Magnesium. I Can’t Believe I’m Going To Say This. Are You Getting Enough?

Dr. George Lundberg, the Editor-at-Large at Medscape and a former Editor-in-Chief of JAMA (Journal of the American Medical Association) is making me rethink a mineral I pushed aside as just one in a sea of essential nutrients that a good diet should provide. Lundberg thought that once too:1

For most of my professional life, I have supported the adequacy of a balanced diet and opposed the addition of nutritional supplements as unnecessary, wasteful, possibly harmful, and mostly a scam. But as the “typical” American diet has evolved into one of fast foods and processed foods, my attitude has changed.

First off, a deficiency or inadequacy is hard to detect:

Approximately 99% of total body magnesium is located in bone, muscles, and soft tissues; 1% is extracellular.[1] Thus, plasma or serum magnesium levels are only a rough approximation of amounts of magnesium. Substantial hypomagnesemia does indicate magnesium deficiency, but normal blood levels do not dependably exclude significant depletion of magnesium stores.

And we may not be eating very much:

In 2009, the World Health Organization published a report[2] that stated that 75% of Americans consumed less magnesium than needed.

So, you can’t effectively check status with a blood test, magnesium is really important (“involved in more than 300 regulatory enzyme systems”), and things like taking antacids or drinking even small amounts of alcohol deplete it. What to do? Eat more magnesium-rich foods:

MagnesiumFoodSources2

Source: National Institutes of Health: Magnesium Fact Sheet

Lundberg says he now emphasizes magnesium-rich foods, and because he drinks wine and takes an antacid, he supplements with 400 mg/day:

I feel terrific — better than before magnesium. I know that is subjective as all hell, but what better way would you like your patients to feel than “terrific”?

I’m a fan of the guy, so this post is subjective as all get out.

1Magnesium Deficiency: The Real Emperor of All Maladies?, Medscape, 11 May 2015

2 thoughts on “Magnesium. I Can’t Believe I’m Going To Say This. Are You Getting Enough?

  1. Darryl

    Please delete the other comment – my less than and greater than characters are interpreted as html tags, leading to a gibberish second paragraph.

    The best paper I’ve seen is Joosten MM et al 2013. Urinary and plasma magnesium and risk of ischemic heart disease, which followed 7664 people for a decade after two 24-h urine collections.

    Those with low magnesium intake had significantly higher hypertension and C-reactive protein (a measure of systemic inflammation), but there wasn’t much difference in overall mortality. Only those in the lowest quintile (M: less than 71 mg; F: less than 59 mg) had significantly increased heart disease incidence and mortality, but there was a borderline trend to higher risk in the highest quintile as well (M: greater than 133 mg; F: greater than 112 mg) as well, with a U-shaped hazard ratio figure. About 30% to 40% of dietary Mg is absorbed, so this points to higher risks from intakes less than 230 mg, and possibly from intakes greater than 440 mg. Given the standard dose of magnesium supplements are usually 400 mg, it seems likely one would readily fall into the top quintile with supplements.

    While there are numerous studies attesting to benefits of magnesium supplementation in managing cardiac arrythmias and hypertension, there are few trials looking at longer term outcomes. One Indian study found supplementing 200 high risk men to 1142 mg total intake reduced their total mortality by 40%, while a Danish double blind placebo controlled study found patients receiving 354 mg magnesium had 55% increased rate of cardiac events. The evidence is fairly equivocal.

    Personally, I do supplement, but only 140 mg daily from OTC magnesium salicylate tablets I’m taking primarily for the salicylate (as a less-hazardous alternative to aspirin).

    Reply

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