Deck 10: Nutrients Involved in Body Defenses

Question 1

A high intake of vitamin E can

A) inhibit vitamin K metabolism.
B) result in lead poisoning.
C) inhibit copper absorption.
D) cause baldness.

Answer 1

The minerals like copper and zinc are known to interact at the intestinal mucosal level and thus affect the absorption of copper. Ascorbic acid is known to inhibit the absorption of copper. The excessive intake of iron or vitamin C is also known to inhibit the absorption of copper.
The intake of excess of lead especially from pain can lead to lead poisoning. The excess intake of vitamin A can also cause development of toxicity. The problem of baldness is common among men and is related to the male hormone dihydrotestosterone.
Hence the incorrect options are b, c and d.The intake of vitamin E above the recommended upper level would interfere with the role of vitamin K in the clotting mechanism. This can lead to the development of haemorrhage. Therefore it is advised to avoid the administration of vitamin E along with anticoagulant medications.
Hence the correct option is .

Question 2

Describe the process by which an antioxidant can prevent a free radical from damaging cells.

Answer 2

We eat variety of foods containing different kinds of nutrients. Some of the nutrients we eat, act as antioxidants and destroy free radicals in the body.Free radicals are reactive atoms with unpaired electrons in the outer shell. If these free radicals are allowed to roam freely in our system can damage cells. Some examples of antioxidants are vitamins, vitamin precursors and phytochemicals.
Free radicals steal electrons from adjacent atoms and destabilize them, while antioxidants donate electrons to atoms and stabilize them. After doing antioxidants can temporarily become unstable, but can be soon stabilized by reduction with the help of enzymatic reactions or non enzymatic reactions. Thus, antioxidants help in reducing the oxidative damage caused by reactive free radicals.
These mechanisms are functional in small amounts. But if this system gets overloaded with work due to oxidative stress, imbalances can lead to cellular dysfunction and conditions like cancer, cardiovascular problems, macular degeneration, cataract, Alzheimer's disease and other forms for age related tissue damage.
Hence, Antioxidants should be consumed in enough quantities in food so that we can prevent heath complication which may arise from the oxidative stress.

Question 3

Vitamin C is necessary for the production of

A) stomach acid.
B) collagen.
C) hormones.
D) clotting factors.

Answer 3

The endocrine system is responsible for the formation and storage of various hormones. The function similar to hormones is performed by vitamin D that regulates mineral metabolism for bones and other organs.
The acid in stomach is produced by parietal cells present in the gastric glands of the stomach. The main constituent of gastric acid is called as hydrochloric acid. Vitamin K is required to produce Prothrombin which is a protein and a clotting factor.
Hence the incorrect options are a, c and d.Vitamin C is necessary for the production of collagen. The organs of the body where the concentration of vitamin C is high are: connective tissue, bone, teeth, tendons and blood vessels. This vitamin is also important for the process of healing of wound and thus strengthens the tissues.
Hence the correct option is .

Question 4

Name three micronutrients that act as antioxidants by donating electrons or hydrogen atoms to unstable free radicals.

Question 5

Damage caused by free radicals is thought to contribute to

A) atherosclerosis.
B) Alzheimer's disease.
C) diabetes.
D) all of the above.

Question 6

Good food sources of vitamin E include
a. meats.
b. white bread.
c. nuts.
d. all of the above.

Question 7

Describe three functions of vitamin C.

Question 8

How would you determine which fruits and vegetables displayed in the produce section of your supermarket are likely to provide plenty of carotenoids?

Question 9

Supplementation with certain vitamins or minerals is most likely to be useful for

A) college students studying for finals.
B) older adults with low stomach acid production.
C) curing cancer.
D) preventing AIDS.

Question 10

What is the role of vitamin E in the prevention of cardiovascular disease? Should people at risk for cardiovascular disease take vitamin E supplements?

Question 11

Phytochemicals are

A) a new type of vitamin.
B) plant chemicals that protect health.
C) plant pigments that may be converted into vitamin A.
D) animal chemicals that protect health.

Question 12

Define the terms phytochemicals and functional foods. How do carotenoids fit into these definitions?

Question 13

Free radicals can

A) damage DNA.
B) disrupt cell membranes.
C) destroy pathogens.
D) All of the above.

Question 14

Selenium is an antioxidant micronutrient because it

A) donates electrons to free radicals.
B) accepts electrons from free radicals.
C) aids glutathione peroxidase activity.
D) enhances the absorption of vitamin E.

Question 15

What is the difference between reduction and oxidation? How do free radicals arise?

Question 16

What is the relationship between consumption of foods that are rich sources of antioxidants and a decreased risk for cancer?

Question 17

A deficiency of vitamin A can lead to the disease called

A) xerophthalmia.
B) Menkes syndrome.
C) scurvy.
D) anemia.

Question 18

Identify two beneficial roles of free radicals in the body.