Magnesium: a mineral you need and may lack

The only time I ever thought about magnesium,  before I became a scientist, was the summer I swept magnesium shavings off the floor at the Kaiser helicopter-engine factory. When I went to college, I learned that magnesium was an essential mineral in human and animal bodies. As a veterinary medical student, I learned that a magnesium deficiency caused "grass tetany" in cattle that ate lush, heavily fertilized grass growing especially in soils high in potassium or aluminum; these conditions reduce availability of magnesium.

Recently, a MIT scientist, Inna Slutsky reported a five year study showing that magnesium improved learning abilities, working memory and both short- and long-term memory in rats. The improvements were produced in both young and old rats. They fed rats a synthetic magnesium supplement, magnesium-L-threonate (MgT), which improved the ability of magnesium to get across the blood-brain barrier and into nerve cells.

How magnesium benefits brain function is probably related to the fact that magnesium is a cofactor for enzymes that convert adenosine triphosphate (ATP) to adenosine pyrophosphoric acid (ADP), with the subsequent release of energy. The brain is a real energy hog.

How much MgT would humans need to take is not known, but presumably somebody is working on that. The recommended daily amount of magnesium is 400 milligrams for men and 310 milligrams for women. It is estimated that only 32% of Americans get this amount in their diet. Primary food sources are green veggies, fruits, and certain nuts.  Traditional nutritional supplements are not a solution. The researchers found that the magnesium in common dietary supplements does not readily enter the brain.

A commercial product, when it becomes available, may not have been tested for safety (nutritional supplements are not government regulated), On the other hand, healthy kidneys are pretty good at getting rid of excess blood magnesium. The possibility of excess magnesium in the brain from use of MgT has not been investigated.

Source:
Slutsky, I. et al. 2009. Enhancement of learning and  memory by elevating brain magnesium. Neuron. 65 (2): 165-177.

Copyright, 2010, W.  R. Klemm