Calcium is an important mineral for the human body. It helps build and protect your teeth and bones.Getting enough calcium over your lifetime can help prevent osteoporosis.
Most people get enough calcium in their normal diet. Calcium is found in dairy foods and leafy green vegetables. Older women and men may need extra calcium to prevent their bones from getting thin (osteoporosis).
Your health care provider will tell you if you need to take extra calcium.
Types of calcium supplements
The two main forms of calcium pills are:
Calcium carbonate: Over-the-counter antacid products, such as Tums and Rolaids contain calcium carbonate. These sources of calcium carbonate do not cost very much. Each pill or chew provides 200 - 400 mg of calcium.
Calcium citrate: This is a more expensive form of the mineral. It is absorbed well on an empty or full stomach. People with low levels of stomach acid (a condition that is more common in people over age 50) absorb calcium citrate better than calcium carbonate.
Another type, calcium phosphate is less common.
When choosing a calcium supplement:
Look the word "purified" or the United States Pharmacopeia (USP) symbol on the label.
Watch out for supplements made from unrefined oyster shell, bone meal, or dolomite that don't have the USP symbol. They may have high levels of lead or other toxic metals.
How to take extra calcium
Increase the dose of your calcium supplement slowly. Start with 500 mg a day for a week, and then add more over time.
Try to spread the extra calcium you take over the day. Do not take more than 500 mg at a time. Taking calcium throughout the day will:
Allow more calcium to be absorbed
cut down on side effects such as gas, bloating, and constipation
The total amount of calcium adults need every day from food or calcium supplements:
19 - 50 years: 1,000 mg/day
51 - 70 years: Men - 1,000 mg/day; Women - 1,200 mg/day
71 years and over: 1,200 mg/day
The body needs vitamin D is needed to help absorb calcium. Try to choose calcium supplements that also contain vitamin D.
Side effects and safety
Do not take more than the recommended amount of calcium without your doctor's OK.
Try the following steps if you have side effects from taking extra calcium:
Drink more fluids.
Eat high-fiber foods
Switch to another form of calcium if the diet changes don't help.
Always tell your health care provider and pharmacist if you are taking extra calcium. Calcium supplements may change the way your body absorbs some medicines. These include certain types of antibiotics and iron pills. Taking extra calcium over a long period of time raises the risk of kidney stones in some people.
Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride. National Academy Press, Washington, DC, 2010.
NIH Osteoporosis and Related Bone Diseases National Resource Center. Calcium and vitamin D: Important at every age. Reviewed January 2012 http://www.niams.nih.gov/Health_Info/Bone/Bone_Health/Nutrition/ (accessed February 3, 2013).
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.