Fat Soluble Vitamins Flashcards
Vitamins
-an organic compound required as a nutrient in tiny amounts by an organism
Vitamins cannot be synthesized in sufficient quantities by an organism, and
must be obtained from the diet
Name 4 functions of vitamins
- hormone like functions as regulators of mineral metabolism (vit.D)
- regulators of cell and tissue growth and differentiation (some forms of vit. A)
- antioxidants (vit. E, C)
- enzyme cofactors (tightly bound to enzyme as a part of prosthetic group, coenzymes)
How are vitamins classified?
fat soluble and water soluble
What are fat-soluble vitamins?
hydrophobic compounds, absorbed efficiently with lipids
Fat-soluble vitamins function
transport in the blood in lipoproteins more likely to accumulate in the body
Examples of fat soluble vitamins
A, D, E, and K
Where are fat soluble vitamins stored? How long are they stored for?
- stored in the liver and adipose tissues
- fat soluble vitamins except for vitamin K, are stored for long periods of time
Toxic levels of fat soluble vitamins lead to
hypervitaminosis
Water soluble vitamins are
8 B vitamins and vitamin C
Water soluble vitamins
function
function as enzyme cofactors
Hydrophilic compounds dissolve …………….
easily in water
Water soluble vitamins are:
- not readily stored, excreted from the body
- their consistent daily intake is important
Many types of water-soluble vitamins are synthesized by
bacteria
Vitamin A is also called
Biologically active forms are:
retinol
retinoids: retinol, retinal, retinoic acid
Major vitamin A precursors (provitamins) are
plants carotenoids
Food originating from animals contain vitamin A in the form of
esters-retinol and long fatty acid
Vitamin A in foods:
retinyl esters (in animal food) beta-carotene (in plant food)
Vitamin A in the body
retinol (supports reproduction)
retinal (participates in vision)
retinoic acid (regulates growth)
Functions of vitamin A include
- vision
- immune function
- bone metabolism
- haematopoieis
- skin health
Vitamin A can be found from certain foods such as
egg yolk whole milk butter carrots squash meat fish
Vitamin A deficiency and toxicity
night blindness
blindness
hypovitaminoisis A
Vitamin D is also known as
calciferol, 1,25-dihydroxy
vitamin D3 or cholecalciferol (in animals)
vitamin D2 or ergocalciferol (in plants)
Vitamin D is a nonessential nutrient that acts
like a hormone in the body
The body can make vitamin D with help from _________, once vitamins enter the body, it must become _____
sunlight
activated (in the liver and kidneys)
Functions of vitamin D
- transported in the blood on a carrier (VDBP, vitamin D binding protein)
- 1,25(OH)2D binds to intracellular receptors (intestine, bone, kidney)
- the main function is to maintain plasma levels of calcium and phosphate levels
Vitamin D deficiency and toxicity
rickets (softening and/or weakening of bones in children)
osteomalacia (in adults)
toxicity disease is called hypervitaminosis D
What is a symptom of vitamin D toxicity?
elevated blood calcium
Sources of vitamin D are
- sun-soaked mushrooms
- eggs
- oily fish
- fortified milk
- sunshine
Vitamin E is a family of
a-, B-, y-, S- tocopherols
Only the alpha-tocopherol has vitamin E activity in
human beings
Function of vitamin E
is an antioxidant (compounds that inhibit oxidation)
Good sources of vitamin E are
nuts & seeds - almonds wheat germ dark green-leafy vegetables like asparagus & spinach sunflower seeds groundnut oil
Vitamin E deficiency is
rare
Vitamin E deficiency and toxicity
Provide symptoms as well
erythrocyte hemolysis symptoms include -loss of muscle reflexes -impaired vision and speech -nerve damage toxicity is relatively small
Vitamin K is
a group of lipophilic, hydrophobic vitamins
Vitamin K is met through
the action of intestinal bacteria
Vitamin K is essential in
blood clotting
Vitamin K deficiencies can occur
in newborn infants
Sources of vitamin K include
spinach
asparagus
broccoli
Functions of vitamin K include:
- synthesis of blood-clotting proteins and bone proteins
- important for healing
Why is vitamin K given during surgery?
to reduce bleeding
Vitamin K-deficiency
- caused by fat malabsorption
- blood clotting disorders
- osteoporosis
- there is no shortage, vitamin K is abundant in the diet
Vitamin K sources include
- spinach
- asparagus
- broccoli
- beans
- soybeans
- eggs
- strawberries
- meat
- fish oils
