosis
what are some Emerging Associations with Vit D insufficiency or deficiency (mostly epidemiological studies)
Autoimmune Disorders (e.g. MS) Neuromuscular function Cardiovascular Disease Cancer incidence Overall Mortality
what are risk factors for developing Vit D deficiency
Low Sun exposure (NE winter) Dark Pigmentation Low dietary intake Fat Malabsorption Breastfed Infant (Needs supplement) Obesity Fat sequestration, sedentary Liver or Renal Disease (X-OH) (Need Calcitriol Rx supplementation)
what are the vitamin D supplementation recommendations in breast fed infants
400IU D3 per day by 2 months,
Until 500ml/d (>16oz) formula or milk
Or formula fed taking <500ml/day
what is RDA of Vit D for children
600 IU/d
what is the Institute of Medicine recommendation for Vit D supplements in adults 18-70yrs
600IU per day
what are the clinical and lab findings for Vit D toxicity
Lab: Hypercalcemia
Clinical: Vomiting, seizures, nephrocalcinosis, vascular and soft tissue calcinosis
what are risk factors for Vit d toxicity
Sarcoidosis (granulomas activate D)
>10,000 IU/d for wks in child or during pregnancy
50-100,000 IU daily in adult >3wks
what is the Function of vitamin E
Antioxidant, scavenges free radicals, stabilizes cell membranes
what are the Sources of Vitamin E
Polyunsaturated fat rich vegetable oils (e.g. sunflower), corn, nuts, wheat germ
Clinical presentation of Vitamin E deficiency
1) Neurologic Degeneration IRREVERSIBLE
Loss of reflexes (DTRs)
Loss of coordination
Loss of vibration and position sense
Spinocerebellar ataxia
Neuropathy
Ophthalmoplegia (paralysis or weakness of the eye muscles)
2) Hemolytic Anemiawhat are risks for developing Vit E deficiency
malnurishment
prematurity
fat malbsorption /short gut
Vit E toxicity can cause _________
Coagulopathy
Very large doses inhibit Vit K dependent clotting factors
what is the Function of Vit K
carboxylation of clotting factor proteins (II prothrombin, VII, IX, X)
what are the Sources of Vit K
Diet: leafy greens, brocolli, fruits, seeds, beef liver
Synthesis by Intestinal Bacteria
what are the findings of Vit K deficiency
prolonged coagulation time
Hemorrhagic disease of the newborn (Purpura, GI bleeds, CNS bleeds)
what are the Risk factors for developing Vit K deficiency
Newborns – poor placental transport
2-12 wks breastfed untreated
Fat Malabsorption
Chronic Antibiotics
what is the Prevention methods for Vit K defiency
all Newborns 0.5-1.0mg IM once
Adequate oral dosing has not been defined
