Chapter 7: Fat-soluble vitamins Flashcards
biofortified
adding a nutrient to a food product
deficiency in vitamin A
Could reduce blindness and mortality of children
organic compounds
Contain both carbon-carbon and carbon-hydrogen bonds
T or F: vitamins is a source of energy
False
T or F: vitamins can be used to extract energy from macronutrients, i.e. be used to energy production
True
bioavailability
Degree to which nutrients can be absorbed and used by the body
Ability to disperse or dissolve in water or lipids
/classification
Fat-soluble
Vitamins A, D, E, and K
Water-soluble
B vitamins, choline, and vitamin C
functions of fat soluble vitamins
Vitamin A: Vision and cell differentiation
Vitamin D: bone growth and maintenance
Vitamin E: Antioxidant (protect against cellular damage-neutralize molecule Free radicals)
Vitamin K: blood clotting
vitamin toxicity is experienced more in what type of vitamin
fat soluble vitamin because it can be stored
2 group of compounds of vitamin A
retinoids and carotenoids
in retinoids we have
Retinal (eyes)
Retinol
retinoic acid
Only ———- present in significant amounts in our diet
retinol
preformed vitamin A
retinol in an active form in foods
provitamin
for example, beta-carotene, primary carotenoid in diet, has vitamin activity after conversion to active form in the body
where is retinol stored
liver
what’s the source of vitamin A in plant foods
provitamin A carotenoids
how the conversion of retinoid proceed
retinol and retinal can be converted to each other
and retinal could irreversibly produce retinoic acid
bioavailability of vitamin A
Preformed vitamin A (retinol)
In animal foods and fortified foods
Provitamin A carotenoids
Yellow-, orange-, and red-pigmented fruits and vegetables
what could improve bioavailability of carotenoids
Slicing, chopping, juicing, and cooking
what’s bioavailability
the ability of of our body the absorbed nutrients from a food
Functions of Vitamin A
Vision
Functions as hormone in: Cell development, Immune function, Growth, Bone health, Reproduction
rhodopsin is a pigment composed of
protein opsin and retinal
why is vitamin A (retinal) important for light detection
opsin and cis-retinal are important component for the formation of rhodopsin which allows to process light sources supporting normal vision
what are free radicals
Free radicals are reactive molecules with unpaired electrons that try to pair up with other molecules, atoms, or electrons.
At high levels, they damage cells, including DNA, through a process called oxidation
vitamin is an Antioxidant: T or F
TRUE
how a free radical “damage” a molecule
steals an electron from it to stabilize itself
the role of vitamin A as an antioxidant…
provide an electron to a free radical without destabilizing itself
how can we beat free radicals
eating a plant-rich diet that contains beta-carotene and other antioxidants may reduce the risk of those diseases.
ch 17
disease of vitamin A deficiency
compromised vision and Impaired immunity,
disease of vitamin A toxicity
Hypervitaminosis A
Usually results from excess supplementation
Weaknesses or defects in bones
Can lead to osteoporosis or fractures
Can cause birth defects
Beta-carotene only makes skin yellow or orange
UL for adults
3000 mcg RAE
what is vitamin D known as
“Sunshine vitamin”
how can body produce vitamin D
With UV light exposure, can be produced from cholesterol in the skin
where should Vitamin D should be activated to fulfill is biological functions in the body
the kidneys and liver
Functions of Vitamin D
!!Helps bone growth and maintenance
Regulates calcium metabolism (calcium homeostasis)!!
Blood levels, absorption, excretion
Regulates protein synthesis
Possibly regulates cardiovascular function
the formal term for active form of vitamin D is
calcitriol
what are the three mechanisms that calcitriol use to maintain calcium homeostasis
- calcitriol signals the kidney to take calcium from the urine or make it available for circulation
- calcitriol could increase calcium release from bone to circulatory space
- calcitriol increases absorption of calcium from the intestines
groups at risk for Vitamin D deficiency
Those who avoid vitamin-D fortified dairy foods
People with dark skin
Little sun exposure or use sunscreen (blocks UV rays and prevents vitamin D synthesis)
Exclusively breast-fed infants (not a rich source of vitamin D)
Elderly
Reduced ability to synthesize vitamin D
Reduced sun exposure
vitamin D deficiency
May increase risk of:
Rickets (in children)
Osteomalacia (in adults)
Vitamin D Toxicity
Hypervitaminosis D
Likely result of excess supplementation
Symptoms may include:
Loss of appetite
Weight loss
Irregular heartbeat
Frequent urination
Increased calcium levels in the blood
Functions of Vitamin E (tocopherols)
Antioxidant protecting against oxidative damage; it is Incorporated into cell membranes
In LDLs that would otherwise increase plaque forming potential
In white blood cells, thus maintaining healthy immune function)
how vitamin E aid in phospholipid bilayer
imbedded in phospholipid bilayer, it neutralizes free radicals and breaks the chain of oxidative damage
T or F: vitamin E is the most toxic out of the fat-soluble vitamins
FALSE
Functions of Vitamin K
Needed for synthesis of proteins for blood clotting
(Deficiency can cause uncontrolled bleeding)
Bone metabolism
(Modifies bone proteins)
Vitamin K Deficiency and Toxicity
Deficiency can cause hemorrhaging
No evidence of toxicity at any level
preformed
already active
the majority of intake for vitamin D is
via dietary intake
out of every vitamin with could have a risk of causing toxicity and which is less probable of causing toxicity
vitamin A
vitamin K
