Calcium is the most abundant mineral in the human body. Most of the calcium in your body, about 99 percent, is found in your bones and teeth, while the remaining calcium is spread among your blood, nerves, body tissues and other body fluids, according to MedlinePlus. Because calcium is your body’s most abundant mineral, it’s also one of the most important.
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What It Does
Calcium combines with phosphorus to form hydroxyapatite, the main structural component in your bones and teeth. Without adequate amounts of calcium in your diet, your bones become weak and your risk of developing osteoporosis increases. The calcium outside of your bones plays a role in the contraction and relaxation of muscles, transmission of nerve impulses and blood coagulation. A number of chemical reactions also rely on the presence of calcium.
What You Need
The amount of calcium you need each day depends on your age and sex. Adults between the ages of 19 and 50 need 1,000 milligrams per day. After 50, a woman’s needs increase to 1,200 milligrams per day, while a man’s needs remain at 1,000 milligrams daily. Above the age of 70, both men and women should consume 1,200 milligrams of calcium each day. It doesn't matter how much calcium you get, though, if you don't consume enough vitamin D. Vitamin D allows you to absorb calcium into your bloodstream, so that your body can effectively use the mineral. Adults between 19 and 70 need 600 international units of vitamin D daily, while adults over 70 need 800 international units.
Where You Get It
Milk, yogurt and cheese are the major sources of calcium in the United States, according to the Office of Dietary Supplements. An 8-ounce cup of low-fat yogurt contains 415 milligrams of calcium, while a cup of skim milk offers 306 milligrams. Dark greens such as kale, broccoli, Chinese cabbage and collard greens, also offer significant amounts of calcium. A cup of collard greens contains 357 milligrams of calcium. Canned salmon and sardines, which contain fine, edible bones, also contain calcium. Many foods and drinks, such as breakfast cereals, fruit juices and soy beverages, are fortified with calcium to help you meet your needs. Vitamin D is a little harder to get, because there are very few natural sources. Salmon, tuna and mackerel are the best dietary sources of vitamin D, although beef liver, cheese and egg yolks provide the vitamin as well. Vitamin D is added to fortified milk and some orange juices, yogurt and soy products. You can also get vitamin D from exposure to the sun..
A Word on Supplements
Although it’s best to get your calcium through a well-balanced diet, sometimes supplementation is necessary to meet your needs. Calcium supplements are available in many forms, including calcium citrate and calcium carbonate, according to the University of Maryland Medical Center. Calcium citrate is more easily absorbed by the body, but often contains less elemental calcium -- the kind your body actually uses -- than calcium carbonate. Take calcium supplements in divided doses -- no more than 500 milligrams at a time -- throughout the day. Total calcium consumption from food and supplements should not exceed 2,500 milligrams per day. Talk to your doctor before beginning a new supplement regimen.