Calcium: How Much You Need and Why

Calcium gets loads of attention for keeping your bones strong and healthy, but let’s give the mineral all the credit it deserves — because that’s just one of many important roles it plays in your body.

The calcium in your system also helps keep your heart beating, muscles working and nerves firing, among other things. It may offer protection against cancer and high blood pressure, too.

Impressive, right? Well, those are just the highlights. Let’s turn to registered dietitian Beth Czerwony, RD, LD, to learn more about what calcium does, how much you need and how to get it through your diet.

What is calcium?

Calcium is an alkaline earth metal on the periodic table of elements. It's listed under the symbol Ca with an atomic number of 20. (If this sounds familiar, kudos on paying attention in middle school science class.)

But this mineral isn’t just out and about on the planet. It’s also inside of you. In fact, calcium is the most abundant mineral in your body.

More than 99% of the calcium in your body resides in your bones and teeth to give them strength and structure. The rest can be found in your muscles and tissues and circulating through your blood.

But don’t underestimate the importance of that other 1% of calcium in your body. “It’s a small amount,” says Czerwony, “but it does a lot of good.”

How much calcium do you need?

Your body can’t produce the calcium it needs on its own. You take it in through what you eat and drink or from supplements. (This is why calcium is considered an “essential nutrient” in your diet.)

So how much calcium is the right amount for you? That’s a more difficult question to answer than you might expect. Guidance on calcium intake varies around the world due to dietary, genetic, lifestyle and geographical reasons.

In the United States, the target for calcium consumption is generally set higher.

It’s recommended that adults in the U.S. ages 19 to 50 as well as those ages 71 and older aim to take in 1,000 milligrams (mg) of calcium per day, according to the National Institutes of Health (NIH).

From the ages 51 to 70, the recommended daily amount depends on your sex assigned at birth. That’s namely because of bone mass changes during menopause, which people assigned female at birth (AFAB) typically experience in their early 50s.

Here are calcium recommendations by age from the NIH:

Keep in mind that these recommendations don’t account for bodily differences like weight, height and overall health. “It’s always best to ask a healthcare provider how much you need,” Czerwony advises.

What calcium does for your body

So why do you need calcium? Let’s run down the list of reasons why it’s so important.

Stronger bones

Bone is a mineralized connective tissue that gives your body structure — and calcium is a major component in every piece of your skeleton. (In case you were wondering, by the way, most adults have 206 bones in their body.)

Calcium hardens and strengthens your bones to give your body a solid framework. The mineral plays a key role in the growth and development of your bones when you’re young. As you age, calcium can help minimize your natural loss of bone density.

If you’re not getting enough calcium, your bones may weaken and become more vulnerable to breaks. (More on that in a moment.)

Blood clotting

Your blood needs to be able to clot (or stick together) so that you don’t bleed too much when you’re injured. Calcium helps activate platelets that form clots to stop the bleeding when you get a scrape or cut.

Nerve function

Calcium works to make sure your nerves can send messages throughout your body. It’s responsible for triggering the release of chemicals called neurotransmitters, which are the little messengers that keep your nerves in communication with one another.

Muscle contraction

There are more than 600 muscles in your body. As you can imagine, there’s an immense amount of work happening behind (err, inside) the scenes to keep them all synched up and moving properly.

“Calcium plays a key role in the complex scientific process that makes sure your muscles can interact with one another and generate the right amount of force you need for various movements,” explains Czerwony.

Teeth and gum health

Your pearly whites need calcium to develop and stay strong. One study found that calcium supplements in people over 65 helped reduce the risk of losing teeth with age. A lack of calcium also can lead to tooth decay and gum disease.

Blood pressure control

Having adequate stores of calcium has been shown to help regulate blood pressure, specifically during pregnancy. “This can help prevent pregnancy-related complications like hypertension and preeclampsia.”

Reduced cancer risk

Studies show that getting enough calcium may help protect you from colorectal cancer, though researchers aren’t yet sure exactly how. It may also be associated with a lower risk of other cancers.

But don’t go taking calcium supplements with the hopes of reducing cancer risk. The National Cancer Institute says there’s not enough evidence that supplements actually do that — so it’s still best to get your calcium through food.

What happens if you don’t get enough calcium?

Low levels of calcium in your blood (hypocalcemia) can lead to issues as your body steals calcium from your bones to compensate. “It causes the body to leach calcium from your bones to keep blood levels normal,” explains Czerwony.

This reduction in bone mineral density can eventually weaken your bones (osteopenia) and increase your risk for osteoporosis, leaving you with fragile, porous bones at a higher risk for breaks.

Low calcium can be caused by:

• Consuming excessive amounts of magnesium or sodium (salt)
• Drinking too much alcohol and/or caffeine
• Eating disorders
• Having your thyroid removed
• Long-term use of steroids or corticosteroids
• Vitamin D deficiency

Signs of a calcium deficiency could include fatigue, muscle pain and tingling in your hands and feet. The symptoms, however, may be so subtle that you may not even recognize them as a problem.

“It can be difficult to identify low calcium levels in your blood because you most likely won’t have symptoms until you’re experiencing a true deficiency,” says Czerwony.

Can you get too much calcium?

On the other end of the spectrum is hypercalcemia, or having too much calcium. It’s usually caused by primary hyperparathyroidism or certain cancers, but it can also happen if you take too many:

• Calcium supplements
• Vitamin A or D supplements
• Antacid tablets or chews (like Tums® or Rolaids®), which are made of calcium carbonate

“If your hypercalcemia is being caused by supplements and antacids, that usually reverses soon after you stop taking them,” says Czerwony.

Left unchecked, hypercalcemia can raise your risk of a heart attack and other health issues.

The NIH advises adults ages 19 to 50 to not exceed 2,500 mg of calcium in a day. For those aged 51 and older, the upper limit is 2,000 mg.

How to meet your calcium needs

There are lots of calcium-rich foods to help you meet your body’s needs. Many are probably sitting in your kitchen right now, too.

Dairy products in particular offer a healthy dose of calcium, says Czerwony. Just 8 ounces of low-fat vanilla yogurt has 388 mg of calcium, while the same amount of plain, low-fat Greek yogurt has 261 mg.

Can’t do dairy? No worries! Non-dairy foods like almond milk, fortified orange juice, spinach and black beans are all good sources of calcium, too. Tofu also is particularly high in calcium if you buy the kind prepared with calcium sulfate.

Eating foods high in vitamin D can help your body better absorb calcium, too.

Still, you might have trouble getting enough calcium in your diet if you don’t eat dairy.

“If you’re lactose intolerant, dislike dairy or follow a vegan diet, it can be difficult for you to get the right amount of calcium,” suggests Czerwony. “In these cases, supplements may be your best option.”

There are two main types of calcium supplements:

• Calcium carbonate, which is absorbed best with food and often found in over-the-counter antacids
• Calcium citrate, which can be taken with or without food

It’s best to talk with your healthcare provider before beginning calcium supplementation to determine how much calcium you might need, advises Czerwony.

It’s also important to know that your body can only absorb about 500 milligrams of calcium at a time, says Czerwony. Factor that in when planning out your meals or deciding when to take a supplement.

“Try to break up your calcium intake throughout the day,” says Czerwony. “Don’t take a calcium supplement right after your daily multivitamin, and don’t try to cram all of your calcium-rich foods into a single meal.”