Are Calcium Supplements A Heart Risk? - Ask a Nutritionist

Transcript:

Hello, and welcome to Dishing Up Nutrition's "Ask a Nutritionist" podcast brought to you by Nutritional Weight & Wellness. My name is Leah Kleinschrodt, and I'm a Registered and Licensed Dietitian. We are thrilled to be celebrating 20 years on air, discussing the connection between what you eat and how you feel.

Thank you for your support and listenership over the years. And if you've enjoyed this show, let us know by leaving a review and a rating on your favorite podcast platform, because your feedback helps others find these important real food messages. So on today's show, I will be answering one question that we received from one of our Dishing Up Nutrition listeners.

This listener asks, “Is there any truth to the relationship between calcium supplements and heart disease?” So super interesting question, and it's an important question to consider. Calcium supplements are very popular. If you go to any supermarket or supplement store, or you do a quick search on Amazon, you're going to find yourself facing a wall of calcium supplements to choose from.

What roles does calcium play in the body?

Most of the clients I see in clinic are taking calcium supplements, or they're taking calcium in high amounts because they're women. And most of the time it's because we're looking to preserve our bone health or to prevent osteoporosis. Calcium does play other roles in the body too. And I just want to highlight those.

They're important for proper muscle contractions, proper nerve signaling, relaxing our blood vessels. And it also helps in the release of some important hormones, insulin being one of them. So it's not just all about bones. Calcium has other important roles also. And in clinic, we see calcium can be helpful for muscle cramps or Charley Horses, especially if we're not quite getting to the crux of the problem with magnesium and calcium can be helpful for lowering blood pressure.

That's not all to say too, in the last 10, 15, maybe 20 years or so, there has been some concerns and some chatter in the literature about are we doing ourselves a disservice on the cardiovascular side of things in the process of trying to protect our bones? So that's what we kind of want to dig into a little bit more today.

Calcium recommendations & sources

So let's just do a quick rundown of calcium, and where do we get it from the diet? So calcium recommendations. The recommendations for adult men and women are 1,000 milligrams of calcium per day. And if you're a post-menopausal woman, then we're looking at 1,200 milligrams of calcium a day. Calcium intake in the United States primarily consists of dairy products.

That's about three fourths of calcium in our diets here in the U.S. But we also get calcium in some of our dark leafy greens. So think spinach, kale bok choy, arugula, things like that; almonds, some of our nuts and our seeds, bone in canned fish. These are other real food sources of calcium.

And then calcium is also fortified into different foods and beverages; things like orange juice, almond milk, tofu, different grain products. So think tortillas, bread, cereals, things like that. And fortified means that calcium has been added to that food where calcium wouldn't otherwise have been found in that food. According to the national database that tracks nutrient intake for the United States, the average man consumes about a thousand eighty three milligrams of calcium per day from food alone, and for women that number is about eight hundred and forty two milligrams of calcium per day.

And let's just remember this is for the average American adult, so likely they are eating a little bit more of a standard American diet, which is more likely to include some of those fortified calcium products, like the juices and the breads and the cereals. So for the most part, according to those numbers, most adult men and women are meeting or at least getting close to those recommended amounts of a thousand milligrams of calcium a day. So there's, there is nuance there, but if we're just kind of pulling those numbers, that's what we're looking at.

Is there a connection between calcium supplements & cardiovascular disease?

Now, I did take a look at some of the recent research calling into question calcium supplements and cardiovascular disease. I don't want to bore anybody. This part gets a little bit nerdy, so if you want to skip forward 15 or 30 seconds or so, you certainly can.

But just to highlight some of the studies that are out there, there was a meta-analysis that was published in the journal, Nutrients, in 2021 that looked at 13 randomized control trials and this involved over 40,000 healthy post-menopausal women. So this was a an analysis that was looking at a bunch of different studies and trying to pull together what the consensus was.

This review concluded that supplementing with a thousand milligrams or more of calcium increased the relative risk of cardiovascular disease by about 15%. There was a study that was published in the journal, Diabetes Care, that, this was just published earlier this year, that showed that daily supplementation with calcium was associated with a higher risk of cardiovascular disease in subjects who had diabetes, but not people who didn't have diabetes.

And then this goes back a few years back to 2013, but there was a study published in JAMA Internal Medicine that showed that long term calcium supplementation was associated with a 20 percent increased risk of cardiovascular disease in middle aged men but not in women. So if we're kind of looking at this from a 30,000 foot view, you can kind of see the data is a little bit all over the place.

So again, it's an important question to be looking at, but there's also a lot of nuance that needs to be flushed out. So before I continue on and talk about some of those nuance points, I'm going to pause here and take a quick break. When we come back, I'll share more about those nuances of calcium supplementation and just some of my thoughts about the research. So we'll be back in a moment.

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Welcome back. So before break, we were talking a little bit about some of the research that has highlighted some concerns about calcium supplementation when it comes to heart disease and cardiovascular disease. So I just want to take a moment, just share some of my observations and thoughts as being a dietitian now for several years and looking at the research and working with clients in general.

So one thing that came up in the research and most of the studies that I review showed that even if there was a small increase in cardiovascular disease with calcium supplements, by far, these studies showed that dietary calcium intake was not an issue for cardiovascular disease risk.

So that makes the case to say, like, let's try to get as much calcium out of our food as we possibly can, where it is likely balanced out with other important minerals and vitamins and other nutrients. So that is one point to look at. Another to think about is when it comes to these studies and the reviews of these studies, how calcium was given varied a lot depending on which study you looked at.

Some of the studies were dosing calcium in large bolus doses. So think taking like a thousand milligrams of calcium in one fell swoop, which is not an uncommon way to do calcium supplements. Again, if you're looking at the wall of supplements, a lot of times you will see calcium supplements that say you can get a thousand percent of your daily calcium needs just in one capsule or one tablet or one fell swoop.

So there were a few studies where the protocols of these calcium supplements, where they were splitting them up into multiple doses throughout the day. And logically, this makes sense because that's how we would probably do it regularly if we weren't doing calcium supplements where we're getting some calcium in every time we're eating at each of our main meals.

So when we're looking and trying to compare studies that dosed a big bolus of calcium versus studies where the calcium was a little bit more spread out throughout the day, it just shows that it's hard to compare apples to apples when the protocols looked different in a lot of these studies.

Type of calcium matters

On the same note, what kind of calcium was used in these studies also needs to be considered. Most of the studies that I looked at and reviewed were using calcium supplements that used calcium carbonate, while there were a few other studies that looked at some other forms. So maybe they were looking at calcium citrate or calcium gluconate or calcium malate, a little bit lesser known forms of calcium.

So again, hard to compare apples to apples here. Calcium carbonate is probably the most common form of calcium used in supplements, but the absorption of calcium carbonate is very dependent on how acidic the stomach is. So if we think about how many people walk around out there that have heartburn, they take antacids or some kind of medication to decrease acidity in the stomach kind of calls into question, like how well are we actually absorbing some of our calcium supplements, especially a calcium carbonate, if the acidity in our stomach might not be up to par?

So calcium citrate is less dependent on acidity. The absorption tends to be a little bit better with calcium citrate. And then again, it depends on the different forms. Some are going to have better absorption than others. No one knows exactly the mechanism of how calcium could be problematic for cardiovascular disease, so that's another point to look at. There's a lot of theories out there, but no one has kind of nailed it down and said, this is exactly why calcium is problematic and this is the mechanism as to how it creates cardiovascular disease.

Looking at calcium metabolism among other nutrients

And lastly, one of my biggest thoughts around this is that when we're looking at calcium supplementation, or we're looking at some of these calcium studies in relationship to heart disease, I didn't see any studies that looked at supplementing calcium with also looking at the other synergistic nutrients that we know are involved in calcium metabolism in the body.

So that's kind of a mouthful. But so let's just say again, like say if we're supplementing with calcium, are we also getting an adequate vitamin D? Are we also getting in magnesium? Are we also getting in vitamin K2? And I'm sure there's other nutrients out there as well that I didn't just list, but all of these things are important in where calcium goes in the body, how well it's absorbed, what happens to it once it does get into our body and how do we metabolize it from there?

Vitamin K2 especially is important because that's the one that tells calcium to go to our bones and our teeth and not get deposited into our soft tissues or into our arteries or into our kidneys. So this, in my opinion or my guess, this is why getting calcium from real food may be a better option if you're able to since many of these foods also contain these synergistic nutrients and they work with each other within kind of a food matrix. We don't always understand what that food matrix exactly looks like or how the interplay of these nutrients work. But that's nature's wisdom right there.  

Summary

So, in summary, the jury is still out in general as to truly whether calcium supplements are truly harmful for our heart health, but if we're erring on the side of caution or as a consumer, if we're just trying to do the best we can for our health, I would say if you're going to take a calcium supplement, we're looking to get a more absorbable one form of calcium.

So thinking something like citrate, calcium citrate, or there is a kind of calcium alter called MCHC, which is more of a live bone type of material. Or we're looking at a product that might have a couple different forms of calcium where we're getting maybe two or three or four different kinds of calcium in one supplement.

So we are maximizing or trying to get a variety of calcium into the body. And ideally, we're probably taking that calcium in more divided doses for better absorption versus just popping one tablet and getting your full 1,000 or 1,200 milligrams all in one fell swoop. And it would also likely be favorable to consume your calcium with other important nutrients like vitamin D, like vitamin K2, and with magnesium.

And that is, again, whether it is through food or with supplementation. So those are just some thoughts and just some of the background research on why you might hear that calcium supplementation might be a problem when it comes to heart health. It's, it, the research is out there.

It is not all flushed out, but it is something to pay attention to. So I hope that was helpful. And I want to thank you all again for listening to Dishing Up Nutrition's “Ask a Nutritionist”. And if you found this episode helpful, be sure to leave us a rating or review on your favorite podcast app. If you have a nutrition question for us that you would like us to answer, we have two options for you.

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