Question 1

Which of the following statements best explains why fat-soluble vitamins are more likely to cause toxicity than water-soluble vitamins?

Accepted Answer

Fat-soluble vitamins are stored in body fat and not easily excreted.

Question 2

A patient presents with night blindness and dry, keratinized epithelial tissue. Which nutrient deficiency is most likely responsible for these symptoms?

Accepted Answer

Vitamin A

Question 3

Which of the following best describes the role of vitamin D in calcium homeostasis?

Accepted Answer

Vitamin D increases intestinal absorption of calcium by turning on genes for calcium transport.

Question 4

A newborn is diagnosed with hemolytic anemia. Which vitamin deficiency is most likely the cause, and why?

Accepted Answer

Vitamin E, because it protects red blood cell membranes from oxidative damage.

Question 5

Which of the following foods is the best source of preformed vitamin A?

Accepted Answer

Egg yolks

Question 6

A patient taking warfarin (an anticoagulant) is advised to maintain a consistent intake of which vitamin to avoid interfering with their medication?

Accepted Answer

Vitamin K

Question 7

Which of the following statements about carotenoids is TRUE?

Accepted Answer

Some carotenoids, such as beta-carotene, are vitamin A precursors and may function as antioxidants.

Question 8

A 65-year-old woman with limited sun exposure is at increased risk for which deficiency, and what condition might result?

Accepted Answer

Vitamin D deficiency; resulting in osteomalacia

Question 9

Which fat-soluble vitamin is most directly involved in the synthesis of proteins required for normal blood clotting?

Accepted Answer

Vitamin K

Question 10

A person consumes large amounts of carrot juice daily and develops yellow-orange skin but no other symptoms. What is the most likely explanation?

Accepted Answer

Hypercarotenemia from excess beta-carotene intake

Question 11

Which of the following best explains why vitamin E supplementation can interfere with blood clotting?

Accepted Answer

Vitamin E inhibits an early step in blood clot formation.

Question 12

Which fat-soluble vitamin is synthesized in the skin upon exposure to ultraviolet light and must be activated in the liver and kidneys?

Accepted Answer

Vitamin D

Question 13

A patient presents with bruising and uncontrolled bleeding. Which vitamin deficiency is most likely, and what is the physiological explanation?

Accepted Answer

Vitamin K deficiency; due to impaired synthesis of clotting factors

Question 14

Which of the following is a shared function of both vitamins A and D?

Accepted Answer

Both regulate gene expression and influence cell differentiation.

Question 15

A patient with a history of fat malabsorption is at risk for deficiencies in which group of vitamins?

Accepted Answer

Vitamins A, D, E, and K

Question 16

Which of the following scenarios best illustrates the consequences of vitamin D toxicity?

Accepted Answer

An adult experiences high blood calcium, kidney stones, and cardiovascular damage.

Question 17

Which equation best represents the conversion of a vitamin A precursor to its active form in the body?

Accepted Answer

$$ 	ext{Beta-carotene} \xrightarrow{	ext{Enzymatic cleavage}} 	ext{Retinal} $$

Question 18

Which of the following is a function of vitamin K2 (menaquinone) that is NOT shared by vitamin E?

Accepted Answer

Inhibition of blood vessel calcification

Question 19

A patient with a diet low in leafy-green vegetables and vegetable oils is most at risk for which deficiency symptom?

Accepted Answer

Abnormal blood clotting

Question 20

Which of the following best describes the relationship between parathyroid hormone (PTH) and vitamin D?

Accepted Answer

Low blood calcium stimulates PTH release, which activates vitamin D to increase calcium absorption.

Fat-Soluble Vitamins: Structure, Function, Deficiency, and Dietary Sources

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