Natural Health Products

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General Information

The most common mineral in the human body is calcium. It is important for many of the body’s functions, including proper muscle function, nerve transmission, secretion of hormones, and development and maintenance of bones and teeth, and it helps prevent bone loss and osteoporosis. Your bones and teeth store more than 99% of the calcium in your body. Calcium is also found elsewhere, including in blood and muscle.

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Scientific Name(s)
How is this product usually used?

Calcium is normally taken by mouth. It is available in many forms, including tablets, capsules, chewable tablets, gummies, powders, and liquids. The daily Recommended Dietary Allowance (RDA) and the Tolerable Upper Intake Level (UL; the highest amount that can be taken daily without causing side effects in most people) for calcium vary with age. Below is a table showing the RDA and UL values based on age.

Age group Recommended Dietary Allowance (RDA) per day Tolerable Upper Intake Level (UL) per day
Infants 0 to 6 months 200 mg * 1,000 mg
Infants 7 to 12 months 260 mg * 1,500 mg
Children 1 to 3 years 700 mg 2,500 mg
Children 4 to 8 years 1,000 mg 2,500 mg
Children 9 to 18 years 1,300 mg 3,000 mg
Adults 19 to 50 years 1,000 mg 2,500 mg
Adults 51 to 70 years
1,000 mg**
1,200 mg
2,000 mg
2,000 mg
Adults over 70 years 1,200 mg 2,000 mg
Pregnant & breast-feeding
14 to 18 years:
19 to 50 years:
1,300 mg
1,000 mg
3,000 mg
2,500 mg

* Adequate Intake rather than Recommended Dietary Allowance
** Osteoporosis Canada recommends that men over 50 should consume 1,200 mg of calcium each day to reduce the risk of osteoporosis.

Calcium is found in combination with other substances called "compounds." Some examples of calcium compounds used as calcium supplements include calcium carbonate, calcium citrate, and calcium phosphate. Each type of calcium compound has a different amount of "elemental" calcium (i.e., the actual amount of calcium); therefore, brands of supplements that contain different calcium compounds may have different instructions for proper use. It is important to read labels carefully or to speak with a health care provider before using calcium supplements to make sure you are getting the right amount.

Your health care provider may have recommended using this product in other ways. Contact a health care provider if you have questions.

What is this product used for?

Calcium is important for maintaining overall good health. It helps build and maintain strong bones and teeth, especially in childhood, adolescence, and young adulthood. Taking calcium throughout life may also reduce the risk of developing osteoporosis (a disease that leads to fragile bones and a higher risk of fractures), especially when combined with the following:

  • adequate vitamin D intake
  • regular exercise
  • a healthy diet

Calcium may help prevent calcium deficiency when taken in the recommended daily amount.

People have also used calcium to help:

  • treat heartburn or dyspepsiadyspepsiaindigestion or upset stomach; discomfort due to indigestion (calcium carbonate is a common over-the-counter antacid)
  • prevent osteoporosis due to long-term corticosteroid use
  • treat kidney failure
  • treat hyperkalemia (an elevated level of potassium in the blood)
  • treat premenstrual syndrome (PMS)
  • lower cholesterol levels
  • treat or prevent high blood pressure

Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.

What else should I be aware of?

Calcium supplements appear to be safe for most people, including children, pregnant women, and women who are breast-feeding, when used in the daily recommended amounts.

Calcium supplements are effective for people with low calcium intakes, to help reduce the risk of developing osteoporosis, and as an antacid to treat heartburn or dyspepsiadyspepsiaindigestion or upset stomach.

Some research suggests that low dietary calcium can worsen the symptoms of premenstrual syndrome (PMS). Taking 1,000 mg to 1,200 mg per day may help with symptoms such as depressed mood, bloating (water retention), or pain.

Research suggests that taking calcium supplements in the recommended daily amount may slightly lower cholesterol when combined with a low-fat or low-calorie diet.

If you have high blood pressure you may also benefit from calcium. Several studies have shown that calcium supplements slightly lower blood pressure for people with or without hypertensionhypertensionhigh blood pressure.

Calcium supplements are not associated with significant side effects. Some people who take calcium may experience the following side effects:

  • belching
  • passing gas
  • constipation
  • diarrhea
  • stomach upset

Taking calcium at the recommended daily dose in combination with vitamin D can help your body absorb calcium better.

Calcium supplements may interact with other medications. If you are using calcium supplements, ask your pharmacist whether they should be taken a few hours before or after other medications.

There may be an interaction between calcium and the following medications:

  • bisphosphonates (e.g., alendronate, risedronate, etidronate)
  • calcipotriene
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine)
  • ceftriaxone
  • digoxin
  • diltiazem
  • iron
  • levothyroxine
  • lithium
  • magnesium
  • quinolone antibiotics (e.g., ciprofloxacin, levofloxacin)
  • sotalol
  • tetracycline antibiotics (e.g., doxycycline, minocycline)
  • thiazide diureticdiuretican agent that increases urine flows (e.g., hydrochlorothiazide, indapamide, etc.)
  • verapamil

Talk to your doctor before using calcium if you are taking any of these medications.

Your health condition may affect your body’s need and ability to use calcium. Talk to your health care provider before using calcium supplements if you have any of the following diseases or conditions:

  • achlorhydria (a condition where there is low or no production of stomach acid)
  • hyperparathyroidism (high levels of parathyroid hormone, which are involved in controlling calcium, vitamin D, and phosphorus levels in the body)
  • low or high phosphate blood levels
  • hypothyroidism (low thyroid hormone levels in the body)
  • reduced kidney function
  • sarcoidosis (an inflammatory disease that causes lumps of cells to form on various organs in the body, including the lungs, lymph nodes, and skin)

Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.



  1. Health Canada. Vitamin D and Calcium: Updated Dietary Reference Intakes. Available from: Accessed 18 May 2014.
  2. Natural Database. Natural Medicines Comprehensive Database. Calcium. Available from: ©2009 Accessed 18 May 2014.
  3. Health Canada. Drugs and Health Products. Calcium. Available from: Accessed 18 May2014.
  4. Osteoporosis Canada. Calcium: An Important Nutrient that Builds Stronger Bones. . Available from: Accessed 18 May 2014.
  5. Natural Standard. The Authority on Integrative Medicine. Natural Standard Monograph: Calcium. ©2013. Accessed 18 May 2014

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