Final answer:
Calcium supplementation can lead to constipation and should be suspected as the cause when a patient on mineral supplements reports such symptoms.
Step-by-step explanation:
Among the minerals listed, the nurse should identify calcium as the possible cause of constipation. Calcium supplementation can lead to constipation, which is a known side effect. It is essential for a variety of physiological processes, including bone mineralization and nerve function, but excessive consumption can affect the digestive system. Unlike the other minerals mentioned, such as phosphorus, potassium, and magnesium, which do not commonly cause constipation, calcium can reduce bowel motility, leading to this discomfort. It is significant that individuals on calcium supplements maintain adequate fluid and fiber intake to mitigate this side effect.