Magnesium is a vital nutrient that is often deficient in modern diets. Our ancient ancestors would have had a ready supply from organ meats, seafood, mineral water, and even swimming in the ocean, but modern soils can be depleted of minerals and magnesium is removed from water during routine municipal treatment. The current RDA for adults is between 320 and 420mg daily, and the average US intake is around 250mg daily.
Does it matter if we are a little bit deficient? Well, magnesium plays an important role in biochemical reactions all over your body. It is involved in a lot of cell transport activities, in addition to helping cells make energy aerobically or anaerobically. Your bones are a major reservoir for magnesium, and magnesium is the counter-ion for calcium and potassium in muscle cells, including the heart. If your magnesium is too low, you can experience muscle cramps, arrythmias, and even sudden death. Ion regulation is everything with respect to how muscles contract and nerves send signals. In the brain, potassium and sodium balance each other. In the heart and other muscles, magnesium pulls some of the load.
That doesn't mean that magnesium is unimportant in the brain. Au contraire! In fact, there is an intriguing article entitled Rapid recovery from major depression using magnesium treatment, published in Medical Hypothesis in 2006. Medical Hypothesis seems like a great way to get rampant (but referenced) speculation into the PubMed database. Fortunately, I don't need to publish in Medical Hypothesis, as I can engage in such speculation in my blog, readily accessible to Google. Anyway, this article was written by George and Karen Eby, who seem to run a nutrition research facility out of an office warehouse in Austin, Texas - and it has a lot of interesting information about our essential mineral magnesium.
Magnesium is an old home remedy for all that ails you, including "anxiety, apathy, depression, headaches, insecurity, irritability, restlessness, talkativeness, and sulkiness." In 1968, Wacker and Parisi reported that magnesium deficiency could cause depression, behavioral disturbances, headaches, muscle cramps, seizures, ataxia, psychosis, and irritability - all reversible with magnesium repletion.
Stress is the bad guy here, in addition to our woeful magnesium deficient diets. As is the case with other minerals such as zinc, stress causes us to waste our magnesium like crazy - I'll explain a bit more about why we do that in a minute.
Let's look at Eby's case studies from his paper:
A 59 y/o "hypomanic-depressive male", with a long history of treatable mild depression, developed anxiety, suicidal thoughts, and insomnia after a year of extreme personal stress and bad diet ("fast food"). Lithium and a number of antidepressants did nothing for him. 300mg magnesium glycinate (and later taurinate) was given with every meal. His sleep was immediately restored, and his anxiety and depression were greatly reduced, though he sometimes needed to wake up in the middle of the night to take a magnesium pill to keep his "feeling of wellness." A 500mg calcium pill would cause depression within one hour, extinguished by the ingestion of 400mg magnesium.
A 23 year-old woman with a previous traumatic brain injury became depressed after extreme stress with work, a diet of fast food, "constant noise," and poor academic performance. After one week of magnesium treatment, she became free of depression, and her short term memory and IQ returned.
A 35 year-old woman with a history of post-partum depression was pregnant with her fourth child. She took 200mg magnesium glycinate with each meal. She did not develop any complications of pregnancy and did not have depression with her fourth child, who was "healthy, full weight, and quiet."
A 40 year-old "irritable, anxious, extremely talkative, moderately depressed" smoking, alchohol-drinking, cocaine using male took 125mg magnesium taurinate at each meal and bedtime, and found his symptoms were gone within a week, and his cravings for tobacco, cocaine, and alcohol disappeared. His "ravenous appetite was supressed, and ... beneficial weight loss ensued."
Eby has the same question about the history of depression that I do - why is depression increasing? His answer is magnesium deficiency. Prior to the development of widespread grain refining capability, whole grains were a decent source of magnesium (though phytic acid in grains will bind minerals such as magnesium, so the amount you eat in whole grains will generally be more than the amount you absorb). Average American intake in 1905 was 400mg daily, and only 1% of Americans had depression prior to the age of 75. In 1955, white bread (nearly devoid of magnesium) was the norm, and 6% of Americans had depression before the age of 24. In addition, eating too much calcium interferes with the absorption of magnesium, setting the stage for magnesium deficiency.
Beyond Eby's interesting set of case studies are a number of other studies linking the effects of this mineral to mental health and the stress response system. When you start to untangle the effects of magnesium in the nervous system, you touch upon nearly every single biological mechanism for depression. The epidemiological studies (1) and some controlled trials (2)(3) seem to confirm that most of us are at least moderately deficient in magnesium. The animal models are promising (4). If you have healthy kidneys, magnesium supplementation is safe and generally well-tolerated (up to a point)(5), and many of the formulations are quite inexpensive. Yet there is a woeful lack of well-designed, decent-sized randomized controlled trials for using magnesium supplementation as a treatment or even adjunctive treatment for various psychiatric disorders.
Let's look at the mechanisms first. Magnesium hangs out in the synapse between two neurons along with calcium and glutamate. If you recall, calcium and glutamate are excitatory, and in excess, toxic. They activate the NMDA receptor. Magnesium can sit on the NMDA receptor without activating it, like a guard at the gate. Therefore, if we are deficient in magnesium, there's no guard. Calcium and glutamate can activate the receptor like there is no tomorrow. In the long term, this damages the neurons, eventually leading to cell death. In the brain, that is not an easy situation to reverse or remedy.
And then there is the stress-diathesis model of depression, which is the generally accepted theory that chronic stress leads to excess cortisol, which eventually damages the hippocampus of the brain, leading to impaired negative feedback and thus ongoing stress and depression and neurotoxicity badness. Murck tells us that magnesium seems to act on many levels in the hormonal axis and regulation of the stress response. Magnesium can suppress the ability of the hippocampus to stimulate the ultimate release of stress hormone, it can reduce the release of ACTH (the hormone that tells your adrenal glands to get in gear and pump out that cortisol and adrenaline), and it can reduce the responsiveness of the adrenal glands to ACTH. In addition, magnesium can act at the blood brain barrier to prevent the entrance of stress hormones into the brain. All these reasons are why I call magnesium "the original chill pill."
If the above links aren't enough to pique your interest, depression is associated with systemic inflammation and a cell-mediated immune response. Turns out, so is magnesium deficiency. In addition, animal models show that sufficient magnesium seems to protect the brain from depression and anxiety after traumatic brain injury (6), and that the antidepressants desipramine and St. John's Wort (hypericum perforatum) seem to protect the mice from the toxic effects of magnesium deficiency and its relationship to anxious and depressed behaviors (4).
The overall levels of magnesium in the body are hard to measure. Most of our body's magnesium is stored in the bones, the rest in the cells, and a very small amount is roaming free in the blood. One would speculate that various mechanisms would allow us to recover some needed magnesium from the intracellular space or the bones if we had plenty on hand, which most of us probably don't. Serum levels may be nearly useless in telling us about our full-body magnesium availability, and studies of levels and depression, schizophrenia, PMS, and anxiety have been all over the place (7). There is some observational evidence that the Mg to Ca ratio may be a better clue. Secondly, the best sources of magnesium in the normal Western diet are whole grains (though again, phytates in grains will interfere with absorption), beans, leafy green veggies, and nuts. These happen to be some of the same sources as folate, and folate depletion is linked with depression, so it may be a confounding factor in the epidemiological studies.
Finally, magnesium is sequestered and wasted via the urine in times of stress. I'm speculating here, but in a hunter-gatherer immediate stress sort of situation, maybe we needed our neurons to fire on all cylinders and our stress hormones to rock and roll through the body in order for us to survive. Presumably we survived or didn't, and then the stressor was removed, and our paleolithic diets had plenty of magnesium to replace that which went missing. However, it may not be overall magnesium deficiency causing depression and exaggerated stress response - it may just be all that chronic stress, and magnesium deficiency is a biomarker for chronic stress. But it doesn't hurt to replete one's magnesium to face the modern world, and at least the relationships should be studied thoroughly. Depression is hugely expensive and debilitating. If we could alleviate some of that burden with enough mineral water... we should know whether that is a reasonable proposition.
As I mentioned before, there are only a few controlled trials of magnesium supplementation and psychiatric disorders. A couple covered premenstrual dysphoria, cravings, and other symptoms (8)(9). Another small study showed some improvement with magnesium supplementation in chronic fatigue syndrome (10). Two open-label studies showed some benefit in mania (11)(12). There is another paper that postulates that magnesium deficiency could exacerbate the symptoms of schizophrenia. However, there is nothing definitive. Which is, of course, quite troubling. How many billions of dollars have we spent on drug research for depression, bipolar disorder, and schizophrenia, when here is a cheap and plausibly helpful natural remedy that hasn't been properly studied?
So everyone get out there and take some magnesium already! Whew. Well, just a few more things to keep in mind before you jump in.
There are some safety considerations with respect to magnesium supplementation. If you have normal kidney function, you do not have myasthenia gravis, bowel obstruction, or bradycardia, you should be able to supplement without too many worries. In addition, magnesium interferes with the absorption of certain pharmaceuticals, including dixogin, nitrofurantoin, bisphosphanates, and some antimalaria drugs. Magnesium can reduce the efficacy of chloropromazine, oral anticoagnulants, and the quinolone and tetracycline classes of antibiotics.
Magnesium oxide is the cheapest readily available formulation, as well as magnesium citrate, which is more likely to cause diarrhea in excess. (In fact, magnesium is a great remedy for constipation). The oxide is not particularly bioavailable, but the studies I've referenced above suggest that you can top yourself off after about a month of daily supplementation. Those with short bowels (typically due to surgery that removes a large section of bowel) may want to supplement instead with magnesium oil. You can also put some Epsom salts in your bath. In addition to diarrhea, magnesium can cause sedation, and symptoms of magnesium toxicity (again, quite unlikely if your kidneys are in good shape) are low blood pressure, confusion, arrythmia, muscle weakness, and fatigue. Magnesium is taken up by the same transporter as calcium and zinc, so they can fight with each other for absorption. Jaminet and Jaminet recommend total daily levels (between food and supplements) of 400-800mg. Most people can safely supplement with 200-350mg daily without any problems (again, don't proceed without a doctor's supervision if you have known kidney disease or if you are elderly).
Image credit (magnesium is used to make sparklers)
More articles like this one at Evolutionary Psychiatry
Copyright Emily Deans, M.D.