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Calcium Hydroxyapatite Review

Calcium hydroxyapatite sometimes called HA, calcium microcrystalline hydroxyappatite, calcium-hydroxyapatite | ArticleMCHA, ossein hydroxyapatite or MCHC, is found in the teeth and bones of humans and animals. It is composed of calcium (approx. 24%), phosphorus (10%), protein (22%), trace minerals and glycosaminoglycans found naturally in the bone matrix.  These supplements are commonly derived from calf bone.

Results of Calcium Hydroxyapatite Studies
Companies that sell calcium hydroxyapatite cite several studies to demonstrate its efficacy for bone health.  HA has prevented bone loss or increased bone density in conjunction with drugs in four studies (Epstein, 1982, Pines, 1984, Castelo Branco 1999, Pelayo 2008,). It also increased forearm bone density when taken with prescription drugs.  3000 milligrams of calcium hydroxyappatite daily increased bone density in the forearm in postmenopausal women (Fernandez-Parejo et al, 2007).

In a 9-month study entitled “Effect of a Dietary Supplement on Hip and Spine BMD: A Randomized, Double-blind, Placebo-controlled Trial," Tucker concluded that calcium hydroxyapatite:

“resulted in significantly greater BMD for three of the four measurements taken at the hip, including the total hip, femoral neck, and inter-trochanteric region, than placebo use after 9 months of daily use. Also, of the four BMD assessments at the hip, significant differences were evident in two after 6 months of supplement use. Apparently, the supplement is effective in improving BMD at the hip compared to placebo use in women, which should result in reduced risk of {bone loss]...”

HA did not increase bone density of the spine in that study. Because of the short duration of this trial, no longer term conclusions may be reached.

Misleading Findings for Calcium Hydroxyapatite
Not all researchers find the calcium hydroxyapatite research compelling. Because drugs were also used by patients, it is difficult to determine the effect of HA alone. Perhaps its most impressive result involved an increase in forearm bone mineral density (BMD).  While certainly beneficial, forearm BMD does not carry the medical importance of the hip or spine bone strength to patients.

In the journal Nutritional Clinical Practitioner (2007 (3):286-96). Straub authored “Calcium supplementation in clinical practice: a review of forms, doses, and indications.” He recommends against taking certain calcium forms, including calcium hydroxyapatite.

“Calcium from carbonate and citrate are the most common forms of calcium supplements. Calcium carbonate, the most cost-effective form, should be taken with a meal to ensure optimal absorption. Calcium citrate can be taken without food and is the supplement of choice for individuals with achlorhydria or who are taking histamine-2 blockers or protein-pump inhibitors. Calcium lactate and calcium gluconate are less concentrated forms of calcium and are not practical oral supplements. Research on hydroxyapatite as a source of calcium is limited, so this form of calcium is not recommended."

calcium-hydroxyapatite | ArticleCalcium hydroxyappatite appears to have certain bone benefits, but may need more research. Unlike calcium supplements such as AdvaCAL, it alone does not have the record of increasing bone density in multiple long term trials involving the critical bones such as the spine, HA is also quite insoluble.  As with calcium carbonate, one should also consume food while taking this supplement to ensure adequate absorption of calcium hydroxyapatite.