More than 99% of your calcium is stored in your bones and teeth, where it supports their function and structure. The rest of the calcium in your body is used for other critical functions, such as muscle contractions, nerve transmissions, blood vessel integrity, and blood circulation. Calcium also plays a central role in the activation of cells in the immune system.
Calcium is vital for maintaining your physical health, yet 3.5 billion people worldwide are estimated to be at risk for calcium deficiency due to inadequate dietary supply. In the United States alone, a National Health and Nutrition Examination Survey found that 44% of Americans had inadequate calcium intake.
Phytic acid is also shown to inhibit the absorption of calcium. Similar to zinc and iron, the more phytic acid you eat, the more calcium uptake is inhibited. Phytic acid consumption has not been linked to calcium deficiency in particular, but it will most likely contribute to impaired calcium absorption in a calcium-poor diet.
Severe calcium deficiency in children can cause growth and development delays. Whereas, the effects tend to be much more long-term in adults. This is because your body can use all the calcium stored in your bones and teeth before you start experiencing any problems.
Early signs of a chronic calcium deficiency may include minor symptoms like muscle cramps, weak fingernails, or lethargy. But over time, chronic calcium deficiency can lead to osteopenia, which, if left untreated, can lead to osteoporosis. The resulting loss of bone mass increases the risk of fractures, which may be the first visible sign of bone disease in many people with calcium deficiency.
Inadequate calcium intake has also been linked to an increased risk of obesity, high blood pressure, cardiovascular disease, and certain cancers.