Magnesium, the Mighty Mineral

The importance of magnesium was ignored for many years, but appreciation has grown with our understanding of the vital functions it fulfills.

Like calcium and phosphorus in the skeleton, magnesium has an important structural role as a component of bone, cell membranes and chromosomes.

Minerals as cofactors are associated with enzyme systems, usually at their active centers. Magnesium performs this function for hundreds of different enzymes. It is required for the synthesis of the major energy compound, ATP, and for its stable storage as MgATP. Magnesium is also essential for the production of protein, carbohydrates, lipids, DNA, RNA and the antioxidant glutathione.

Magnesium exists in the body in two forms - bound and ionized. Bound magnesium is incorporated into bone's structure or affixed to ATP, enzymes or blood proteins like albumin. The ionized form is magnesium in the blood or the tissues as a free magnesium ion, with two positive charges - Mg+2.

Ionized magnesium performs many important functions in the horse by competing with ionized calcium, which also has two positive charges - Ca+2.  Ionized Ca is an excitatory mineral for nerves that release the chemical [neurotransmittor] acetylcholine. When ionized Ca+2 enters the nerve it triggers release of acetylcholine which in turn activates other nerves or causes muscular contraction, both heart and skeletal muscle.  In addition, magnesium in the normal brain blocks access to a receptor called the NMDA receptor which is linked to hyperexcitability.

Magnesium also has important functions in the maintenance of both blood vessels and the lung's bronchi in a normal, open state. If all of this is not enough, research in people and experimental animals has linked normal magnesium status with helping to maintain glucose and insulin homeostasis.

Obviously optimal intake of magnesium is important. Guaranteeing your horse has correct magnesium levels is a little tricky. Blood (serum) levels are OK for seeing the extremes of high intake or severe depletion, but not very sensitive to levels in between which could still be interfering with normal function. Abnormally low levels can be present inside the cells or the fluid surrounding them when blood levels are normal.

A recent German study (Winter et al 2018) measured the magnesium level inside cells, specifically the lymphocyte white blood  cells, which is a much more sensitive test. This work started to establish a normal range for horses, but more work needs to be done before it is available as a commercial test.

The best test of the horse's status to date is called  fractional clearance of magnesium. This is determined by an equation after measuring concentrations of creatinine and magnesium in both blood and urine simultaneously. The tests are easy to run in any laboratory, but obtaining urine is time consuming or invasive and urine obtained after stimulating  urination with a diuretic cannot be used.

The best indicator of whether you horse should have supplemental magnesium is a diet analysis, including hay or pasture analysis. The National Research Council has established recommended minimum intakes for all ages and classes/uses. The horse may also benefit from having magnesium intake adjusted to a Ca:Mg ratio of 2:1.

Magnesium Oxide 58% is a highly concentrated source of Magnesium promotes healthy sugar metabolism, muscle  and heart function, and normal nervous system function.  Magnesium oxide has good bioavailability in horses.  It is the most concentrated magnesium source, meaning you can feed less than with other forms.

Magnesium Carbonate 25% is an essential dietary mineral that is often deficient in the horse's body.  It is essential for normal regulation of muscular and nervous system function, insulin sensitivity, energy storage and enzyme activity.  It is a low iron form of magnesium that is readily available to the horse, and also helps buffer high acid conditions in the stomach.

Bioplex Magnesium promotes healthy muscles and nervous system function. Involved in over 250 separate body reactions in the horse, magnesium also balances the actions of calcium, which has an excitatory effect on muscle and nervous system tissues.

Glycocemic EQ supports blood sugar levels within normal ranges.  Targeted ingredients also promote balanced immune and thyroid function, normal glucose metabolism, healthy nerve function, and proper insulin sensitivity.  Promotes healthy insulin levels by providing nutrient levels that are compatible with a wide variety of diets and sources of hay.  Available in a palatable powder or pellet.

Seroquine Paste, Powder or Pellet is a palatable herb-free calming supplement to support healthy nervous system function while maintaining alertness. May reduce hyperactivity and promote relaxation for normal emotional balance. With Magnesium to support a healthy stress response and nervous system function.  Also contains the B-vitamins Thiamine and Inositol, and Taurine, which helps modulate the stress hormones cortisol and adrenalin.