What Happens to Your Body When You Take Too Much Calcium

Calcium is the most abundant mineral in your body. You probably already know you need it for strong bones and teeth. But calcium has lots of other important jobs, like helping your nerves and muscles function properly, enabling your blood vessels to contract and relax and helping you secrete hormones. 

So if some calcium is good, more must be better, right? Not so fast. It is possible to have too much of a good thing. Excessively high blood calcium levels, also known as hypercalcemia, can lead to weak bones, digestive problems, kidney issues and many other symptoms, ranging from mild to serious. 

Can consuming too much calcium cause hypercalcemia? To find out, we took a look at the latest science and spoke with experts to learn more about what happens to your body when you overload on calcium.

What Is Hypercalcemia?

Samantha MacLeod, RD, a registered dietitian with Fresh Communications, puts it simply: “Hypercalcemia is the state of having too much calcium in the blood.” The average adult requires about 1,000 milligrams of calcium per day. However, you’ll need more if you’re older (1,200 mg per day for women 51 and over and men past 71). Dairy products like milk, cheese, yogurt and kefir are the richest sources of calcium in our diets. However, if you don’t eat dairy foods, you’ll also find plenty of calcium in sardines and salmon with bones and calcium-fortified soy milk, nut milks, tofu and orange juice (check the label to know for sure!). You can also get smaller amounts from broccoli, edamame and calcium-fortified cereals. 

So, if you need roughly 1,000 mg of calcium a day, it’s easy to assume that consuming more can lead to high blood calcium levels. However, according to the National Institutes of Health, it’s completely safe for healthy adults to consume up to 2,500 mg of calcium daily (2,000 mg for those over 51).  Why the gap? Too much calcium can be extremely dangerous (more on this soon). And your body knows it! So, it works hard to keep blood calcium levels in a very tight range. 

If you’re wondering how it’s able to do this so efficiently, you can thank your parathyroid glands. These four small glands that sit behind the thyroid gland in your neck produce a hormone called parathyroid hormone (PTH). Together with vitamin D, PTH carefully regulates calcium levels in your body. Calcium levels in your blood usually rise when your parathyroid glands aren’t working properly, so it’s unlikely to be an issue unless you have certain underlying health conditions. 

It can also be helpful to know that most of us don’t consume enough calcium in the first place. Considering you’d have to drink two quarts of milk to exceed the 2,500 mg upper limit, it’s unlikely that any of us are getting too much calcium from naturally calcium-rich foods. Supplements, however, might be another story. That’s because they often contain larger amounts of calcium than you’d get from foods.  So, their calcium can add up quickly, especially if you’re taking them in addition to a calcium-heavy diet. 

Symptoms of Hypercalcemia

Hypercalcemia can be tricky to spot because it often doesn’t cause symptoms, at least not in the early stages. “Mild cases of hypercalcemia oftentimes are asymptomatic,” says Sarina Bains, M.D., an endocrine surgeon with Atlantic Medical Group at CentraState Medical Center, part of Atlantic Health System. “Moderate to severe cases of hypercalcemia may cause fatigue, weakness, nausea, vomiting, constipation, excessive thirst and frequent urination, trouble concentrating, memory problems, bone and muscle pain, bone fractures and kidney stones.” It may also lead to muscle weakness and twitching. Because hypercalcemia can impact the brain, it may make you feel confused. At the extreme, hypercalcemia may even cause dangerous heart arrhythmias. Alarming as that may sound, it is extremely rare, striking only 1% to 2% of people, and nearly all of them have medical conditions predisposing them to this condition.

Causes of Excess Calcium

“The most common cause of hypercalcemia is primary hyperparathyroidism [PHPT], where the parathyroid glands, which are located in the neck, are overactive,” says Bains. “This produces too much parathyroid hormone, which can cause calcium levels to rise.”  In fact, 90% of people with hypercalcemia either have PHPT or a cancer that impacts parathyroid function.,

However, hypercalcemia can also have other causes, like these:

• Excessive use of calcium or vitamin D supplements
• Certain cancers, particularly lung or breast cancer 
• Some medications, such as lithium or thiazide diuretics
• An overactive thyroid gland
• Kidney disease
• Genetic conditions that impair the body’s ability to regulate calcium
• Infections and illnesses, such as sarcoidosis, tuberculosis and Paget’s disease

Health Risks and Complications

While too much calcium from foods is unlikely to be an issue, excessive supplementation could potentially spell trouble. According to the National Kidney Foundation, calcium supplements may increase the risk of kidney stones in people who are predisposed to calcium oxalate stones.  

As for hypercalcemia, complications from this rare condition are unlikely. Yet, they can happen, especially without treatment. In addition to kidney stones, some severe long-term health risks associated with hypercalcemia include kidney failure, osteoporosis, an irregular heartbeat and even life-threatening arrhythmias, says Bains.

Other complications may include: 

• Pancreatitis
• Peptic ulcers
• High blood pressure
• Depression
• Confusion or difficulty concentrating
• Bone fractures

Diagnosis and Treatment 

“The best way to diagnose hypercalcemia is via a blood test measuring the levels of calcium, parathyroid hormone and vitamin D,” says Bains. Treatment may be more complex. “Treatment will be aimed at whatever is causing your hypercalcemia,” she adds. “Treatment depends primarily on the cause of hypercalcemia. If hyperparathyroidism is the underlying cause, the patient will likely benefit from a parathyroidectomy, the surgical removal of one or more parathyroid glands.”

It’s important to uncover the underlying cause of hypercalcemia and treat it appropriately. The majority of people who have mild PHPT or hypercalcemia due to a treatable cause have a good prognosis. “If hypercalcemia is secondary to an underlying cancer, the cancer should be managed in order to control hypercalcemia,” says Bains. “Excessive calcium intake or vitamin D toxicity are generally treated by stopping the supplement and increasing fluid intake.” Depending on the cause and degree of hypercalcemia, additional treatments may include IV fluids, steroids, diuretics, medication to inhibit bone breakdown, hormonal treatments to lower calcium levels and possibly dialysis. 

As rare as hypercalcemia is, if you think you might have it, don’t ignore it. “A person should see their primary care provider if they suspect they may have hypercalcemia,” says Bains. “Untreated hypercalcemia can lead to severe complications, therefore early diagnosis and intervention are important.”

The Bottom Line

If you’re worried about consuming too much calcium, it can be helpful to know that few of us consume enough of this mineral to begin with. However, it is possible to get too much calcium from supplements, especially if you’re already consuming a calcium-heavy diet. At the extreme, this may lead to a rare condition called hypercalcemia. 

Hypercalcemia is characterized by high levels of blood calcium and is usually caused by an underlying health condition. However, too much calcium from supplements can lead to kidney stones. So, if you’re taking or considering a calcium supplement, be sure to speak with your doctor. But if you’re healthy and your diet is packed with naturally calcium-rich foods, keep up the good work!