Calcium Requirements and Dietary Sources


Verywell / Alexandra Shytsman

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Calcium is the most abundant mineral in the human body. The majority is stored in our bones and teeth (about 99%). The remaining 1% is found in our blood, muscles, and extracellular fluid.

Calcium is necessary for more than just healthy bones. It also plays a significant role in blood clotting, muscle contraction, hormonal secretion, and normal nervous system function. We get calcium from dairy products, green vegetables, fortified foods, and dietary supplements. Here's a closer look at how much calcium we need and what happens if we don't enough.

How Much Calcium Do I Need?

Dietary calcium recommendations vary slightly by age and sex. Certain health conditions make it more difficult to absorb calcium. Furthermore, various lifestyle and eating habits can cause a greater excretion of calcium (for instance, the amount of protein, sodium, phosphorus, and caffeine we consume).

The Recommended Dietary Allowance (RDA) offers a general guideline of how much daily calcium we should aim for to cover our basic needs:

  • Ages 1 to 3: 700mg
  • Ages 4 to 8: 1,000mg
  • Ages 9 to 18: 1,300mg
  • Ages 19 to 50: 1,000mg
  • Men ages 51 to 70: 1,000mg
  • Women ages 51 to 70: 1,200mg
  • All adults ages 71 and older: 1,200mg

The Adequate Intake of calcium for babies up to 6 months old is 200mg and for 7 to 12 months, 260mg.

Sources of Dietary Calcium

Dairy products are naturally high in calcium, but it's also available in certain plant foods and fortified products. If you don't eat cheese and yogurt, or drink cow's milk, be sure to include plenty of kale, chia seeds, and broccoli in your meal plan. Another natural source of calcium is the small bones in fish. Canned sockeye salmon or whole sardines contain soft bones that are chewable and rich in calcium.

Milk substitutes, including rice milk, almond milk, and soymilk are often fortified with calcium, but check the food label to be sure. Fortified tofu, cereals, and orange juice are additional ways to get non-dairy calcium.

Taking Calcium Supplements

Calcium supplements are often recommended for post-menopausal women to prevent osteoporosis. These are generally safe but should be shared with your doctor to ensure they won't interfere with any medications or impact other health conditions you may have.

Calcium supplements can be found in two forms: calcium citrate or calcium carbonate. If you've ever taken over-the-counter antacids, you're familiar with the chalky taste of calcium carbonate. While either form can contribute to your total calcium intake, calcium citrate is more easily absorbed. Calcium supplements are often combined with vitamin D to enhance absorption.

Calcium Deficiency Signs and Symptoms

You may be at risk for a calcium deficiency if you avoid dairy products, have a history of an eating disorder or multiple pregnancies, or suffer from malabsorptive conditions, like irritable bowel syndrome. Long-term use of certain medications, such as proton pump inhibitors, can also lead to a calcium deficiency.

Symptoms of low blood calcium (hypocalcemia) may include muscle cramps, lethargy, numbness, and tingling in the fingers, and problems with heart rhythm. However, because blood calcium levels are highly regulated, hypocalcemia is more often the result of an underlying medical condition or medication side effect, rather than a poor intake of dietary calcium.

You're unlikely to notice the symptoms of long-term calcium deficiency in everyday life, but fractured bones or a low score on a bone density test can cue you into an issue. Over time, calcium deficiency can lead to osteopenia, which is a loss of bone density. Osteopenia may progress into osteoporosis, where bones become weak and brittle.

Strengthening your muscles with weight-bearing exercise can improve bone density and reduce your risk of fractures. Certain medications also may be prescribed to improve bone density. Getting enough calcium, vitamin D, and physical activity (especially as a teenager and young adult) are some of the best ways to prevent issues with bone density later in life.

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  2. National Osteoporosis Foundation. Bone density exam/testing.

  3. National Osteoporosis Foundation. Weight bearing.

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