Mice given extra doses of a new magnesium compound had better working memory, long-term memory and greater learning ability.

Before you go popping heavy doses of magnesium, however, know that much more testing is needed. Though rodent brains work similarly to ours, animal studies do not always predict what will happen in humans.

"If MgT is shown to be safe and effective in humans, these results may have a significant impact on public health," said Guosong Liu, director of the Center for Learning and Memory at Tsinghua University in Beijing, China.

Magnesium is an essential element found in some fruits, spinach, and other dark leafy greens. It is known to be important for the immune system. Consume less than 400 milligrams a day and you may be at greater risk for allergies, asthma and heart disease.

The element was shown brain-boosting abilities in earlier studies using cultured brain cells. But the new compound — magnesium-L-threonate (MgT) — was tested in animals and found to be effective.

"We found that elevation of brain magnesium led to significant enhancement of spatial and associative memory in both young and aged rats," Liu said.

In young and aged rats, MgT increased plasticity among synapses, the connections among neurons, and boosted the density of synapses in the hippocampus, a critical brain region for learning and memory.

"Half the population of the industrialized countries has a magnesium deficit, which increases with aging," Liu said. "If normal or even higher levels of magnesium can be maintained, we may be able to significantly slow age-related loss of cognitive function and perhaps prevent or treat diseases that affect cognitive function."

The research is detailed in the Jan. 28 issue of the journal Neuron. Funding was provided by the National Institutes of Health, the National Basic Research Program of China and other institutions.

Liu, a former MIT professor, is cofounder of Magceutics, a California-based company developing drugs for prevention and treatment of age-dependent memory decline and Alzheimer's disease.