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.