In the study, published Jan. 28 in Neuron, neuroscientists from the Massachusetts Institute of Technology (MIT) and Tsinghua University in Beijing found that increasing brain magnesium using a newly developed compound, magnesium-L-threonate (MgT), improves learning abilities, working memory, and short- and-long-term memory in rats. The magnesium also helped older rats perform better on a battery of learning tests.
"This study not only highlights the importance of a diet with sufficient daily magnesium, but also suggests the usefulness of magnesium-based treatments for aging-associated memory decline," one of the study's authors, Susumu Tonegawa, says in a news release. Tonegawa works at MIT's Picower Institute for Learning and Memory.
Although the experiments were conducted in rats, the results have implications for humans, the researchers say.
Half of the population of the industrialized world has a magnesium deficiency, researcher Guosong Liu says in the release. "If MgT is shown to be safe and effective in humans, these results may have a significant impact on public health." Liu is co-founder of Magceutics, a California-based company that develops drugs for the prevention and treatment of age-related memory decline and Alzheimer's disease.
MIT researchers developed MgT after discovering in 2004 that magnesium might enhance learning and memory. The MIT researchers examined how MgT stimulates changes in synapses, the junctions between neurons that are important in transmitting nerve signals.
The MIT researchers found that in young and old rats, MgT increased plasticity, or strength, among synapses and promoted the density of synapses in the hippocampus, a part of the brain that plays important roles in spatial navigation and long-term memory.
Other experiments performed within the study found that MgT treatment boosted memory recall under partial information conditions in older rats but had no effect in young rats. Aging causes dramatic declines in the ability to recollect memories when incomplete information is provided, the authors write.
"Because [magnesium] is an essential ion for normal cellular functions and body health, many physiological functions are impaired with the reduction of body [magnesium]," the MIT researchers write. The MIT researchers cite that only 32% of Americans get the recommended daily allowance of magnesium.
The recommended dietary allowance for magnesium for adults 19-30 years old is 400 milligrams/day for men and 310 milligrams/day for non-pregnant women. For adults 31 and older, it is 420 milligrams/day for men and 320 milligrams/day for non-pregnant women.
The researchers conclude that the study provides "evidence for a possible causal relationship between high [magnesium] intake and memory enhancements in aged rats." They also call for further studies to investigate the relationship between dietary magnesium intake, body and brain magnesium levels, and cognitive skills.
Slutsky, I. Neuron, Jan. 28, 2010; vol 65: pp 1-13.
News release, Massachusetts Institute of Technology.
Office of Dietary Supplements, National Institutes of Health.