What is calcium?

Calcium is a mineral that is important for bone health and plays a role in many other body systems.


Calcium is a grayish-white mineral found in nature in varying forms, often in forms referred to as salts. Calcium is an essential nutrient for every cell in the human body, although the largest quantities are found in the bones and teeth. The most common forms of dietary calcium (from food or supplements) are calcium carbonate and calcium citrate, although other forms, such as calcium malate and calcium hydroxyapatite (bone meal), are also used in supplements.

What are the dietary sources of calcium?

Dairy products, including milk, yogurt and cheese, are the richest sources of dietary calcium. Vegetable sources such as bok choy, kale, turnip greens and broccoli contain calcium. Fortified juices and cereals can increase dietary calcium intake. Although spinach contains a large quantity of calcium, it is not easily absorbed because it binds to a compound in spinach called oxalic acid, which prevents its absorption.

Should I consider taking a calcium supplement?

Research suggests that, for a large proportion of the population, diet alone does not supply adequate calcium. Taking a calcium supplement can help ensure that your cells and bones get the calcium they need.

You might not be getting enough calcium from your diet if you are lactose intolerant, have a milk allergy, have been taking certain medications or follow a dairy-free, vegan diet. A number of diseases also can cause you to need more (or less) calcium than normal.

In addition to getting enough calcium, you can take steps to help your body absorb and store calcium more efficiently. These steps include taking a vitamin D supplement and engaging in regular, weight-bearing exercise.

How can calcium affect my health?

Many people are aware that calcium helps build healthy bones and teeth, but did you know that it plays an important role in many other body systems as well? Calcium intake can support your health in several ways:

  • Helps achieve and maintain healthy bone mass*
  • Reduces the risk of osteoporosis later in life*
  • Supports strong teeth*
  • Helps maintain healthy blood pressure*
  • Promotes healthy mucus membranes in the colon*
  • Contributes to normal muscle contraction in skeletal muscle, the heart and blood vessels*
  • Provides support for women with PMS*
  • When taken with magnesium, it helps lower the risk of metabolic syndrome in women*
  • Transmits signals within and between cells, including nerve impulses to the heart*

Calcium is one of the most important nutrients for bone health.* It can help maximize the amount of bone mass you develop, which peaks at about age 30. In turn, this helps offset the loss of bone mass that occurs with aging, especially the rapid loss typically associated with menopause. If you lose too much bone, you can develop osteoporosis, a disease that causes bones to become weak, brittle and prone to fracture. Although osteoporosis is often thought of as a women's health issue, men also lose bone mass as they age and can get osteoporosis.

Although the chance of developing osteoporosis increases as a person ages, the condition can also affect younger people. Athletes can develop osteoporosis at any age, particularly when they don't consume enough nutrients and calories to meet the demands of their training and competition routines. This is especially prevalent in female athletes, who are at risk of a cluster of related conditions called the female athlete triad — the lack of adequate calories and nutrition (often due to eating disorders), menstrual irregularities (such as missing periods or not having periods), and weak bones. Increasing calcium intake as part of restoring a healthy diet and exercise program could help with recovery and help to restore lost bone mass.*

Dec. 09, 2016