Dietary Reference Intake for Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride, National Academy of Sciences, National Academy Press, Washington, D.C., 1997. Some lactose-reduced milk has extra calcium added. Low-lactose cheeses and yogurt are also good sources of calcium. Your body can't absorb larger amounts at one time. Take with meals to help the calcium tablets dissolve and improve absorption.
Food helps stimulate production of the stomach acid needed to dissolve calcium supplements.
This is especially important for older adults. Add vitamin D unless you're already taking a multivitamin.