Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Calcium is key to a sturdy skeleton, and it’s critical for the healthy function of nerves and muscles, including your heart.
“Calcium is so important for the bones and teeth of growing children, but as adults, we sometimes forget how important it is throughout our lifetime,” says endocrinologist Susan Williams, MD.
But when it comes to calcium, it’s actually possible to have too much of a good thing: Calcium can build up to unhealthy levels in your bloodstream.
In fact, high calcium levels (hypercalcemia) can cause a variety of issues that range in severity from headaches to life-threatening heart problems.
But don’t toss your calcium supplements out just yet. Dr. Williams and cardiologist Leslie Cho, MD, explain what happens when calcium levels creep too high — and how to strike a healthy balance.
It’s surprisingly easy to overdo calcium supplements, especially if you consume a lot of dairy or otherwise get plenty of calcium from your food.
Complicating matters further, your calcium levels can also rise from:
Past those birthdays, you should aim for 1,200 mg per day. (For context, a cup of milk or a serving of yogurt each has about 300 mg of calcium.)
A quick glance at an online retailer will show you that most over-the-counter calcium supplements are between 600 and 1,200 milligrams. In other words, depending on the supplement you take, you could exceed your recommended daily amount of calcium before sitting down for breakfast.
Hypercalcemia can be mild, moderate or severe. It can be acute (short-term) or chronic, depending on what’s causing your calcium levels to go up.
Many people — especially those without an underlying health issue causing their calcium levels to be elevated — don’t have obvious symptoms of hypercalcemia. But these symptoms can all potentially point to the condition:
Luckily, hypercalcemia caused by supplements and antacids usually reverses quickly when you stop taking them, Dr. Williams says. Untreated, though, long-term hypercalcemia can be serious — even life-threatening.
One of the primary organs impacted by high calcium levels is your heart. For example, maybe you’ve heard that consuming too much calcium can increase your risk of a heart attack. According to Dr. Cho, coronary artery disease strikes when something blocks the arteries that deliver blood to your heart. Most of the time, that something is atherosclerosis — fatty deposits called plaques that glom onto the walls of the arteries. Plaques in the coronary arteries can lead to heart attacks and stroke.
But plaques aren’t just lumps of fat and cholesterol. Healthcare providers now know that calcium can also collect in those deposits.
“Calcium builds up in the arteries as you age,” explains Dr. Cho.
The good news is providers can actually see it using a calcium-score screening (a type of CT scan that spots calcium in the arteries).
“The calcium lays on the plaques in the arteries, so when we see it on the scan, it serves as a marker for the presence of plaques,” Dr. Cho says.
In older people, it’s common to have a lot of calcium in the arteries, she adds. But in middle-aged adults, it can signal greater plaque buildup — and the need for closer monitoring or more aggressive treatment for atherosclerosis.
But the research on the relationship between high calcium levels and coronary artery disease remains inconclusive. One study found people who had high calcium intake had less — not more — calcification in their coronary arteries. But that was mostly true for people who got calcium from their meals rather than pills. There were also hints that supplements might increase calcium deposits in the arteries. While the findings are fuzzy, there’s one valuable takeaway for anybody looking to protect their ticker: Choose calcium-rich foods over supplements whenever you can.
Additional highly absorbable sources of calcium include:
Aside from focusing on your food choices and being mindful of what supplements you take, how else can you make sure you’re getting enough calcium without going overboard?
You’ve probably heard that it’s important to speak to your doctor before taking a new supplement. Calcium is a great example of the reason why you should take that advice. We all need calcium, and supplementation is common, but we don’t all need the same amount—or even the same kind. And — as you now know — supplementation can be dangerous for some people.
Some prescription medications (like thiazide diuretics and lithium) and conditions (like hyperparathyroidism or lung cancer) can disrupt the balance of calcium in your system, causing hypercalcemia. Your doctor can review your medical history and prescriptions to find out if you’re at risk. It’s equally important for your doctor to know about any other supplements you’re taking.
Vitamin D, for example, helps your body absorb calcium — but, as we know — absorbing too much calcium is dangerous. It’s important, then, to know your vitamin D levels before starting a calcium supplement. You need to be similarly cautious if you take high doses of vitamin A.
This is also why scheduling a regular check-up is important. Most physicians check calcium and vitamin D levels during routine blood tests that you get in an annual exam.
There’s no denying the importance of calcium to our health and well-being. It’s one of the first minerals we learn about growing up because it helps us grow up. For many of us, calcium supplementation is an important tool in our quest to get and stay “big and strong.”
But that doesn’t mean calcium supplements are right for everybody — or that there’s no such thing as too much calcium. Overdoing it with supplements can undermine calcium’s benefits, and even make you sick. That’s why it’s important to speak with your doctor before you integrate a supplement into your daily routine. With their help, you can be sure you’re getting the right kind (and amount) of this mighty mineral.