An Element of Protection

One of the most abundant elements in the universe and on earth, magnesium—which is literally stardust—is essential to the function of the human body (as well as those of all other animals, and plants, too). It’s vital to energy production, muscle and nerve function, protein synthesis, and enzyme activity. It stabilizes heart rate, helps regulate insulin metabolism, and relaxes blood vessels, among many other roles. Now, new technology is furnishing evidence that the mineral is far more widely active in the body than anyone suspected. Researchers in Italy recently discovered, for example, that thousands of the body’s proteins inherit the capacity to bind to magnesium and warrant being collectively distinguished as “the magnesome.” The mineral, many now believe, plays a significant role in human health, and accumulating evidence suggests that its most important job may be in protecting the brain. One of the big puzzles of contemporary science is Alzheimer’s disease, the chronic neurodegenerative disorder marked most prominently by short-term memory loss. Not only is the cause unclear, but there is no way to stop the progression of symptoms. Neuroscientists in the United States and China, however, are accumulating evidence that delivering magnesium ions to the brain may reverse cognitive deficits typical of the disorder by preventing loss of the connections between nerve cells. Using a form of magnesium, he adapted to penetrate the blood-brain barrier, Guosong Liu, formerly head of the Centre for Learning and Memory at MIT, now at Tsinghua University in Beijing, finds that the element restores synaptic function by increasing the density of synapses, especially in the hippocampus. In studies of both young and old animals, including those with amyloid deposits considered the hallmark of Alzheimer’s pathology, magnesium “rescues” the transmission of signals that underlie memory and learning. Placebo-controlled trials of magnesium in human subjects are now underway. Studies that track the development of disorders over time show that low levels of magnesium intake are also linked to depression. In a recent Finnish study of more than 2,300 middle-aged men followed for 20 years, those who were eventually diagnosed with depression had lower magnesium levels than those who never developed the disorder. Researchers suggest several ways that magnesium may be protective. The mineral helps regulate the hypothalamic-pituitary axis, the main stress-response system, controlling circulating levels of the stress hormone cortisol. In addition, magnesium acts as a cofactor for the synthesis of substances essential for the transmission of nerve impulses in the brain. It also appears to increase levels of BDNF, a protein that promotes learning and adaptability by stimulating the growth of new neurons. What’s more, depression is increasingly seen as a disorder involving or reflecting inflammatory processes in the brain, and magnesium deficiency is associated with increased levels of inflammation-promoting substances. Raising magnesium levels in the brain may also help to curb anxiety. Without a robust fear memory, humans would likely not have lived to tell their stories or develop science. But the very same capacity underlies our propensity to anxiety. Liu and colleagues find that magnesium enhances the extinction of fear memory—one of the goals of psychotherapy. And it does so without disrupting the ability to lay down fear memories in the first place. The human body doesn’t make magnesium; all we need must come from our diet. And while it’s present in many foods, fewer than a third of Americans get enough from their diet to meet their daily requirement. The mineral is stripped out of many foods when they undergo processing. Adolescent females and elderly men are most likely to have an insufficient intake of magnesium. Magnesium in Mind Enhances synaptic plasticity and density; Strengthens synaptic connections, boosting learning ability; Promotes short- and long-term memory; Counters depression; Spurs extinction of fear memory; Reverses cognitive deficits in Alzheimer’s disease; Increases duration of deep sleep; Decreases levels of stress hormone cortisol. Elemental Intelligence The average U.S. intake for magnesium is 250mg/day, while the Recommended Dietary Allowance for adults is 400–420 mg/day for males and 310–320 mg/day for females. Bones serve as the major reservoir of magnesium in the body, with muscle cells the runner-up. There is no simple test for measuring magnesium levels in the body because most magnesium is sequestered in bone and muscle cells. Magnesium is required for the synthesis of DNA and RNA. Because the magnesium content of soil has been declining for several decades, so has the magnesium content of produce. Processing and refining of grains further diminish the magnesium content of food. Studies show that magnesium intake declines with age. A Mineral’s Many Roles Regulates blood pressure; Regulates muscle contraction and relaxation; Prevents migraine headaches; Enables immune function; Contributes to bone structure; Low levels linked to risk of sudden cardiac death; Essential to glucose metabolism and insulin sensitivity.

Psychology Today, 7 May 2016 ; ;