Chapter 11: Nutrients involved in Antioxidant Function Flashcards Preview

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What're the three main vitamins used as an antioxidant

vit C, A, E


How do antioxidants fight free radicals?

by stabilizing free radicals by giving or withdrawing their excess charge


Is vitamin C water or fat soluble?

water soluble.


T/F Vitamin C gets destroyed by oxygen, light, heat, or metal contact?



Why is a vitamin C supplement good for someone with anemia?

because it facilitates iron absorption


Name the general mechanism for vitamin C reformation?

vitamin C gets oxidized by a free radical that takes its electrons, and gets converted into dehydroascorbic acids. It then gets regenerated to ascorbic acid/normal vit C when electrons and protons are provided by other antioxidants.


Why is vitamin C needed to prevent scurvy? A tissue degrading condition

vitamin C is needed in collagen production. No vit C = weaker collagen fibers because a certain component cannot be made


The RDA for vitamin C is___

90mg/day for men, 75mg/day for women.


What is a sign of vitamin C toxicity?

difficult to be toxic because it is a water soluble compound and can be peed out, but it may facilitate kidney stones and cause tooth erosion


What're the two main forms of vitamin A found in the diet?

1) provitamines: vitamin A precursors such as carotenoids.
2) retinoids: retinol, retinoic acid.


Retinol vs retinoic acid?

retinol is involved with vision, sexual reproductwhichion, bone health and immune function.

Retinoic acid is involved in cell differentiation, bone health and immune and gene expression.


Purpose of retinol binding protein?

helps circulate vitamin A through the blood


What is rhodopsin?

a complex formed by retinal and the opsin protein.


How does rhodopsin aid in vision? if there is a vitamin A deficiency, how may this affect a person's eye sight?

rhodopsin undergoes conformational change from trans to cis, triggering a nerve impulse, and the retinal and opsin protein breaks apart. If there is a vitamin A deficiency, the broken rhodopsin cannot be regenerated, and until it is reformed by the presence of retinal, light cannot be received.


which type of vitamin A is needed for cell differentiation and epigenetcis?

retinoic acid.


how does a deficiency in retinoic acid affect the eyes in terms of epithelial tissue differentiation?

because retinoic acid affects cell differentiation, a deficiency can cause the epithelial cells in the eyes to produce keratin instead of mucus. This causes cornea to dry up and cause blindness.


Two types of eye conditions caused by vitamin A deficiency

1) xerophthalmia: progressive eye disorder starting with night blindness
2) keratomalacia: cloudiness and softening of the cornea, cornea ruptures and causes permanent blindness.


Why does lack of vitamin A cause fetal development abnormalities?

because vitamin A plays a roll in cell differentiation.


why does lack of vitamin A cause increased infection risk?

because vitamin A effects epithelial cell differentiation, and epithelial cells are an important immune defense component


what is hypercarotenemia

causes hyperpigmentation from eating too many foods with provitamins (vit A precursors) like carrots, because they contain a lot of cartenoids


If vitamin E fat soluble or water soluble

fat soluble


What does vitamin E do?

protect against oxidative damage, like all antioxadents, also protects polyunsaturated fatty acids from oxidation in the cell membranes


how can one increase the amount of vitamin E in their diet?

eating a lot of polyunsaturated fat, such as in avocados or nuts or canola oil


what cell types are more susceptible to degradation if there is not enough vitamin E?

nerve cells- sheath is made of fat with vitamin E. not enough vitamin E can cause degradation and thus weakness and lack of coordination

RBCs- can cause cells to rupture


Which two groups of individuals are at risk for a vitmin E deficiency?

1) cystic fibrosis people. they have impaired fat absorption mechanisms and therefor cannot obtain much of the fat soluble vitamins.
2) premature infants; there was not enough vitamin E transferred from mom to baby.