Each statement regarding the correlation between vitamin D and sun exposure is accurate, except one. Which is the exception?

Correct Answer: C

Rationale: While UV radiation can penetrate uncovered skin and convert a precursor of vitamin D to vitamin D3, sunscreen does block the formation of vitamin D3. Sunscreen is recommended by dermatologists to prevent sunburn and reduce the risk of skin cancer. The other choices are correct: the body can produce sufficient vitamin D from sunlight, UV radiation can convert a precursor of vitamin D to vitamin D3, and skin generally produces less vitamin D as a person ages.

Correct Answer: C

Rationale: Scurvy is caused by a deficiency of vitamin C, not vitamin E. The symptoms of scurvy include spontaneous gingival hemorrhaging, perifollicular petechiae, follicular hyperkeratosis, diarrhea, fatigue, depression, and cessation of bone growth. Vitamin A (Choice A) is important for vision and immune function, Vitamin D (Choice B) is essential for bone health, and Vitamin K (Choice D) is necessary for blood clotting. However, none of these vitamins are associated with scurvy.

Correct Answer: B

Rationale: A deficiency in iron can lead to various symptoms, such as microcytic anemia, fatigue, faulty digestion, blue sclerae, pale conjunctivae, and tachycardia. Iron-deficiency anemia may be caused by inadequate dietary intake; accelerated demand or losses; and inadequate absorption secondary to diarrhea, decreased acid secretions, or antacid therapy. Iron deficiency is frequently the result of postnatal feeding practices and has a serious impact on growth and mental and psychomotor development in infants and children. Choices A, C, and D are incorrect as zinc deficiency typically presents with symptoms like impaired wound healing, taste abnormalities, and hair loss; sodium deficiency can lead to symptoms such as muscle cramps, dizziness, and confusion; and potassium deficiency may cause muscle weakness, fatigue, and abnormal heart rhythms.

Correct Answer: A

Rationale: The correct answer is A, Beans. Beans are known to be a good source of protein compared to the other options provided. While red peppers, asparagus, and celery are nutritious vegetables, they do not contain as much protein as beans do. Red peppers are high in vitamin C, asparagus is rich in vitamins and minerals, and celery is low in calories and a good source of fiber, but they are not significant sources of protein.

Correct Answer: B

Rationale: The correct answer is B. Magnesium plays an important role in maintaining calcium homeostasis and preventing skeletal abnormalities. It is involved in more than 300 enzymatic reactions, including energy metabolism, insulin activity, and glucose use. Magnesium is vital to the structural integrity of heart muscle and other muscles and nerves. While magnesium does play a role in blood clotting, nerve impulses, muscle contraction, relaxation, ATP energy release, and metabolism of fats, carbohydrates, proteins, the primary physiologic role of magnesium in the body is related to calcium homeostasis and maintaining the structural integrity of the heart muscle. Choice A is incorrect because it includes functions of magnesium, but they are not its primary physiologic role. Choice C is incorrect as magnesium has several known metabolic functions. Choice D is incorrect because although magnesium is involved in ATP energy release and metabolism, its primary role is related to calcium homeostasis and structural integrity of muscle.

Correct Answer: B

Rationale: The Estimated Average Requirement (EAR) is specifically designed to assess nutrient adequacy or plan intakes for population groups, not for individuals. The Old and New Recommended Dietary Allowances (RDA) are meant for individuals, not groups, as they provide guidelines for specific nutrient intake levels for healthy individuals. The Tolerable Upper Intake Level (UL) is used to set the highest level of nutrient intake that is likely to pose no risk of adverse health effects for most individuals in a group, which is different from assessing nutrient adequacy for groups.

Correct Answer: D

Rationale: Iron, fiber, and B vitamins are most likely to become insufficient when carbohydrates are eliminated from the diet to lose weight. Carbohydrates are a primary source of B vitamins and fiber in the diet. Iron can also be obtained from plant-based sources like legumes and whole grains, which are often eliminated when carbohydrates are restricted. Choices A, B, and C are incorrect because protein, vitamin K, vitamin A, and vitamin C are not primarily sourced from carbohydrates and are less likely to become insufficient solely due to carbohydrate elimination.

Correct Answer: C

Rationale: While UV radiation can penetrate uncovered skin and convert a precursor of vitamin D to vitamin D3, sunscreen does block the formation of vitamin D3. Sunscreen is recommended by dermatologists to prevent sunburn and reduce the risk of skin cancer. The other choices are correct: the body can produce sufficient vitamin D from sunlight, UV radiation can convert a precursor of vitamin D to vitamin D3, and skin generally produces less vitamin D as a person ages.

Correct Answer: C

Rationale: The first statement is true; the second is false. Complex carbohydrates are also called polysaccharides and contain more than 10 monosaccharides. Choice A is incorrect because the second statement is false. Choice B is incorrect because the first statement is true. Choice D is incorrect because the second statement is false.