Magnesium: The Nutrient at least 30% of Adults Are Short On And Nobody Talks About

Before my heart attack, if you’d asked me about magnesium, I’d have said something vague about muscle cramps. Maybe mentioned bananas, which I’m pretty sure isn’t even right. I genuinely could not have told you why it mattered, or what it actually did in the body, or why someone managing cardiovascular health should care about it at all.

I was pretty uninformed. Which, as it turns out, put me in good company.

But guess what? Magnesium is involved in more than 300 enzymatic reactions throughout the body. 300!  Not a minor player. And in the cardiovascular health arena, magnesium helps regulate cardiac rhythm, supports healthy blood vessels, and plays a central role in how your cells produce energy. That’s what we know of. It probably does a lot more.

And get this: According to an article published in Open Heart in 2018 titled: “Subclinical magnesium deficiency: A principal driver of cardiovascular disease and a public health crisis” (A public health crisis!) somewhere around 30% of adults are deficient in it, a number which varies and actually gets worse when looking across different disease populations, age, or medication status etc.

Bottom line, we can all afford to keep an eye on our magnesium intake. But how?

Part of the problem is that modern diets contain less magnesium than they used to, and absorption tends to decline as we age. Some researchers think the real figure is even higher, because standard blood tests measure magnesium in serum, which your body tightly regulates. It can look perfectly normal on a routine panel even when your cellular stores are running low.

So you can do your bloodwork, get a clean result, and still be running short on magnesium. Not ideal. And the list of early magnesium deficiency signs (muscle aches, poor sleep, constipation, brain fog, fatigue) can look like a whole lot of other things too. One thing that is certain is the human body is complex, and according to some estimates we probably only know about 80% of what magnesium does in our bodies.

What Magnesium actually does for our hearts (that we know of)

The one that really got me when I started digging into this was the cardiac rhythm research. A meta-analysis of randomized trials in patients recovering from acute coronary syndrome (heart attack) found that magnesium supplementation significantly reduced arrhythmias compared with placebo, cutting the risk by roughly two-thirds in some analyses. These are people already at serious cardiovascular risk, and the absolute differences in arrhythmia rates were clinically meaningful. It cut the risk by two-thirds. That’s worth taking seriously.

Blood pressure is the other big one, and honestly where most people in this community are probably focused day to day. A 2016 study pooled 34 randomized trials with over 2,000 participants and found meaningful reductions in both systolic and diastolic blood pressure versus placebo, with the biggest effect in people who already had high blood pressure or were running low on magnesium.

Then in 2024, a much larger umbrella analysis pooled 10 separate systematic reviews covering more than 8,600 people and found the same thing. Different researchers, different populations, same signal. Nearly a decade apart.

That kind of consistency is hard to ignore. But again, like everything, magnesium doesn’t work in isolation.

Why the form matters

Magnesium oxide is what shows up in most cheap supplements. Your body doesn’t absorb it particularly well, and it tends to cause GI discomfort. Magnesium glycinate, or bisglycinate, binds the magnesium to the amino acid glycine, which improves absorption significantly and is much gentler on digestion. It costs more to produce, which is why most generic formulas skip it.

The question is whether what you’re taking is trying to actually raise your magnesium levels. And most of us need this to be the case.

Age makes all of this more relevant, not less. Magnesium absorption naturally declines as you get older. Certain medications compound that. By the time you’re in your 40s and 50s, the odds of being below optimal are higher than most people realize, even if you think you’re eating reasonably well.

One thing worth asking your doctor about

Magnesium wasn’t even on my radar after my heart attack. Looking back, it probably should have been.

If you want a more accurate read on your magnesium status, it’s worth asking about a “Red Blood Cell” (RBC) Magnesium Test rather than relying solely on standard serum magnesium. Some clinicians prefer it because it may provide additional insight into longer-term magnesium status, though it’s not universally ordered. Most labs can run it. Worth asking.

If it were me, I’d also ask about hsCRP at the same time. Not directly related to magnesium specifically, but if you’re trying to understand what’s actually going on inside your cardiovascular system beyond cholesterol, that marker gives you another piece of the puzzle. Low-grade inflammation is a separate risk factor from LDL, and it’s one most people have no visibility into. I have a separate post on Inflammation worth reading.

I’m not suggesting everyone needs to supplement magnesium. Or that it’s a cure all. What I am saying is that it’s worth understanding, worth measuring properly, and worth having a real conversation about, rather than assuming everything’s fine because nothing showed up on a standard panel. And as evidence has consistently shown, most of us are deficient in it. That means at least 300 enzymatic processes in your body are laboring with not enough raw material to get their job done.

Because you only get one heart. ‘Til next time, Stephen.

Sources

Zhang, X., et al. (2016). Effects of magnesium supplementation on blood pressure: A meta-analysis of randomized double-blind placebo-controlled trials. Hypertension, 68(2), 324–333. PMID: 27402922.

Alharran, A. M., Alzayed, M. M., Jamilian, P., et al. (2024). Impact of magnesium supplementation on blood pressure: An umbrella meta-analysis of randomized controlled trials. Current Therapeutic Research, 101, 100755. PMID: 39280209.

Salaminia, S., et al. (2018). Evaluating the effect of magnesium supplementation and cardiac arrhythmias after acute coronary syndrome: A systematic review and meta-analysis. BMC Cardiovascular Disorders, 18(1), 129. PMID: 29954320.

DiNicolantonio, J. J., O’Keefe, J. H., & Wilson, W. (2018). Subclinical magnesium deficiency: A principal driver of cardiovascular disease and a public health crisis. Open Heart, 5(1), e000668. PMID: 29387426.