Rochester, Minnesota - Getting the right amount of calcium every day is important for keeping your bones healthy throughout your life. But what is the right amount? And when should you consider taking a calcium supplement?

Calcium is an essential mineral that keeps your bones strong. But your body doesn't make it on its own.

"Calcium is exclusively in the diet," says Dr. Kurt Kennel, a Mayo Clinic endocrinologist. "There are some foods that are very rich in calcium."

He says milk and other dairy products are rich in calcium. So are other foods you might not think of, such as nuts, soy products and green, leafy vegetables, including spinach and kale. So how much calcium does the average adult need?

"A good number as a frame of reference would be 1,000 milligrams a day," says Dr. Kennel.

He says a balanced diet has that covered. A glass of milk or a 6-ounce yogurt alone is 300 milligrams. But, for the elderly, or people with osteoporosis or dietary issues, a daily calcium supplement might be necessary.

"People who are lactose-free and dairy-free, and otherwise have restrictions, they may find themselves only getting 400 or 500 milligrams of calcium per day," says Dr. Kennel. "And a supplement once a day would be very reasonable."