What primarily determines the Dietary Reference Intake (DRI) for protein?

Correct Answer: D

Rationale: The Dietary Reference Intake (DRI) for protein is primarily determined by an individual's body weight. This is because the body's protein requirement is proportionate to its size, which is generally reflected in the body weight. Therefore, choice D is correct. Choices A, B, and C are incorrect: While factors such as fatty acid intake, gender, and height can influence an individual's overall nutritional needs, they do not directly determine the DRI for protein.

Correct Answer: A

Rationale: The correct answer is A: vitamin B12. Intrinsic factor is a glycoprotein produced by the stomach that is necessary for the absorption of vitamin B12 in the small intestine. Vitamin B12 binds to intrinsic factor in the stomach, forming a complex that is then absorbed in the ileum. This absorption process is crucial for preventing vitamin B12 deficiency. Choices B, C, and D are incorrect because they do not require intrinsic factor for absorption. Folate is absorbed in the small intestine through a different mechanism, niacin can be absorbed in the small intestine without the need for intrinsic factor, and vitamin B6 does not rely on intrinsic factor for absorption.

Correct Answer: D

Rationale: In pharmacology and nutrition, understanding the different vitamins is crucial. In this case, tocopherol is a form of Vitamin E. The correct answer is D because tocopherol is a group of compounds with vitamin E activity, known for its antioxidant properties. Vitamin E plays a vital role in protecting cells from damage and supporting immune function. Option A, Vitamin B1 (thiamine), is incorrect as tocopherol is not a form of B1. Option B, Vitamin B2 (riboflavin), and Option C, Vitamin B3 (niacin), are also incorrect as tocopherol is not associated with these vitamins. Educationally, this question emphasizes the importance of distinguishing between different vitamins and their functions. It highlights the role of Vitamin E in the body and its significance for overall health. Understanding these distinctions is essential for healthcare professionals when advising patients on nutrition and supplementation.

Correct Answer: C

Rationale: The correct answer is vitamin E. Vitamin E is the major antioxidant found in cell membranes, where it plays a crucial role in protecting them from oxidative damage. Although B12, beta-carotene, and vitamin A are important nutrients with specific functions in the body, they are not the primary antioxidants found in cell membranes. Vitamin E specifically localizes in cell membranes to neutralize free radicals and prevent lipid peroxidation, making it an essential antioxidant for cellular health.

Correct Answer: A

Rationale: Salmon is the correct answer as it is a rich source of omega-3 fatty acids, specifically EPA and DHA, which are known to be beneficial for heart health. Chicken, spinach, and eggs do not contain significant levels of omega-3 fatty acids compared to salmon. While eggs do contain some omega-3s, the amount is considerably lower than what is found in fatty fish like salmon.