Of all the minerals found in the body, calcium is the most abundant. The majority of the calcium present in the body is located in the bones and teeth. A small amount of this nutrient circulates in the blood stream and other areas in the body, such as the cells. Normal blood levels of calcium are required for essential body processes to occur and prevent health problems.
Benefits
Calcium is needed for bone and teeth formation and maintenance. It is also involved in secretion of hormones, such as insulin, and in blood clotting. This nutrient helps muscles contract and facilitates transmission of nerve impulses. Contraction and relaxation of blood vessels also require calcium to occur. The Medline Plus Medical encyclopedia explains that the human body needs calcium for growth, maintenance and reproduction.
Regulation
Calcium levels in the blood are regulated by parathyroid hormone. This hormone is secreted by the parathyroid glands located in the neck. When blood levels of calcium drop, the parathyroid glands release parathyroid hormone. Parathyroid hormone then stimulates the conversion of vitamin D to calcitriol in the kidneys. To increase blood levels of calcium, calcitriol stimulates absorption of this nutrient in the small intestines and in the kidneys. It also causes release of calcium from the bones to the bloodstream, which could lead to weak bones. When blood levels of calcium are normal, the parathyroid glands stop producing parathyroid hormone. The kidneys then dispose of excess calcium via urine.
High Blood Calcium Levels
Hypercalcemia is a term used to describe blood levels of calcium that are too high. It may occur when the parathyroid glands over produce parathyroid hormones or when a person consumes a lot of vitamin D. People who consume a lot of milk and calcium-containing antacids because they have peptic ulcers can also develop hypercalcemia. Sometimes, diseases in which bone is broken down can lead to hypercalcemia, according to Merck Manuals Online Medical Library.
Low Blood Calcium Levels
Abnormally low blood calcium levels are referred to as hypocalcemia. Problems with parathyroid hormone can cause hypocalcemia. When this hormone is too low, non existent or if the body does not respond to it properly, hypocalcemia can occur. Also, inadequate intake or excessive excretion of calcium can lead to hypocalcemia. The parathyroid glands need magnesium to work properly. So, low levels of magnesium could cause hypocalcemia as well as vitamin D deficiency. Because vitamin D is converted to calcitriol in the kidneys, kidney problems that prevent this from occurring can cause hypocalcemia as well.
Effects
Hypercalcemia causes symptoms like nausea and constipation. It can also cause extreme thirst because it induces production of large volumes of urine. An uncommon effect of hypercalcemia is kidney failure, while long term hypercalcemia often causes kidney stones that contain calcium.
Hypocalcemia causes tingling in areas like the tongue, fingers, lips and feet. It may also result in muscle spasms, stiffening and seizures. Both low and high levels of calcium in the blood can cause brain dysfunction and abnormal heart beats.
