Podcast Episode 187 – Do Calcium Supplements Increase the Risk of Cardiovascular Disease?

Key Topic

Today, we’re tackling a question we often hear from clients: Do calcium supplements increase the risk of cardiovascular disease?

Since this is a common concern when we recommend calcium supplements, we thought it would be helpful to dedicate an episode to exploring this topic in depth.

Proposed Mechanism

There are a few proposed mechanisms but the main one is:

Elevated calcium levels from supplements might contribute to calcium deposits in blood vessels, which is a factor for heart disease.

Evidence: Part 1

We are fortunate that there actually is a lot of evidence looking at this.
So instead of going through individual studies, we will start with the most relevant review.
It is a 2021 meta-analysis of clinical trials, featuring 13 double blinded RCTs and a sample size of over 40,000 people.
The finding was that there was actually a small increased risk of cardiovascular disease. Specifically in healthy postmenopausal women the increase was around 15%.

Evidence: Part 2

There are 5 similar reviews looking at the topic. Of those 5, three of them found a small increased risk and 2 found no difference.
So it’s not exactly clear cut. But a safe interpretation is that there is a small increased risk.

Dietary Calcium

At this stage it only appears to be a risk if it is in supplemental form
From what we’ve seen, dietary calcium doesn’t increase risk
Some of the reasons why could be:

Dosages in a single sitting are often smaller.
Associated nutrients such as magnesium, phosphorus and vitamin K might reduce vascular calcification.
Absorption might be slower due to integration with other nutrients in food. Calcium levels in the blood rise slower due to this.

Fractures

Since there is a risk associated with calcium supplements, it’s also worth exploring the benefits.
The most common benefit proposed is a reduced risk of fracture, but that evidence is actually weaker than many would expect.
Example: A 2017 meta-analysis covering 33 RCTs, including more than 50,000 participants over the age of 50 looking for calcium and vitamin D supplementation found no reduction in fracture risk.
Note: Similarly sized research looking at the same demographic found a 0.5-1.5% increase in bone mineral density.
That increase in bone mineral density is likely too small to make much difference for fracture risk. But it’s worth acknowledging particularly because in that age group most people have a DECREASE in bone mineral density each year.
Some people also will benefit more than others e.g. low dietary intakes being addressed are more likely to see benefit.
But calcium is still only one variable among many for BMD.

Vitamin K

We’ve previously done a podcast on vitamin K2 talking about how when supplemented in isolation or alongside vitamin D, it has led to reductions in cardiovascular disease risk.
The evidence isn’t overwhelmingly positive, but it’s worth being aware of.
It could have potential to partially offset the issues presented with calcium supplements.

Summary

Calcium supplementation should generally be avoided unless there’s a specific medical reason to take it. A food-first approach is usually preferable, as it allows for a more balanced and natural intake of nutrients. However, in certain cases, calcium supplements can be beneficial if the potential advantages outweigh the associated risks.

Relevant Blogs/Research

Relevant Studies:

Relevant Blog Posts:

Do You Need to Supplement Vitamin K2 Alongside Vitamin D? | Ideal Nutrition