A patient reports consuming 400 mg elemental calcium daily from spinach-based smoothies and no dairy. Lab shows marginal calcium status. Analyze why a large measured calcium content in spinach does not translate to adequate absorbed calcium and recommend two dietary modifications to improve absorbed calcium.

• A. Spinach has high oxalate content that binds calcium, reducing absorption; recommendations: replace some smoothies with low-oxalate greens (kale/cabbage) and ensure vitamin D adequacy via fortified foods or supplementation to enhance intestinal absorption
• B. Spinach contains phytates that increase fractional calcium absorption; recommendations: add phytate-rich legumes and avoid vitamin D to prevent overabsorption
• C. Spinach calcium is destroyed by blending; recommendations: stop blending and instead roast spinach to recover calcium, and avoid all dairy products
• D. Spinach leads to excess urinary calcium loss which is unique to leafy greens; recommendations: reduce fluid intake and increase dietary sodium to reduce oxalate binding

Answer: (A)