Health Benefits of Calcium

Pros and Cons of the Bone Health Supplement

Calcium is an essential mineral best known for strengthening the bones and teeth. It also plays a role in muscle contraction, blood clotting, the release of hormones, the transmission of nerve signals, the regulation of heartbeat, and the normal functioning of blood vessels.

Calcium is considered an essential nutrient because we can only get it from the foods we eat or supplements we take; the body cannot produce it on its own. If the body does not get enough calcium from dietary sources, it will obtain it from bone where over 99 percent of calcium is stored. If this happens, the bones can weaken and become vulnerable to breakage.

While milk, yogurt, cheese, and other dairy products are the principal sources of dietary calcium, you can also get it from certain vegetables, fruits, legumes, meat, grains, and eggs. There are also calcium-fortified foods (such as orange juice and soy milk) and dietary supplements that can help prevent calcium deficiency and bone loss as you age.

Health benefits of calcium
Illustration by Brianna Gilmartin, Verywell.

Health Benefits

Calcium supplements are typically taken to prevent osteoporosis, a condition that affects 55 percent of Americans over 50, most especially postmenopausal women.

Calcium can aid in the treatment of other health conditions by correcting imbalances in hormones or other essential minerals. This includes excessive concentrations of potassium in the blood (hyperkalemia), excessive phosphate (hyperphosphatemia) caused by kidney failure, or an overactive parathyroid gland (hyperparathyroidism) caused by kidney failure or parathyroid disease.

Calcium supplements may also help relieve bloating, pain, and mood swings associated with premenstrual syndrome (PMS).

According to a 2005 study in the Archives of Internal Medicine, a daily calcium intake of 1,283 milligrams per day resulted in a 30 percent decrease in PMS symptoms compared to a daily intake of 529 milligrams.


Osteoporosis, which literally means porous (-porosis) bone (osteo-), is a disease in which the density and quality of bone are reduced.

Most bone growth occurs during the teen years. After that, the bone density in women remains more or less the same until around the age of 40. After 40, bone loss typically occurs at rates of 0.5 percent to 1 percent per year. In men, the same can occur but usually around the age of 60.

According to a 2011 study published in the Journal of the American Dietetic Association, only 15 percent of men and 8 percent of women over 70 met the dietary intake needs of calcium or vitamin D (which aids in the absorption of calcium).


Although calcium can reduce the risk of osteoporosis, there remains controversy as to whether calcium supplements can actually prevent bone fractures. The evidence today remain mixed.

In 2018, the U.S. Preventive Services Task Force (USPSTF) stated there was "insufficient evidence" that calcium supplements reduce the risk of fractures in men and postmenopausal women or that doses over 1,000 milligrams could do the same for postmenopausal women.

To add further confusion, the agency asserted there was insufficient evidence that calcium supplements under 1,000 milligrams offered any protection against fractures in postmenopausal women.

With that being said, older adults in nursing homes or those with a history of fractures or at high risk of falls would likely benefit from calcium supplements. The same may apply to vegans or lactose intolerant individuals who don't get enough calcium from food.

For older adults who are mobile and otherwise healthy, there is nothing in the USPSTF recommendation to suggest you need to avoid calcium supplements. You would need, however, to avoid overdosing to prevent possible long-term harms to your health.

Possible Side Effects

Calcium supplements are generally safe and well-tolerated if taken at the prescribed dose. Some people may experience mild side effects, including gas, bloating, belching, and constipation.

When overused, calcium supplements may increase the risk of kidney stones, most often in people with a prior history of kidney stones. Calcium supplements should be used with extreme caution in people with kidney disease as it could lead to an excessive buildup of calcium in the bloodstream (hypercalcemia) and kidney stones.

There is also evidence, albeit controversial, that the long-term overuse of calcium may increase the risk of a heart attack. It is thought that excess calcium could make its way to fatty deposits in the arteries and accelerate the development of atherosclerosis (hardening of the arteries). Although there is little statistical evidence to support these concerns, it nevertheless warrants consideration if you are at risk of heart disease.

Drug Interactions

Calcium supplements may interact with certain medications. Calcium can attach to certain antibiotics and decrease their absorption. They can also reduce the effectiveness of thyroid hormone replacement drugs like Synthroid (levothyroxine) and angina medications like Cardizem (diltiazem).

In most cases, separating the doses by two to four hours can help minimize these interactions. Speak with your doctor to get the correct dosing instructions.

On the flip side, calcium may increase the concentration of Lanoxin (digoxin) used to strengthen your heartbeat. Taking them together can lead to abnormal heart rhythms (arrhythmia).

Taking calcium with thiazide diuretics ("water pills") can lead to the excessive buildup of calcium in the blood, as can the psoriasis drug Dovonex (calcipotriene).

Dosage and Preparation

Calcium supplements are typically sold in capsule, tablet, and soft gel cap forms at grocery stores, drugs stores, health food stores, and nutritional supplement stores.

The Food and Nutrition Board (FNB) at the Institute of Medicine has established the following recommended daily allowances (RDA) for calcium based on a person's age and sex:

  • Children 0 to 6 months: 200 milligrams per day
  • Children 7 to 12 months: 260 milligrams per day
  • Children 1 to 3 years: 700 milligrams per day
  • Children 4 to 8 years; 1,000 milligrams per day
  • Children 9 to 13 years: 1,300 milligrams per day
  • Teenagers 14 to 18 years: 1,300 milligrams per day
  • Adults 19 to 50 years: 1,000 milligrams per day
  • Men 51 to 70 years: 1,000 milligrams per day
  • Women 51 to 70 years: 1,200 milligrams per day
  • Adults 71 and over: 1,000 milligrams per day

Higher dose may be advised for vegan or lactose intolerant adults. Dosages of as high as 2,000 milligrams per day may be recommended to pregnant women with low calcium under the presumption that it may reduce the risk of pre-eclampsia.

Generally, a calcium supplement dose over 2,000 milligrams per day should be considered excessive in adults unless under the supervision of a doctor.

What to Look For

There are different types of calcium used in supplements, including calcium carbonate, calcium phosphate, and calcium citrate. Each contains a different amount of elemental calcium (the actual amount of calcium in the product). It is important to read the label carefully to determine how much elemental calcium is in the supplement so that you can dose correctly.

Each type of calcium is equally beneficial. Calcium carbonate and calcium phosphate are absorbed best when taken with food. Calcium citrate can be taken anytime.

Because dietary supplements are not strictly regulated in the United States, opt for brands that been submitted for voluntary inspection by the U.S. Pharmacopeia (USP), ConsumerLab, or other independent certifying bodies.

Other Questions

Which foods are highest in calcium?

Milk and other dairy products are the primary sources of calcium in the American diet, but there are other food sources you can turn to, especially if you are vegan or lactose intolerant. Among the foods highest in calcium are:

  • Yogurt: 415 milligrams per 8-ounce serving
  • Mozzarella: 333 milligrams per 1.5-ounce serving
  • Canned sardines: 325 milligrams per 3-ounce serving
  • Cheddar cheeses: 307 milligrams per 1.5-ounce serving
  • Nonfat milk: 299 milligrams per 8-ounce serving
  • Tofu: 253 milligrams per 1/2-cup serving
  • Canned salmon: 181 milligrams per 3-ounce serving
  • Lowfat cottage cheese, 138 milligrams per one-cup serving
  • Turnip greens (cooked): 99 milligrams per 1/2-cup serving
  • Kale (fresh): 94 milligrams per one-cup serving
  • Bok choi (raw): 74 milligrams per one-cup serving
  • White bread: 73 milligrams per slice
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