Nutrition & 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.
Magnesium 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, a function of which
is to regulate bone breakdown in a number of ways.
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 that is 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
into the blood stream in times of need. Adequate daily intake of magnesium is important throughout
life to keep the magnesium that is 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 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: 04/11/2000
Last Modified: 07/11/2014
Principal Author: Dr. Susan E. Brown, PhD