Bone health

Key minerals for bone health — magnesium

by Dr. Susan E. Brown, PhD

Overall, magnesium assures the strength and firmness of bones and makes teeth harder. Since magnesium participates in an astonishing array of biochemical reactions, it’s no surprise that it’s essential for healthy bones and teeth. Most notably, adequate magnesium is essential for absorption and metabolism of calcium. It also has a role to play, together with the thyroid and parathyroid glands, in supporting bone health: stimulating the thyroid’s production of calcitonin, which acts as a bone-preserving hormone, and regulating parathyroid hormone, which acts as a bone breakdown force.

Magnesium is an essential cofactor in 80% of all cellular enzymes. It is necessary for the conversion of vitamin D into its active form, and a deficiency of magnesium can lead to a syndrome known as vitamin D resistance. The enzyme required for forming new calcium crystals, alkaline phosphatase, also requires magnesium for activation, and if levels are low, abnormal bone crystal formation can result. Even mild magnesium deficiency is reported to be a leading risk factor for osteoporosis.

As with calcium, the majority of the body’s reserves of magnesium are held in the bone (60%), and the bones act as a storage reservoir, transferring magnesium to the blood in times of need. Adequate daily intake of magnesium is important throughout life to keep magnesium stored in the bones from being lost. Low magnesium intake, as well as low blood and bone magnesium levels, has been widely associated with osteoporosis in women.

It’s often overlooked that magnesium and calcium function together, so deficiency of one markedly affects the metabolism of the other. In fact, increasing calcium supplementation without increasing magnesium supplementation can actually increase magnesium loss. Similarly, the use of calcium supplements in the face of a magnesium deficiency can lead to calcium deposition in the soft tissues, such as the joints, where it can promote arthritis, or in the kidney, contributing to kidney stones.

There has been conflicting opinion about the need for concern about the adequacy of our magnesium intake. Despite its recognized importance, most Americans consume less than the Estimated Average Requirement (EAR) for magnesium. In fact, as of 2001, 56% of the US population was not consuming the Estimated Average Requirement for this mineral.

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Original Publication Date: 01/01/2009
Last Modified: 02/16/2010
Principal Author: Dr. Susan E. Brown, PhD