How Does Calcium Enter Body?

Calcium is a mineral that occurs naturally in plants and soil. Mammals, including humans, store calcium in their bones and teeth, and excrete calcium through their milk and urine. Your body relies on calcium to strengthen bones, conduct electricity in nerves and for muscle contractions. Humans are not able to make calcium on their own; the only way calcium can enter the body is through diet or supplementation. When you consume calcium, your body uses vitamin D to absorb the majority of the calcium into your bones. The remainder of the calcium remains in your bloodstream for your body to use for vital functions.

Dietary Sources

Dietary sources of calcium include green vegetables such as broccoli, kale and cooked spinach. Ironically, spinach can also hinder your ability to absorb calcium. Vitamin C helps your body absorb the calcium in spinach, so you need to combine it with foods containing vitamin C, such as lemon juice, strawberries or oranges. Dairy products such as yogurt, cheese and milk all contain dietary calcium, as do canned, bone-in salmon and sardines. In addition to leafy greens, vegetarians can also get calcium from nuts and seeds, dried beans and blackstrap molasses. Manufacturers also fortify processed foods with calcium, including orange juice, cereals and soy products.

Supplementation

You can find calcium supplements in drugstores, vitamin stores and in the supplement section of some grocery stores. The Office of Dietary Supplements recommends that individuals over age 18 take 1,000 mg of calcium per day. Adults over age 51 should take between 1,000 and 1,200 mg. Calcium supplements are available in pill, liquid and chewable forms. You can find stand-alone calcium supplements, or varieties blended with vitamin D, which helps your bones absorb the calcium.

Calcium Deficiency

Certain groups, such as individuals with dairy allergies, vegans and strict vegetarians, are at greater risk for calcium deficiency. Calcium deficiencies do not produce immediate symptoms. Over time, if your dietary calcium intake remains inadequate, your bones will become weaker, causing a condition called osteoporosis, or osteopenia. Prolonged calcium deficiency, such as from an eating disorder, can adversely affect the neurological system and prevent proper muscle contractions. Individuals with severe deficiencies can experience numbness and tingling in the fingers, poor appetite, lethargy and convulsions, as well as abnormal heart rhythms and even heart attacks.

Too Much Calcium

It is almost impossible to consume too much dietary calcium, but it is possible to do so through supplementation. Individuals who consume too much calcium for prolonged periods might develop kidney stones. While certain recommended daily amounts have been determined, calcium also has a tolerable upper intake level. The tolerable upper intake level is the most calcium you can take, per day, without adverse effects. For adults over age 18, the tolerable upper intake level is 3,000 mg. Individuals over age 51 should take no more than 2,000 mg.