Understanding Magnesium - Its role in metabolism - Avoiding deficiency and excess

18 March 2008

Magnesium is an important mineral and electrolyte. It is a major constituent of bones and teeth. It is required by many body processes as an activator of enzymes. Although figures are quoted for minimum requirements, these are imprecise but generally accepted as being in region of 0.06% of diet (2.5% of b/wt) or 13 mg/kg. 0.5% is considered the maximum requirement. Prolonged supplementation with magnesium salts can lead, for instance, to phosphorous deficiency and lameness. (Black’s Veterinary Dictionary 7th ed 1964). Catastrophic long bone fractures may be a final outcome. For the performance horse, excess magnesium interfering with calcium may lead to metabolic disturbances such as heart malfunction and synchronous diaphragmatic flutters. (L.Benwell,unpublished, pers comm. 2007)