Calcium is essential for strong bones, but recent research has raised some questions about its effects on heart health. Many people, especially those who are postmenopausal (have gone through menopause), take calcium supplements to prevent osteoporosis, a disease that weakens bones and makes them more at risk of breaking. However, some studies suggest these supplements may increase the risk of heart disease.

In this article, we’ll explore the evidence and what you should consider when deciding whether to take calcium supplements.

Can Taking Calcium Supplements Cause Harm?

Calcium plays a role in muscle movement, blood clotting, and nerve signaling, but too much from supplements may lead to complications. Some studies suggest that taking calcium supplements may increase the risk of cardiovascular disease (CVD), which is a group of conditions that affect the heart and blood vessels. These studies also reported that calcium can increase the risk of heart attacks and strokes.

One study in Nutrients found that calcium supplements increased the risk of heart disease by 15 percent in healthy postmenopausal women. Another study found that people taking high doses of calcium supplements had greater plaque buildup in their arteries compared to those who didn’t take supplements, which can lead to heart attacks.

How Does This Happen?

Some researchers think this might happen because calcium from supplements enters the bloodstream too quickly, causing a spike in blood calcium levels for a small amount of time. This sudden increase may lead to vascular calcification — calcium buildup in the arteries — which can harden arteries and increase heart disease risk. On the other hand, calcium from food is absorbed more slowly, allowing the body to adjust to calcium levels more easily.

How Strong Is the Evidence?

The evidence linking calcium supplements to heart disease is mixed. Some studies support the connection, while others do not. For example:

• A review of 13 studies showed an increased risk of heart disease and coronary heart disease (a condition where the arteries that supply blood to the heart become too narrow or blocked) among healthy postmenopausal women who took between 700 and 1,000 milligrams of calcium per day from their diet, or 1,000 milligrams per day from a calcium supplement.
• Other research, however, suggests that calcium supplements, when taken in combination with vitamin D, do not increase cardiovascular risk.
• Past research suggests that your body absorbs calcium citrate more efficiently than calcium carbonate. This may lower the amount of unabsorbed calcium left in the blood, which some health experts believe may lower the risk of calcium contributing to plaque buildup in blood vessels.
• A 2020 United Kingdom study included a meta-analysis that found calcium supplements may lower the risk of death from all causes and heart disease — particularly in women. While the study’s cohort data did not show a significant benefit for the general population, the authors noted a possible protective effect for women. More research is needed to confirm these findings.

Given these conflicting results, more research is needed before reaching a definite conclusion about the role of calcium supplements in heart health.

Should You Continue Taking Calcium Supplements?

If you take calcium supplements, you may be wondering if you should stop. The answer depends on your individual health needs. Here are some key factors to consider.

Do You Have Osteoporosis or a High Risk of Breaking a Bone?

For people with osteoporosis or a high risk of breaking bones, calcium supplements may still be necessary. The National Osteoporosis Foundation recommends getting enough calcium through diet first but using supplements if you can’t get enough through your diet. Talk to your doctor about the right balance.

Are You Getting Enough Calcium From Food?

The best way to get calcium is through food. The recommended daily intake for most American adults is 1,000 milligrams daily for ages 19 to 50, and then 1,200 milligrams per day for people over age 50.

Excellent sources of calcium include:

• Dairy products (milk, yogurt, cheese)
• Leafy green vegetables (kale, broccoli, bok choy, collard greens)
• Almonds
• Tofu
• Fortified foods, which are foods with added nutrients (cereals, plant-based milk, orange juice, and soy products)
• Fish with edible bones (sardines, canned salmon)
• Legumes and seeds (chia seeds, sesame seeds, white beans)

How Much Calcium Should You Take if Supplementing?

For people who do need to supplement, health experts recommend keeping doses lower to avoid unnecessary risks. The general guideline is:

• Limit doses to 500 to 600 milligrams at a time, as the body absorbs calcium more effectively in smaller amounts.
• Taking vitamin D with your calcium can help your body absorb it better. This can include 10 to 15 minutes of safe sunshine exposure or 800 to 1,000 international units of a vitamin D supplement.
• Avoid taking more than the recommended amount (total from diet and supplements), as higher doses may lead to muscle problems, kidney problems, constipation, nausea, or heart rhythm changes.

If you can get enough calcium from your diet, you may not need supplements at all. Also, getting your calcium from food may be better, since it’s absorbed slower and naturally, lowering potential risks that can come along with high-dose supplements.

Do You Have Heart Disease Risk Factors?

If you have a history of high blood pressure, high cholesterol, or heart disease, you should be cautious about calcium supplements. Research is conflicting in this area, but most health experts agree that calcium supplements do not affect the risk of heart disease. Instead, they may suggest consuming more calcium through food or taking smaller supplements throughout the day rather than a large dose all at once.

How To Safely Get Enough Calcium

If you need more calcium, consider these safe and heart-healthy approaches:

• Prioritize calcium in food. It is absorbed more effectively and does not spike blood calcium levels.
• Limit calcium supplements to the minimum necessary. Aim for no more than 500 to 600 milligrams per day if needed.
• Stay active. Weight-bearing exercises like walking, jogging, and strength training help maintain strong bones and improve heart health.
• Choose the right form of calcium. Calcium citrate is often better absorbed than calcium carbonate, especially if you have existing health conditions.

Take Them or Toss Them?

The debate over calcium supplements and heart disease risk is ongoing. While some studies suggest a link, others do not. The safest approach is to get calcium from food whenever possible and to use supplements only when necessary. Timing and dosage play a large part in how your body absorbs the calcium.

If you have concerns about your heart health or osteoporosis, talk with your healthcare provider to come up with the best plan for you.

Talk With Others Who Understand

MyHeartDiseaseTeam is the social network for people with heart disease and their loved ones. On MyHeartDiseaseTeam, more than 62,000 members come together to ask questions, give advice, and share their stories with others who understand life with heart disease.

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