Health Topic

Calcium

Your body needs calcium for many reasons. Learn what foods are high in calcium and how much calcium you need in a healthy diet.

Reviewed Reviewed by a registered pharmacistGeneral information

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Calcium

Calcium is a mineral, a nutrient that you need (in small amounts) to keep your body healthy. You have more calcium in your body than any other mineral.

Calcium has many important jobs:

  • To build and maintain strong bones. Your body stores almost all of its calcium in your bones and teeth to keep them strong.
  • To help your muscles move.
  • To help your nerves to carry messages between your brain and the rest of your body.
  • To help your blood vessels move blood throughout your body.
  • To help release hormones that affect many functions in your body.

Not getting enough calcium can cause several conditions, including:

  • Osteoporosis, a disease which can make your bones weaker and more likely to break.
  • Rickets, a disease in children that causes soft, weak bones.
  • Osteomalacia, a condition which causes soft bones in children and adults.

You can get calcium from foods and supplements. You may be able to get enough calcium by eating a variety of foods, including:

  • Dairy products such as milk, cheese, and yogurt. These are the main food sources of calcium for most people in the United States.
  • Leafy, green vegetables such as kale, broccoli, and Chinese cabbage (bok choi).
  • Fish with soft bones that you can eat, such as canned sardines and salmon.
  • Calcium-enriched foods such as breakfast cereals, fruit juices, soy and rice drinks, and tofu. The product labels for these foods will show how much calcium they have.

Calcium is available in supplements. It is also included in many multivitamins. The two main forms of calcium supplements are calcium carbonate and calcium citrate:

  • Calcium carbonate is absorbed best when taken with food. Some over-the-counter antacids, such as Tums and Rolaids, also contain calcium carbonate.
  • Calcium citrate is absorbed well on an empty stomach or a full stomach. People with low levels of stomach acid absorb calcium citrate more easily than calcium carbonate.

Calcium is absorbed best when you take 500 mg or less at one time. If you are taking more than that amount each day, take a smaller dose twice a day rather than taking it all at once.

Calcium supplements might cause gas, bloating, and constipation in some people. If you have any of these symptoms, you could try:

  • Spreading out the calcium dose throughout the day
  • Taking it with meals
  • Switching the form of calcium you take

The amount of calcium you need each day depends on your age and other factors. The recommended amounts, in milligrams (mg), are:

  • Birth to 6 months: 200 mg
  • Infants 7-12 months: 260 mg
  • Children 1-3 years: 700 mg
  • Children 4-8 years: 1,000 mg
  • Children 9-13 years: 1,300 mg
  • Teens 14-18 years: 1,300 mg
  • Adults 19-50 years: 1,000 mg
  • Adult men 51-70 years: 1,000 mg
  • Adult women 51-70 years: 1,200 mg
  • Adults 71 years and older: 1,200 mg
  • Pregnant and breastfeeding teens: 1,300 mg
  • Pregnant and breastfeeding adults: 1,000 mg

Certain people may have trouble getting enough calcium, including:

  • Children and teens age 4 to 18 years
  • People who are Black or Asian
  • Adults age 50 years and older living in poverty
  • Postmenopausal women; your body absorbs and retains less calcium after menopause
  • People who don't drink milk or eat other dairy products

Check with your health care provider to see if you need to take calcium supplements, and if so, how much you should take. Your provider may want to first do a calcium blood test to see if you are getting enough of it.

It sits within Bones, Joints and Muscles and Food and Nutrition.

The lead U.S. institute for this subject is the NIH Office of Dietary Supplements.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Calcium

1,971 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

Start Here

Diagnosis and Tests

Related Issues

Genetics

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Calcium, Dietary. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Calcium, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.