Fat Soluble Flashcards
Vitamin A structure
Retinol, retinal, retinoic acid, and retinyl esters
What are provitamin A?
carotenoids and Beta-carotene
Vitamin A animal source form
retinyl ester
Vitamin A retinyl ester sources
Liver
Fish liver oil
Egg yolk
Margarine/butter
Fortified milk
Vitamin A plant source form
provitamin A
Vitamin A carotenoid sources
Deep orange/yellow fruits and vegetables, dark leafy greens, broccoli
Vitamin A functions 7
- Vision
- Cell differentiation
- Growth
- Antioxidant
- Immune Function
- Bone growth
- Reproductive systems
Vitamin A role in vision
vitamin A is used to produce rhodopsin which allows for the detection of light
Vitamin A role in cell differentiation
through effects on gene expression
Vitamin A role in growth
stimulated by retinoic acid
Vitamin A role in antioxidant
carotenoids are involved decreasing oxidative stress; may decrease heart disease/cancer risk
What is rhodopsin
rhodopsin is found in the rods’ disks made up of retinal and opsin
What populations are at risk for vitamin A deficiency?
- Fat malabsorption
- Alcoholism
- Zinc deficiency
vitamin A toxicity symptoms
- Anorexia
- Skin discomfort
- Alopecia
- headache
Explain the rhodopsin cycle
light hits the retina on the back of the eye, rhodopsin in the rods cells is transformed and signals sent to brain, rhosopsin is cleaved into opsin and cis-retinal and conversion of cis-retinal to trans-retinal, tran-retinal is converted back to cis-retinal, cis-retinal reattaches to opsin to reform rhodopsin
Vitamin A deficiency symptoms
- Night blindness
- Bitot’s spot
- Xerophthalmia/keratomalacia
- Poor growth
Explain the vitamin A deficiency and its effect on night blindness
in darkness, after light passes, individual can only see a few few away.
what is bitot’s spots
white spots on eyes
why is zinc deficiency an at risk group for vitamin a deficiency?
vitamin A is important for rRBP that carries vit A
What is alopecia
patches of hairloss
what is HYPERCAROTENOSIS
excess B-carotene associated with yellowing skin
How is Vitamin A assessed
clinical assessment and plasma retinol
What is Vitamin D active form
Vitamin d3/Calcitriol
vitamin D structure
1,25-(OH)2
Vitamin D sources
Fish Liver oil
fatty fish
eggs
liver from beef
butter
fortified juices
milk and margarine
shitake mushrooms
biosynthesis of vitamin D
exposure to sunlight converts 7-dehydrocholesterol to Provitamin D which is converted into cholecalciferol
Vitamin D absorption/transportation/metabolism
absorbed from micelle with lipids, enters circulation via chylomicron, in liver cholecalciferol is converted into 25-OH cholecalciferol is converted via parathyroid hormones into 1,25-(OH)2 cholecalciferol/calcitriol
vitamin D function 4
- calcium absorption
- calcium retention/reabsorption
- calcium mobilization
- cell differentiation
explain vitD role in calcium absorption
low calcium levels stimulate parathyroid hormone, PTH increases production of calcitriol, calcitriol stimulates calcium absorption at the intestine by calbindin
explain vitD role in calcium retention/reabsorption
low calcium levels stimulate calcitriol through PTH which increases renal calcium reabsorption
explain vitD role in calcium mobilization
low calcium levels stimulate calcitriol through PTH which stimulates osteoclasts which inc serum calcium
explain vitD role in cell differentiation
calcitriol may inhibit cancer growth
VitD deèiciency symptoms
children- rickets by bowed legs, knock knees
adults- bone pain, osteomalacia, may play role in osteoporosis
what populations are at risk for vitD deficiency
- fat malabsorption
- infants if remain inside/born in winter
- vegans
- elderly
- renal/liver disease
- dark skin
- obesity
vitD toxicity symptoms
elevated serum calcium, soft tissue calcification, anorexia, nausea
Vit D UL
4,000 IU/day
Vit D assessment
plasma 25-OH cholecalciferol
optimal 30-60ng/mL
Vitamin E name
a-tocopherol
vitE sources
vegetable oils
nuts
leafy greens
almonds
cooked spinach
sunflower seeds
vitE absorption/transport/distribution
absorbed as micelles with other lipids, transported into blood with chylomicrons, delivered to tissues by LDL
VitE functions
- antioxidant-free radicals
- immune system
- growth nucleic acid/protein synthesis
regeneration of vit E
vitamin C, ascorbate, NADPH
Vit E deficiency symptoms
hemolytic anemia- breakage of RBC
2. low birth weight
3. ecreased neurological/immune fucntion
population at risk for vitE deficiency
- fat malabsorption disorders
- infants
- apolipoprotein B deficient
vit E toxicity
high doses may cause
- muscle weakness
- GI distress
- vit K interference
Vit E assessment
- serum tocopherol
- hydrogen peroxide hemolysis text
