Card Set Information
nutritional biochemistry Carotenoids
What is the major cause of visual loss and irreversible blindness among elderly?
Age-related macular degeneration. macula lutea aka yellow spot is the area of maximal visual acuity and its yellow color is due to lutein and zeaxanthin
Why do plants make carotenoids?
to protect from oxidative stress from the UV light. Supplemental beta-carotene yeild at best SPF of 4
Lycopene is how much better than beta-carotene and Vitamin E
it is 2 times better than beta-carotene, and 10 times better that vitamin E.
Lycopene and Lutein work together which have a better efffectiveness than any other carotenods by itself
What are the three majo functions of carotenoids?
1. they are present in the interior of the phospholipid membrans of all cells and lipoprotein
2. possess an extended system of conjugated double bonds that enables them to quench singlet molecular oxygen and peroxyl radicals
3. decrease in order of free radical scavenging ability
Individuals with high serum carotenoids have a lower incidence of what?
Cardiovascular disease, cancer, cataracts and age-related macular degeneration and diabetic retinopathies
Where does Lutein and zeaxanthin accumulate?
In the macular region of the retina
Where are carotenoids stored?
Mainly in the liver and adipose tissues but some specific tissues concentrate specific carotenoids
How are carotenoids taken up by the tissues?
as a pat of the lipoprotein through receptor mediated endocytosis
Serum Carotenoids concentrations reflect
It only reflect recent intake and not body's stores
What are the most common carotenoids?
Alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin and cryptoxanthin
In the serum, how are carotenoids transported
using VLDL, LDL, and HDL
Once the Carotenoids reach the liver what are the 3 metabolic routes it can take?
1. cleaved and reduced to form retinol
2. packaged and released from the liver in VLDL's
3. stored in the livers's stellate cells
When comparing organic and conventional farming methods which has the better effect on carotenoids?
The agriculture chosen does NOT have any effect on carotenoid content, antioxidant capacity, or bioavailability of the carotenoids
supplemental Beta-Carotene in and "oil-diet" will increase what?
Serum Retinol concentrations by 3 times
How is Beta-Carotene transported once it leaves the intestine
It leave the intestine intact for transport by Chylomicrons to tissues
Beta-Carotene 15, 15-monoxygenase has a low affinity for what 3 carotenoids?
it has a low affinity for beta-carotene, 60% is hydrolyzed, and the enzyme has an even lower affinity for alpha-carotene and beta-cryptoxanthine
What suppresses transcription expression when retinoid concentrations are too high?
Beta-carotene 15,15-monoxygenase, therefore high doses of beta-carotene supplementation does not cause any signs of hypervitaminosis A or teratogenicity
Retinal Oxidase breaks retinal down to what?
Retinoic Acid(carboxylic Acid)
Retinal Reductase and NADPH reduce retinal to what?
Beta-Carotene 15,15-monooxygenase breaks beta-carotene down to what?
2 Moles of Retinal
What percentage does provitamin A Carotenoids contribute to the body's supply of retinol
What protects Carotenoids from oxidation? and what in excess can diminish carotenoid absorbtion?
What inhibts Carotenoids from being absorbed?
How are dietary carotenoids absorbed
By Passive Diffusion
How many eggs a day will increase serum lutein and zeaxanthin concentrations without altering the lipids and lipoprotein cholesterol concentrations?
Eggs are rich in what?
Lutein, and zeaxanthin
Beets and Kiwi fruit are a good source of what?
Corn, yellow and orange bell peppers are a good source of ?
Oranges, tangerines, and red bell peppers provide much of the dietary
Tomatoes are a source of what?
Carrots are a major source of what
Alpha-carotene and Beta Carotene
How many Carotenoids can be converted to Retinol
What are the Carotenoids that are NOT Vitamin A precursors, but physiologically important
Lutein,Zeaxanthine, Canthaxanthine, and Lycopene
What are the 3 carotenoids that are precursors of retinol
Alpha-Carotene, Beta-carotene and Beta-Cryptoxanthine
What are the toxic effect of carotenoids?
hypercarotenemia is caused b consuming 30 mg/day
it causes a yellow/orange discoloration of the skin
Where are carotenoids excreted?
in feces via bile
What are the 3 immune fucntions of Beta-carotene?
1. increase the number of lymphocytes
2. enhanced natural killer cell cytotoxicity
3. stimulated neutrophil phagocytic and bacterial killing ability.
an antimetastatic effect through up-reuglation of an antimetastaic gene named Nm23-H1, and inhibit angiogenesis by indhibiting the express of VEGF
anti-apoptosis genes Bcl-2 and Bcl-xl expression and activiating the pro-apoptosis gene BAX, caspase-3 and p53 expression
Canthanxanthin are effective in inhibiting what?
Neoplastic transformation than beta-carotene, alpha-carotene and lycopene
what are the afects of carotenoids on cell proliferation,growth and differentiation
inhibits cancer cell growth by stimulating apoptosis
High dietary intake of tomatoe products can have effect on
arthero-protective effects, reduce LDL cholesterol levels and increase LDL resistance to oxidation in healthy adults. howevr supplementations alone have not been established.