A nurse is reinforcing teaching with a middle-aged client who is at high risk for osteoporosis and is taking oral calcium gluconate. Which of the following instructions should the nurse include in the teaching?

A. Whole grain cereals contain phytates, which can bind calcium and decrease its absorption; this is not recommended. B. Vitamin D enhances calcium absorption in the gut and is recommended for clients taking calcium supplements, making this correct. C. Calcium can be taken with or without food, but absorption may be better when taken with meals, not strictly on an empty stomach. D. Zinc-rich foods do not significantly enhance calcium absorption; focus should be on vitamin D and adequate dietary calcium.