Foods that are rich in calcium include yogurt, mozzarella cheese, milk, kale, turnip greens and salmon with bones. Almonds, beans and blackstrap molasses also contain calcium. Some foods are enriched with calcium including some varieties of orange juice, ready-to-eat cereal, tofu and soy milk.
Calcium is essential for building and maintaining bones and teeth. This mineral also assists in blood clotting, blood vessel contraction and dilation, hormone function, muscle activity and nerve signaling. Approximately 99 percent of the calcium in the body is found in the bones and teeth, according to the National Institutes of Health. People who do not get enough calcium may develop osteoporosis, a disease in which the bones become thin and brittle. Calcium needs vitamin D to work properly, so this vitamin is often added to dairy products that contain calcium.
Calcium is also available as a dietary supplement and is included as an ingredient in many multivitamins. Calcium absorption in the body decreases when the intake rises above about 500 milligrams per dose, so individuals who need more than this amount should take multiple smaller doses throughout the day instead of taking a single large dose.
The recommended dietary allowance of calcium for adults between 19 and 50 is 1,000 milligrams per day, while teens between 14 and 18 years old need 1,300 milligrams a day.