Homeostasis is a key concept in biology. It describes the situation when the internal conditions of living organisms remain stable (within a normal range), regardless of what is going on in the external environment. These internal conditions include your body temperature, pH level, glucose level, and minerals in your body that carry out many different functions.

The body contains small amounts of a large number of different minerals and three of the most important are calcium (Ca), phosphorus (P, which exists as phosphate in the body) and magnesium (Mg). About 99% of the body’s calcium is stored in the bones, but other cells (particularly muscle cells) and blood also contain calcium. Calcium is essential for the formation of bone and teeth, muscle contraction, signaling between nerve cells, blood clotting, and the normal functioning of many enzymes. Bone also contains about 85% of the body’s phosphate. The rest is located primarily inside cells, where it is involved in energy production. Phosphate is also necessary for the formation of bone and teeth and it is used as a building block for several important substances, including those used by the cell for energy, cell membranes, and DNA. Magnesium is the fourth most abundant mineral in your body. It’s involved in over 600 cellular reactions, from making DNA to helping your muscles contract and modulating signaling between nerve cells.

Homeostasis of these minerals is achieved by the coordinated interaction among absorption from the intestine, the balance between reabsorption and excretion by the kidney, and storage in bone (for Ca and phosphate). Specific hormones in the body also contribute to the maintenance of mineral homeostasis. The most important of these are parathyroid hormone, activated vitamin D (also called calcitriol), fibroblast growth factor-23. Mineral homeostasis may change with age and altered requirements in conditions such as pregnancy and the actions of these hormones help meet the body’s changing demands.

While the mechanisms within the body can maintain mineral homeostasis over a wide range of internal conditions, it cannot overcome insufficient intake of these minerals over the long term. Thus, a good diet is essential for helping your body to maintain mineral homeostasis.

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