Practicing healthy habits can get confusing when something that’s supposed to help one medical condition potentially hurts another. This has been the case (and controversy) regarding taking calcium supplements to promote healthy bones.

Some researchers have identified a potential link between taking calcium supplements and increased risk of heart disease and heart attack.

While several analyses have identified potential risks of taking calcium supplements, most researchers conclude that calcium supplementation isn’t harmful. Keep reading to find out what we’ve learned about this debate.

Even researchers have a hard time agreeing on the potential effects of calcium on cardiovascular disease. Studies related to calcium and heart disease have shown conflicting results.

Sometimes, conflicting results are due to studies using different selection criteria. That means they might differ in how they study or define heart disease. For example, some studies included patients who self-reported their heart attacks. Other studies only considered those who got an official diagnosis.

To review the most recent research, we looked at new meta-analysis data. A meta-analysis looks at many studies and combines their results to see if there are patterns. Here are some results from these studies.

  • A 2021 review of studies found that dietary calcium intake of between 700 to 1,000 milligrams a day or a supplementary intake of 1,000 milligrams a day significantly increased a person’s risk of cardiovascular disease and coronary heart disease, which can lead to heart attack. Healthy, postmenopausal women were especially at risk.
  • 2020 research studied individuals for 20 years and found that taking calcium supplements was associated with a lower risk of death from multiple causes. The researchers also found that women (but not men) who took calcium supplements had reduced risks for cardiovascular and all-cause mortality (death from any cause).
  • A 2019 study of more than 130,000 individuals didn’t find a connection between calcium supplements and heart attack. However, calcium supplements paired with vitamin D helped to reduce the risk of heart attack, especially for those already at high risk.

Researchers acknowledge there are challenges to linking calcium supplements with heart disease or heart attack risk. Many of the studies reviewed didn’t specifically relate to this topic, but instead looked at various health habits.

To be clear, researchers haven’t identified how calcium supplements may increase heart disease risk. That doesn’t mean they don’t have some ideas for potential reasons. These include:

  • Oral calcium supplementation can increase the body’s calcium concentrations for some time. Researchers have previously identified that people with a genetic tendency to have higher blood calcium levels are at higher risk of heart disease and heart attack.
  • Higher calcium levels could increase the likelihood that calcifications (hardened deposits of calcium) will build up on the blood vessels. These calcifications cause your blood vessels to not work as well, as blood can’t flow as easily.
  • Excess calcium could affect how well blood clots in the body.

Calcifications in the blood vessels in the heart can build up as “plaque” (not the same as what’s on your teeth, but definitely harmful). This plaque is an early sign of heart disease and increases your risk of heart attack.

Hypocalcemia (too little calcium) can be dangerous too. You can have all sorts of symptoms that include muscle cramping, seizures, breathing problems, difficulty thinking, and increased risks for congestive heart failure. A balance is definitely necessary.

Calcium is a mineral naturally present in your bones. As you age, you’re at greater risk of a bone-thinning disease called osteoporosis. If you don’t get enough calcium (about 700 to 1,200 milligrams per day) in your daily diet, your doctor may recommend taking calcium supplements.

Ideally, doctors hope that increasing calcium in your daily diet makes you less likely to get fractures (bone breaks) from osteoporosis. However, when research about calcium supplements and heart attack risk came about, some doctors were hesitant to recommend calcium supplements.

The following are some commonly asked questions about calcium and health.

Should I reduce the amount of calcium in my diet?

In a word, no. Unless you have a health condition where your doctor has specifically told you to reduce daily calcium, you shouldn’t reduce your calcium intake.

Your body needs calcium to complete a number of functions, including building healthy bones. Low calcium intakes and levels may also increase your risk of death.

What is the recommended daily amount of calcium I should have?

The International Osteoporosis Foundation recommends different calcium intakes based on your age. As you get older, your body is less able to absorb calcium into your bones. This means that you need more calcium as you age.

AgeCalcium Recommended Daily Intake (mg/day)
0 to 6 months200
6 to 12 months260
1 to 3 years 700
4 to 8 years1,000
9 to 13 years1,300
14 to 18 years1,300
19 to 50 years1,000
51 to 70 yearsWomen: 1,200 Men: 1,000
More than 70 years1,200

What are some nondairy calcium sources?

Dairy products don’t have to be your only daily calcium source. Other foods that have calcium include:

  • bok choy
  • broccoli
  • curly kale
  • nuts, such as almonds
  • tofu that’s calcium-set

Food manufacturers may also fortify (add) calcium into other foods, such as bread, cereals, and juice.

The research will continue on calcium supplementation and heart attack risks. However, no research has definitively proven that calcium supplements are harmful, and some studies have found positive heart-health effects associated with taking them.

Talk with a doctor about how calcium supplements could benefit your health and if you should have any concerns given your health history.