Chapter 11: Nutrients involved in Antioxidant Function

Question 1

What’re the three main vitamins used as an antioxidant

Answer 1

vit C, A, E

Question 2

How do antioxidants fight free radicals?

Answer 2

by stabilizing free radicals by giving or withdrawing their excess charge

Question 3

Is vitamin C water or fat soluble?

Answer 3

water soluble.

Question 4

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

Answer 4

true.

Question 5

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

Answer 5

because it facilitates iron absorption

Question 6

Name the general mechanism for vitamin C reformation?

Answer 6

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.

Question 7

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

Answer 7

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

Question 8

The RDA for vitamin C is___

Answer 8

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

Question 9

What is a sign of vitamin C toxicity?

Answer 9

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

Question 10

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

Answer 10

1) provitamines: vitamin A precursors such as carotenoids.

2) retinoids: retinol, retinoic acid.

Question 11

Retinol vs retinoic acid?

Answer 11

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.

Question 12

Purpose of retinol binding protein?

Answer 12

helps circulate vitamin A through the blood

Question 13

What is rhodopsin?

Answer 13

a complex formed by retinal and the opsin protein.

Question 14

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

Answer 14

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.

Question 15

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

Answer 15

retinoic acid.

Question 16

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

Answer 16

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.

Question 17

Two types of eye conditions caused by vitamin A deficiency

Answer 17

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

Question 18

Why does lack of vitamin A cause fetal development abnormalities?

Answer 18

because vitamin A plays a roll in cell differentiation.

Question 19

why does lack of vitamin A cause increased infection risk?

Answer 19

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

Question 20

what is hypercarotenemia

Answer 20

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

Question 21

If vitamin E fat soluble or water soluble

Answer 21

fat soluble

Question 22

What does vitamin E do?

Answer 22

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

Question 23

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

Answer 23

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

Question 24

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

Answer 24

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

Question 25

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

Answer 25

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.