Question 1

Which of the following statements best explains why vitamins are considered essential nutrients?

Accepted Answer

They are organic compounds needed in small amounts for normal body functioning and must be obtained from the diet.

Question 2

A patient presents with night blindness and reports a diet low in animal products. Which vitamin deficiency is most likely responsible, and what is a key food source to recommend?

Accepted Answer

Vitamin A deficiency; recommend liver or fortified milk.

Question 3

Which of the following best describes the difference in absorption and storage between fat-soluble and water-soluble vitamins?

Accepted Answer

Fat-soluble vitamins are absorbed with dietary fat and stored in body tissues, while water-soluble vitamins are absorbed directly into the bloodstream and not stored extensively.

Question 4

A person taking high doses of vitamin D supplements develops hypercalcemia. Which physiological process explains this adverse effect?

Accepted Answer

Vitamin D increases intestinal absorption of calcium, leading to elevated blood calcium levels.

Question 5

Which vitamin is synthesized by intestinal bacteria and plays a crucial role in blood clotting?

Accepted Answer

Vitamin K

Question 6

A diet high in raw egg whites can lead to a deficiency in which vitamin, and what is the mechanism?

Accepted Answer

Biotin; avidin in raw egg whites binds biotin and prevents its absorption.

Question 7

Which of the following is a primary function of vitamin C in the body?

Accepted Answer

It is required for collagen synthesis and acts as an antioxidant.

Question 8

A patient with a history of alcoholism presents with confusion, ataxia, and memory loss. Which vitamin deficiency is most likely, and what is the syndrome called?

Accepted Answer

Thiamin (Vitamin B1) deficiency; Wernicke-Korsakoff syndrome.

Question 9

Which vitamin is most likely to reach toxic levels when consumed in excess from supplements, and why?

Accepted Answer

Vitamin A, because it is fat-soluble and stored in the liver.

Question 10

A pregnant woman is advised to take an extra 400 $\mu$g of folic acid daily. What is the primary reason for this recommendation?

Accepted Answer

To reduce the risk of neural tube defects in the developing fetus.

Question 11

Which of the following best describes the role of antioxidants such as vitamin E in the body?

Accepted Answer

They neutralize free radicals, preventing cellular damage.

Question 12

A patient presents with macrocytic anemia and neurological symptoms. Lab results show low vitamin B12 but normal folate. What is the most likely cause?

Accepted Answer

Vitamin B12 deficiency impairs folate utilization, leading to macrocytic anemia.

Question 13

Which of the following is a distinguishing feature of water-soluble vitamins compared to fat-soluble vitamins?

Accepted Answer

They are generally not stored in the body and excess is excreted in urine.

Question 14

A person following a strict vegan diet is at increased risk for which vitamin deficiency, and why?

Accepted Answer

Vitamin B12, because it is found only in animal-derived foods.

Question 15

Which of the following scenarios is most likely to result in vitamin toxicity?

Accepted Answer

Taking megadoses of fat-soluble vitamin supplements over time.

Question 16

A patient is prescribed high-dose niacin to manage cholesterol. Which adverse effect should be monitored?

Accepted Answer

Flushing and potential liver toxicity.

Question 17

Which vitamin is required for the synthesis of collagen and enhances iron absorption from plant foods?

Accepted Answer

Vitamin C

Question 18

A child presents with bowed legs and delayed growth. Which vitamin deficiency is most likely, and what is the condition called?

Accepted Answer

Vitamin D deficiency; rickets.

Question 19

Which of the following best explains why it is important to avoid overcooking vegetables when trying to preserve their vitamin content?

Accepted Answer

Many vitamins are destroyed by heat, air, and water, so prolonged cooking reduces their bioavailability.

Question 20

Which of the following is a provitamin, and how does it function in the body?

Accepted Answer

Beta-carotene; it is converted to vitamin A in the intestinal wall or liver.

Vitamins (nutrition)

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