Correct Answer: A

Rationale: Chromium is essential for proper glucose metabolism. A deficiency in chromium can result in insulin resistance, which shares similarities with diabetes. Iron, molybdenum, and selenium deficiencies do not directly lead to a diabetes-like condition. Iron deficiency causes anemia, molybdenum deficiency is rare and can lead to specific metabolic issues, and selenium deficiency may result in thyroid problems but not a diabetes-like condition.

Correct Answer: A

Rationale: Patients with kidney stones should increase their intake of fluids. Increasing fluid intake helps to dilute the urine and reduce the risk of kidney stones forming by flushing out minerals that can crystallize. This promotes the passage of small stones and helps prevent the formation of new ones. Vitamin C and protein intake should be moderated as excessive consumption may lead to the formation of certain types of kidney stones. Oxalates should be limited in the diet as they can contribute to the formation of calcium oxalate stones, a common type of kidney stone.

Correct Answer: B

Rationale: The correct answer is B: 'be obtained by the diet.' Essential nutrients are those that the body cannot synthesize in sufficient quantities and must therefore be obtained through the diet. Choice A is incorrect because not all essential nutrients need to be consumed daily; the frequency of consumption varies. Choice C is incorrect because not all essential nutrients are water-soluble; they can be water-soluble or fat-soluble. Choice D is incorrect because essential nutrients do not need to be consumed at every meal, but rather need to be included in the overall diet regularly.

Correct Answer: A

Rationale: The correct answer is A: 'they must be supplied by the diet.' Essential fatty acids, like omega-3 and omega-6, cannot be produced by the body and must be obtained through the diet. They are polyunsaturated fatty acids, playing vital roles in inflammation and cell membrane structure. Choice B is incorrect because essential fatty acids cannot be produced by dehydrogenation, a process of removing hydrogen. Choice C is incorrect as not all essential fatty acids are anti-inflammatory; some have pro-inflammatory roles. Choice D is incorrect because not all essential fatty acids are polyunsaturated; omega-9, for example, is a monounsaturated essential fatty acid.

Correct Answer: D

Rationale: Phytochemicals are not considered a class of nutrients. While proteins, fats, and carbohydrates are essential macronutrients providing energy and structural support, phytochemicals are non-nutrient compounds found in plants that offer various health benefits but are not essential for sustaining life like the other three choices. Therefore, the correct answer is D.