Calcium is the most plentiful mineral found in the human body. The teeth and bones contain the most calcium. Nerve cells, body tissues, blood, and other body fluids contain the rest of the calcium.
Calcium is one of the most important minerals for the the human body. Calcium helps form and maintain healthy teeth and bones. Proper levels of calcium over a lifetime can help prevent osteoporosis.
Calcium helps your body with:
- Building strong bones and teeth
- Clotting blood
- Sending and receiving nerve signals
- Squeezing and relaxing muscles
- Releasing hormones and other chemicals
- Keeping a normal heartbeat
CALCIUM AND DAIRY PRODUCTS
Many foods contain calcium, but dairy products are the best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium that your body can absorb easily.
Whole milk (4% fat) is recommended for children ages 1 to 2. Adults and children over the age of 2 should drink low-fat (2% or 1%) or skim milk and other dairy products. Removing the fat will not lower the amount of calcium in a dairy product.
- Yogurt, most cheeses, and buttermilk are excellent sources of calcium and come in low-fat or fat-free versions.
- Milk is also a good source of phosphorus and magnesium, which help the body absorb and use calcium.
- Vitamin D is needed to help the body use calcium. Milk is fortified with vitamin D for this reason.
OTHER SOURCES OF CALCIUM
Green leafy vegetables such as broccoli, collards, kale, mustard greens, turnip greens, and bok choy or Chinese cabbage are good sources of calcium.
Other sources of calcium that can help meet your body's calcium needs:
- Salmon and sardines canned with their soft bones
- Almonds, Brazil nuts, sunflower seeds, tahini, and dried beans
- Blackstrap molasses
Calcium is added to several food products, such as orange juice, soy milk, tofu, ready-to-eat cereals, and breads. These are a very good source of calcium for persons who do not eat a lot of dairy products or who are on a vegan diet.
Ways to make sure you receive or absorb the calcium in your diet:
- Cook foods in a small amount of water for the shortest possible time to keep more calcium in the foods you eat.
- Be careful about what you eat with calcium-rich foods. Certain fibers, such as wheat bran and foods with oxalic acid (spinach and rhubarb) can bind with calcium and prevent it from being absorbed.
Calcium is also found in many multivitamin-mineral supplements. The amount varies depending on the. supplement. Dietary supplements may contain only calcium or calcium with other nutrients such as vitamin D. Check the label on the Supplement Facts panel to determine the amount of calcium. Calcium absorption is best when taken in amounts of no more than 500 mg at a time.
Two commonly available forms of calcium dietary supplements include citrate and carbonate.
- Calcium citrate is the more expensive form of the supplement. It is taken up well by the body on a full or empty stomach.
- Calcium carbonate is less expensive. It is absorbed better by the body if taken with food. Calcium carbonate is found in over-the-counter antacid products such as Rolaids or Tums. Each chew or pill usually provides 200-400 mg of calcium. Check the label for the exact amount.
Other types of calcium in supplements and foods include lactate, gluconate, and phosphate.
Increased calcium for a limited period of time does not normally cause side effects. However, receiving higher amounts of calcium over a long period of time raises the risk of kidney stones in some people.
Those who do not receive enough calcium over a long period of time can develop osteoporosis (thinning of bone tissue and loss of bone density over time). Other disorders are also possible.
Persons with lactose intolerance have trouble digesting lactose, the sugar in milk. Over-the-counter products are available that make it easier to digest lactose. You can also buy lactose-free milk at most grocery stores.
Tell your health care provider about any dietary supplements and medicines you take. Your provider can tell you if those dietary supplements might interact or interfere with your prescription or over-the-counter medicines. In addition, some medicines might interfere with how your body absorbs calcium.
The preferred source of calcium is calcium-rich foods such as dairy products. Some people will need to take calcium supplements.
The Recommended Dietary Allowance (RDA) for vitamins and minerals reflects how much of each vitamin or mineral most people should get each day. The RDA for vitamins and minerals may be used to help create the goal for each person.
How much calcium you need depends on your age and gender. Other factors, such as pregnancy and illnesses, are also important.
Infants (Adequate Intake)
- 0 - 6 months: 200 milligrams per day (mg/day)
- 7 - 12 months: 260 mg/day
Children and Adolescents
- 1 - 3 years: 700 mg/day
- 4 - 8 years: 1,000 mg/day
- 9 - 18 years: 1,300 mg/day
- 19 - 50 years: 1,000 mg/day
- 50 - 70 years: Men - 1,000 mg/day; Women - 1,200 mg/day
- Over 71 years - 1,200 mg/day
Pregnancy and Breast-feeding
- 14 - 18 years: 1,300 mg/day
- 19 - 50 years: 1,000 mg/day
Up to 2,500 - 3,000 mg a day of calcium from dietary sources and supplements appears to be safe for children and adolescents, and 2,000 - 2,500 mg a day appears to be safe for adults.
The following list can help you determine how much calcium you are getting from food:
- 8-ounce glass of milk = 300 mg of calcium
- 2 ounces of Swiss cheese = 530 mg of calcium
- 6 ounces of yogurt = 300 mg of calcium
- 2 ounces of sardines with bones = 240 mg of calcium
- 6 ounces of cooked turnip greens = 220 mg of calcium
- 3 ounces of almonds = 210 mg of calcium
Vitamin D is needed to help the body absorb calcium. When choosing calcium supplements, look for ones that also contain vitamin D.
Diet - calcium
Escott-Stump S, ed. Nutrition and Diagnosis Related Care. 6th ed. Philadelphia, Pa: Lippincott Williams and Wilkins; 2008.
Sarubin Fragaakis A, Thomson C. The Health Professional's Guide to Popular Dietary Supplements. 3rd ed. Chicago, Il:American Dietetic Association;2007.
Institute of Medicine. Food and Nutrition board. Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride. National Academy Press, Washington, DC, 2010.
National Institutes of Health, Office of Dietary Supplements. Dietary Supplement Fact Sheet: Calcium. Accessed February 12, 2013.
Update Date 2/18/2013
Updated by: Alison Evert, MS, RD, CDE, Nutritionist, University of Washington Medical Center Diabetes Care Center, Seattle, Washington. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.