Could You Have a Calcium Deficiency?

You have more calcium in your body than any other mineral, and 99% of it is stored in your bones and teeth. This means consuming enough calcium is critical for keeping your bones and teeth strong, especially as you age. Calcium is also important for your nerves, heart, and muscle function. The current recommended daily allowance (RDA) for women and men is 1,000 mg to 1,300 mg, depending on your age. By staying within these limits, you’ll be on your way toward maintaining healthy bones and teeth and warding off osteoporosis. But if you don't drink milk or eat dairy products, could you be at risk for a calcium deficiency?

A true calcium deficiency, or hypocalcemia, usually has nothing to do with diet. Instead, blood levels of calcium become too low as a result of taking certain medications and medical conditions (more on this later).

Dietary calcium deficiency—when you're not taking in enough calcium from food and beverages—is very rare. “I rarely ever see a healthy individual with low calcium,” says Lynn Mack, MD, an endocrinologist at the University of Nebraska Medical Center in Omaha. “Most people can get enough calcium by eating a variety of foods rich in calcium.”

Calcium inadequacy is more common, which is when someone's dietary intake of the mineral is lower than recommended. This can lead to health problems like osteoporosis over time.

Some types of medication can cause hypocalcemia by reducing calcium stores or making it more difficult for the body to absorb calcium. One category of medication is diuretics, which increase how much calcium is passed out of the body through urine. Certain antibiotics and antiseizure medications can also lower calcium stores. Proton pump inhibitors (PPIs), which are used to combat stomach acid, don’t cause hypocalcemia, but they could reduce absorption of calcium, says Dr. Mack. If you are taking a PPI and don’t get enough calcium from food, you may need to take a calcium citrate supplement such as Citracal, which doesn’t need stomach acid to be absorbed, she adds.

Problems with the parathyroid glands, which are located on the thyroid in the neck, can affect blood calcium levels. These four glands produce parathyroid hormone (PTH), which helps your body maintain appropriate balance of calcium and phosphorus in the blood. If you’re not producing enough PTH—called hypoparathyroidism, which may be caused by an injury to the gland, a genetic condition, or an endocrine disorder—calcium levels can decline. (If you have too much PTH, on the other hand, then your blood calcium rises.)

Kidney dysfunction can also bring down calcium levels; excess calcium is excreted in urine, which affects the kidneys' ability to activate vitamin D.

There are four groups that are most at risk for calcium inadequacy:

Postmenopausal women: During and after menopause, women produce less estrogen, which in turn decreases calcium absorption and increases bone resorption (the breakdown of old bone). This can lead to osteoporosis. As you approach menopause, talk to your doctor about whether you should increase the amount of calcium-rich foods in your diet. The RDA for adult women through age 50 is 1,000 mg, and 1,200 mg after that.

Women with amenorrhea: Amenorrhea is a condition in which menstrual periods stop (or never start) due to low body weight, a hormonal imbalance, stress, or other causes. Women who don't get a period have reduced circulating estrogen levels, which can mess with calcium balance.

Vegans and people who are lactose intolerant: Dairy is the top source of calcium in most diets, so if you avoid those products, you may not be getting enough of the mineral. Loading up on plenty of non-dairy calcium sources, such as collard greens and broccoli, may help offset this.

There’s an important connection between calcium and vitamin D. “Vitamin D is the key ingredient to allow the gut to absorb calcium,” says Dr. Mack. “So if you are vitamin D deficient, you don’t efficiently absorb calcium.”

Luckily, vitamin D is found in many foods, such as fatty fish (salmon, tuna, mackerel are all great sources), as well as fortified foods, including cereal, milk, and some types of orange juice. Your body also makes vitamin D after you’ve been in the sun, which makes a little exposure every day important (with plenty of SPF, of course).

If you aren't eating enough calcium-rich foods and have a calcium inadequacy, then you won't experience any symptoms. Symptoms of hypocalcemia, on the other hand, can vary and depend on what is causing the deficiency, how severe it is, and other individual factors, according to the National Osteoporosis Foundation. Some people have no symptoms, while others may experience a variety of symptoms, such as muscle cramps or spasms, numbness, tingling sensations, poor appetite, or seizures. In addition, symptoms of related vitamin D deficiency can include achiness or tenderness in the bones, says Dr. Mack.

A simple blood test can determine if you have low calcium levels. Your doctor might suggest a test if he or she thinks your levels are low due to parathyroid or other health problems. There are two tests: one measures ionized calcium, but the test can be expensive and readings aren’t always accurate. The other measures total calcium. “It’s what is used by almost everyone to look at the calcium level,” explains Dr. Mack. If tests show a deficiency, your doctor will try to determine the cause and then decide whether or not you need supplements.

The good news is that a calcium inadequacy can be corrected simply by ingesting more calcium and making sure you’re also getting enough vitamin D. "It’s better to get calcium through diet," says Howard A. Selinger, MD, chair of family medicine at the Frank H. Netter MD School of Medicine at Quinnipiac University in Hamden, Conn. The main sources are dairy products such as milk, low-fat cheese, and yogurt, as well as some fruits and veggies. Many foods have added calcium, including soymilk, bread, and some kinds of bottled water. And make sure you’re also filling your plate with plenty of vitamin D-rich foods, such as spinach and other deep-colored vegetables. “We say the darker the green, the better for you,” says Dr. Selinger. If you’re concerned that diet won’t be enough, speak to your doctor about whether or not you need calcium or vitamin D supplements.

When a person has hypocalcemia, a doctor may recommend calcium and vitamin D supplements, and will also work to treat the underlying condition causing it.

There is such a thing as too much calcium, which is called hypercalcemia. You can consume too much calcium through supplements, but certain health problems can cause your body to develop excessive calcium stores, as well. Those problems include overactive parathyroid glands, certain cancers, immobility, medications, and hereditary factors. Signs of excessive calcium are nausea, vomiting, confusion, and fatigue. More serious symptoms can include problems with your kidneys, weakened bones, arrhythmia, or even severe nervous system problems like dementia and coma.