Why is spinach not a great source of calcium?

• A. The oxalates in spinach limit the calcium absorption.
• B. It lacks the fats necessary for calcium absorption.
• C. The zinc in spinach interferes with calcium absorption.
• D. The calcium is not in the bioavailable heme form.

Answer: (A)

Verified step by step guidance

1. Understand the concept of calcium bioavailability: Calcium bioavailability refers to how well calcium can be absorbed and utilized by the body. Certain compounds in foods can enhance or inhibit calcium absorption.
2. Learn about oxalates: Oxalates are naturally occurring compounds found in some plants, including spinach. They can bind to calcium and form insoluble complexes, making the calcium less available for absorption in the digestive tract.
3. Examine the role of fats in calcium absorption: While fats can aid in the absorption of fat-soluble vitamins, they are not directly necessary for calcium absorption. Calcium absorption primarily depends on factors like vitamin D and the absence of inhibitors like oxalates.
4. Clarify the role of zinc: Zinc does not significantly interfere with calcium absorption in spinach. The primary issue with spinach is the presence of oxalates, not zinc.
5. Understand the form of calcium in spinach: Calcium does not need to be in a 'heme' form to be bioavailable. Heme refers to iron, not calcium. The bioavailability of calcium in spinach is limited due to oxalates, not its chemical form.