Which combination of substances is known to prevent absorption of zinc and copper?

• A. Sulfate, iron, nitrates
• B. Sulfate, zinc, nitrates
• C. Sulfate, iron, phosphates
• D. Nitrates, copper, zinc

Answer: (A)

Absorption of trace minerals in the gut can be reduced when other substances bind or compete with them. Iron is known to compete with zinc (and copper) for uptake in the intestinal lining, so high iron levels can directly lower zinc and copper absorption. Sulfate and nitrate can further decrease mineral bioavailability by forming poorly soluble salts or complexes with zinc and copper in the gut, reducing their solubility and uptake. When combined, these three elements create multiple barriers to absorption for both minerals, making this mix the most effective at preventing zinc and copper absorption. The other options rely on fewer or less impactful interactions, so they don’t inhibit both minerals as consistently.