Chapter 12: Fat-soluble vitamins Flashcards
What are the 2 classes of vitamins?
1) water soluble
2) fat soluble
Examples of water-soluble vitamins
Vitamin B complex and C
Examples of fat-soluble vitamins
Vitamins A, D, E, and K
How much of fat-soluble vitamins are absorbed?
40-90%
How much of water-soluble vitamins are absorbed?
90+%
Where does the digestive process start for ALL vitamins?
The stomach, the release of vitamins from food occurs
What aids the stomach in release of ALL vitamins from food?
Digestive enzymes produced by the pancreas
Where are ALL vitamins absorbed?
Small intestine
What aids the small intestine in fat-soluble vitamin absorption?
Bile produced in the liver (stored in gall bladder)
What else is absorbed during fat-soluble vitamin digestion?
dietary fat (along with the vitamins) are carried by the chylomicrons into the lymphatic circulations
Where in the body is vitamin K produced?
Made by bacteria in the ileum of the small intestine and large intestine
What is the transport of vitamins based on?
Solubility
How are water soluble vitamins transported?
Into the portal vein
Where are fat-soluble vitamins stored in the body?
In fat (adipose of liver)
Are water soluble vitamins stored?
It is very limited except for B-6 and B12
What vitamins can be toxic in very high doses?
A and D
What are retinoids?
active form of vit A
3 forms of retinoids:
Retinal, retinol, and retinoic acid
Dietary sources of retinoids:
liver, fish oils, fortified dairy products and eggs
What are caroteinoids?
Provitamins which can be converted to Vit A
Most common caroteinoid?
Beta-carotene
Dietary sources of caroteinoids:
dark green and yellow-orange vegetables and fruit
Where is most vitamin A stored in your body?
liver ~90%
Which has lower absorption: carotenoids or retinoids?
carotenoid
6 functions of vitamin A:
Growth and development, cell differentiation/signaling, vision, immune function, dermatology, antioxidents
Vitamin A deficiencies can lead to:
blindness, night blindness, xerophthalmia, follicular hyperkeratosis
Are carotenoids toxic?
no
3 types of vitamin A toxicities:
acute, chronic, teratogenic
Is vitamin D necessary?
Conditionally, not always
What type of hormone in vitamin D?
prohormone (precursor to active hormone)
Dietary sources of vitamin D
fatty fish, cod liver oil, fortified dairy products and breakfast cereals
Does vitamin D follow AI or RDA standards?
AI (15 ug for adults)
WHAT absorbs vitamin D?
chylomicrons
What carries vitamin D?
Proteins in blood
Where is vitamin D stored?
adipose (mostly) and liver
how is vitamin D excreated?
bile or urine
What regulates vitamin D metabolism?
parathyroid hormone (PTH)
Functions of vitamin D
Calcium and phosphorus homeostasis, bone health, immune function, cancer?
What does a deficiency in vitamin D cause in kids and in adults (2 diff things)
Kids- rickets
Adults- osteomalacia
upper limit of vitamin D intake
100ug (toxic)
Dietary sources of vitamin E:
plant oils, wheat germ, asparagus, almonds, peanuts, and sunflower seeds
RDA of vit E:
15 mg
How is vitamin E transported?
via chylomicrons from intestine (does not have a specific carrier protein in blood
How is vitamin E excreted?
bile, urine, and skin
Vitamin E functions:
antioxidant
Effects of vitamin E deficiencies
hemolytic anemia
