The Truth About Calcium Supplements and Your Heart

Calcium is one of the most commonly supplemented minerals, and yet, there’s been some debate about whether taking calcium supplements could be doing more harm than good—especially when it comes to heart health.  

This article is based on a Dishing Up Nutrition podcast episode about the connection between calcium and heart health titled "Are Calcium Supplements A Heart Risk?" If you prefer to listen or watch...both the podcast audio and video are available at the end of this article. 

The Role of Calcium in the Body 

First, it’s important to understand that calcium plays a vital role in many bodily functions. While most people associate calcium with strong bones, it’s also crucial for muscle contractions, nerve signaling, blood clotting, and even the release of hormones like insulin. Calcium is also involved in relaxing blood vessels, which plays a role in blood pressure regulation. So, it’s doing a lot more than just keeping our bones strong. 

Additionally, 99% of the calcium in our bodies is stored in our skeleton. Beyond bone maintenance, it plays a critical role in hormonal secretion and the healthy functioning of our muscles, nerves, and heart. 

Calcium and Heart Health: What Does the Research Say? 

Over the past couple of decades, there has been some concern that calcium supplements—especially in high doses—could be linked to an increased risk of heart disease. Some studies suggest that large doses of calcium supplements may contribute to calcification of arteries, which is a risk factor for heart disease. However, the data isn’t entirely consistent. 

For example, a 2021 meta-analysis published in Nutrients looked at data from over 40,000 postmenopausal women and found that supplementing with 1,000 mg or more of calcium per day increased the relative risk of cardiovascular disease by about 15%. Another study published in Diabetes Care found that daily calcium supplementation was associated with a higher risk of cardiovascular disease in people with diabetes, but not in those without diabetes. And a 2013 study in JAMA Internal Medicine reported that long-term calcium supplementation was linked to a 20% increased risk of cardiovascular disease in middle-aged men, but not in women. 

In short, some studies show a potential risk, while others find no clear link. One important thing to note: most studies do not show a link between dietary calcium (from food) and increased heart disease risk. So that’s a big takeaway—getting your calcium from real food sources seems to be the safest option. 

Where You Get Your Calcium Matters 

Most of the concerns around calcium and heart disease come from studies looking at calcium supplements rather than dietary calcium intake. When we get calcium from food, it’s balanced with other minerals like magnesium, vitamin K2, and phosphorus, which all play a role in how calcium is used in the body. 

Here’s a great list of the best sources of dietary calcium we recommend adding to your own favorite recipes or dishes: 

If you’re getting plenty of dietary calcium from these foods, you may not even need to be taking calcium supplements. 

However, be cautious with fortified foods like certain cereals, orange juice, and non-dairy milk alternatives, as they are often fortified with calcium carbonate, a poorly absorbed form of calcium that may contribute to arterial calcification.  

Reading labels and choosing whole, unprocessed calcium-rich foods is the best way to ensure you're getting dietary calcium in a form your body can use effectively. 

If You're Taking Calcium Supplements, Consider These Factors 

If you do choose to take a calcium supplement, there are a few things to keep in mind: 

Type of Calcium Matters  

Calcium carbonate is the most common form found in supplements, but it requires adequate stomach acid for intestinal absorption. It’s also more likely to contribute to arterial calcification.  

Instead, opt for more bioavailable forms such as calcium citrate, Di-Calcium Malate (DimaCal), or MCHA (Microcrystalline Hydroxyapatite), which more closely resembles the natural calcium found in bones. 

Here’s how to check: flip the bottle over and if it says “calcium carbonate” or “coral calcium” on the ingredient label, it is time for an upgrade. 

Dose and Timing Are Important  

Large, single doses (1,000 mg at once) may be more problematic. Instead, split your calcium intake into smaller doses throughout the day. 

Calcium Needs Other Nutrients  

Vitamin D, magnesium, and vitamin K2 help direct calcium to where it’s needed (bones and teeth) rather than allowing it to accumulate in arteries. Many studies do not account for whether people are getting enough of these key cofactors. 

Look for vitamin D3 on the label of your calcium supplement, because research shows that vitamin D helps calcium get absorbed from the intestinal tract. If you're taking calcium but you don't have enough vitamin D, then you're not able to fully absorb the calcium that you're taking. 

Final Thoughts 

The research on calcium supplements and heart health is still evolving, but if you’re concerned, the safest approach is to get as much of your calcium as possible from whole foods (dietary calcium). If you do choose calcium supplements, choose a well-absorbed form of calcium, take it in smaller doses, and pair it with vitamin D, magnesium, and vitamin K2 to support proper calcium metabolism.

Recommended Supplements 

For those looking for a high-quality calcium supplement, we recommend NutriKey Activated Calcium, which includes highly absorbable forms of calcium along with the necessary cofactors for optimal utilization. For more comprehensive bone support, Key Osteo Plus is our Cadillac bone supplement, designed specifically to help form new bone and includes calcium, magnesium, vitamin D, and K2.