Which of the following has NOT been shown to limit copper absorption?

• A. Zinc.
• B. Vitamin D.
• C. Iron.
• D. Vitamin C.

Answer: (B)

Verified step by step guidance

1. Understand the context: Copper absorption can be influenced by various dietary factors. Some nutrients can enhance or inhibit its absorption in the body. The question asks which of the listed options does NOT limit copper absorption.
2. Review the role of each nutrient: Zinc, iron, and vitamin C are known to interact with copper absorption. For example, high levels of zinc and iron can compete with copper for absorption in the gastrointestinal tract.
3. Consider the role of Vitamin D: Vitamin D is primarily involved in calcium and phosphorus metabolism and does not have a known direct effect on copper absorption.
4. Eliminate options: Based on the known interactions, zinc, iron, and vitamin C can influence copper absorption, while vitamin D does not.
5. Conclude the reasoning: The correct answer is Vitamin D because it has NOT been shown to limit copper absorption, unlike the other options.