Which provides the most absorbable iron?

Question

BlackTom AI · Accepted Answer

Heme iron (from animal flesh) is absorbed much more efficiently than nonheme iron (from plants), so the meat choice provides the most absorbable iron.

1) Relevant knowledge points and concepts
- Two forms of dietary iron: heme (in animal products) and nonheme (in plants and dairy).  
- Heme iron has higher bioavailability (commonly 15–35% absorption) and is less affected by dietary inhibitors. Nonheme iron has lower absorption (often 2–20%) and is inhibited by compounds such as oxalates, phytates, calcium, and some polyphenols.  
- Typical iron contents: 85 g (3 oz) cooked beef ≈ 2.0–3.0 mg iron (mostly heme); 1/2 cup cooked spinach ≈ 3–4 mg iron but largely nonheme and bound by oxalates; banana ≈ 0.3 mg iron; 30 g cheese ≈ 0.1–0.2 mg iron.

2) Step-by-step reasoning
- Identify iron form and amount in each option.  
- Estimate absorbed iron using typical absorption rates for heme vs nonheme.

3) Calculations (intermediate steps)
- 85 g steak: assume ~2.5 mg total iron (heme). Using a conservative heme absorption of 20%: 2.5 mg × 0.20 = 0.50 mg absorbed.  
- 1/2 cup cooked spinach: assume ~3.5 mg total iron (nonheme). Using a low nonheme absorption of 5% due to oxalates: 3.5 mg × 0.05 = 0.175 mg absorbed.  
- 1 banana: ≈ 0.3 mg iron; nonheme absorption ~5% → 0.3 × 0.05 = 0.015 mg absorbed.  
- 30 g cheese: ≈ 0.1–0.2 mg iron; absorption negligible → ≈0.005–0.01 mg absorbed.

4) Why the correct answer is correct
- Even if cooked spinach has similar or slightly higher total iron per serving, its nonheme iron is much less bioavailable due to inhibitors (oxalates), so the net absorbed iron from steak (heme iron) is greater. The steak therefore supplies the most absorbable iron per serving.

5) Why other options are incorrect
- Spinach (d): higher total iron but mostly nonheme and poorly absorbed.  
- Banana (c): very low total iron.  
- Cheese (b): minimal iron content and low absorption.

6) Conclusion
- Therefore the most absorbable iron is provided by 85 g steak (option a), matching the provided correct answer.

Which provides the most absorbable iron?单项选择题

类似问题

Which vitamin enhances the absorption of iron?

Iron absorption in humans is facilitated by the presence of:

Which of the following factors can enhance intestinal iron absorption?

Iron absorption is impaired by:

Which of the following increases the absorption of iron?

Comprehension-Level Multiple-Choice Items Which of the following impairs iron absorption?

Comprehension-Level Multiple-Choice Items A zinc toxicity reduces ____.

Which of the following does not inhibit the body’s absorption of iron?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单