The Dangers of Too Much Calcium

Did you know that you can take too much calcium (Ca2+) which can cause serious medical disorders?

If you're over 50, your doctor may have advised you to take 1,200 milligrams of calcium a day, plus vitamin D to protect your bones and help to prevent health related problems like, heart disease, cancer, and many other medical disorders.

But did you know that you can take too much calcium (Ca2+) which can cause serious medical disorders?

Since 2006 the University of Auckland School of Medicine Foundation has tested women taking calcium, without vitamin D, to see if it raises the risks of heart attacks.

What they found was 30% of those tested taking 1 gram of calcium, were more likely to have a heart attack than those taking a inactive placebo. Vitamin D was not included in this study because it is being tested separately.

Many feel that the exclusion of D may play an important role in the occurrence of heart attacks, so if this information has you concerned or confused, speak with your doctor about the amount of calcium you take.

The study, published in the British Medical Journal, did not mention the safer amount of calcium to take that might stave off these heart problems, so we need to wait for further studies on this question and others, or you can get your physicians' advice.

The take away information from this study is calcium rich foods are the safest way to get your daily requirements. Calcium from food is absorbed more slowly and does not produce these heart related problems.

There are other medical concerns related to excess calcium, which we discuss below, so it's important to discuss the current RDA on calcium with your doctor to see if you might be taking too much

One of the main disorders caused by too much calcium is hypercalcemia. Usually hypercalcemia occurs when one or more of your parathyroid glands is over-active, or if you have an adenoma (benign parathyroid tumor).

Other common causes of hypercalcemia are: cancer, some medications, taking calcium and vitamin D and other medical disorders, listed below.

How Should You Take Your Calcium?

Most of us are told to get the majority of calcium from our diet and then make up the difference of our daily requirements with a supplemental form of this mineral.

To calculate this, you'd add up all the calcium in your diet, and then add to that whatever remains to total 1,200 milligrams of supplemental calcium.

Your doctor may recommend more, or much less, but this is the calcium recommendations from the National Osteoporosis Foundation for those over 50. Also, to simplify this process, you can get a list from your doctor that helps you to calculate your daily Ca2+ from food.

Also discuss this new finding to see if taking a much lower amount of calcium is more beneficial for your heart health to protect against heart attack, stroke and kidney stones among other health problems listed below.

We have many fortified foods now that include Ca2+ and vitamin D, so it's important to know exactly how much you are getting - through your diet - before you add supplements to it so you don't take way over the recommended daily allowance (RDA).

We get many questions about Ca2+, and those who are taking a large dose, well over the RDA, are invariably not calculating their dietary intake in addition to their supplement which can get us into some trouble.

What Is Hypercalcemia and How Is It Treated?

Hypercalcemia is a diagnosis given to those with excess serum (blood) calcium levels. If you've had a test for this and it was above the reference range (normal range), it may be a good idea to repeat it to be sure that there were no lab errors.

According to the American Academy of Family Physicians:

Hypercalcemic crisis is a life-threatening emergency. Aggressive intravenous rehydration is the mainstay of management in severe hypercalcemia, and antiresorptive agents, such as calcitonin and bisphosphonates, frequently can alleviate the clinical manifestations of hypercalcemic disorders.

One must also diagnose primary hyperparathyroid disorder and any other secondary cause of hypercalcemia, since these disorders can be treated. If the cause arises from an over-active parathyroid gland (hPTH), surgery is generally considered to remove the gland that is causing this.

Since we have four parathyroid glands, it's important to find out which is the malfunctioning one, or if all of them are causing excess hormone release.
Treatment of hyperparathyroid would start with a diagnosis obtained through a sestamibi scan or an ultra-sound of the gland.
Sestamibi scans can give false negative results, so be sure to consider additional testing if the test is negative and you still have high PTH/Ca2+ levels and symptoms.
If one of these tests finds an adenoma or over-active parathyroid gland, then discuss the possible solution to this - with your doctor - which could be a minimally invasive parathyroidectomy surgery (MIP or MIRP-radio guided).
These types of surgeries are best done by an Endocrine specialist who has many years of experience with this procedure, and access to the minimally invasive surgical equipment.

Tests you should have to measure your blood Ca2+ levels:

  • 24 hour urine Ca2+ test

  • Serum (blood) total Ca2+ test

  • Ionized Ca2+ test (if you have thyroid, cancer or parathyroid problems)

  • Intack Parathyroid test (iPTH)

What Other Medical Disorders, Causes and Symptoms Arise From Too Much Calcium?

Medical Disorders

  • Pancreatitis

  • Polydipsia

  • Polyuria

  • Nephrocalcinosis

  • Osteoporosis

  • Anorexia


  • Genetic disorders

  • Endocrine disorders

  • Medications

  • Family history

  • Hypertension

  • Vitamin D

  • Hyperparathyroidism

  • Malignancy

  • Nephrolithiasis

  • Hypercalciuria


  • Impaired mental concentration

  • Confusion

  • Corneal calcification

  • Fatigue

  • Muscle weakness

  • Abdominal pain

  • Cardiac arrhythmias, Heart attack

  • Nausea

  • Vascular calcification

  • Constipation

  • Short QT interval

  • Peptic ulcer (rare)

  • Bone pain (in hPTH and malignancies patients)

  • Tetany (muscle contractions)

To see a full list of symptoms, causes and medical disorders related to hypercalcemia go to the American Academy of Family Physicians website on hypercalcemia.

So we know that Ca2+ is a very important vitamin necessary for good bone and general health, but it can be over-used with all the fortified foods we have now, and for those not calculating their dietary intake in addition to the amounts you take through supplements. Even if you are taking the correct amount of Ca2+, have your doctor check you Ca2+ levels, with the tests above.

If you have any of the above symptoms, medical disorders, or causes be sure to speak with your health care provider about testing for Ca2+ levels.

Also, if you do have hypercalcemia, be sure to check with your doctor on the amount of vitamin D you should take on a daily basis.

We need to have this discussion with our provider - about vitamin D - because vitamin D can elevate our Ca2+ (calcium) levels.

For a list of calcium-rich foods see this link from the National Institutes of Health.

Pam Flores
Meet Our Writer
Pam Flores

Pam wrote for HealthCentral as a patient expert for Osteoporosis.