Why You Might Be Deficient in Magnesium but Not Know It

magnesium deficient

Magnesium deficiency is more common than you think. In fact, you can be deficient in this essential mineral without even knowing it. Research shows that almost half of all Americans don’t get enough magnesium in their diet. That’s concerning because magnesium plays a key role in more than 300 chemical reactions in the body, including those involved in brain, heart, and muscle health. In fact, magnesium is an essential co-factor muscle cells need to make ATP, the high-energy chemical compound that acts as a universal energy source.

As the authors of a study published in the journal Open Heart point out:

“Hypomagnesemia is a relatively common occurrence in clinical medicine. That it often goes unrecognized is due to the fact that magnesium levels are rarely evaluated since few clinicians are aware of the many clinical states in which deficiency or excess, of this ion, may occur”

We think of calcium as being the bone health mineral, but magnesium is essential for bone health too. In fact, low levels of magnesium make it harder for calcium to get into the bone. Magnesium also helps convert vitamin D into its active form. One study found that when post-menopausal women took a magnesium supplement for two years, their bone density increased by 1% to 8%. That’s not surprising since almost 60% of the magnesium in your body is in your bones.

If you’re deficient in magnesium, you can find out through a blood test, right? Although there is a blood test for magnesium, it typically won’t pick up mild magnesium deficiency. In fact, the blood test may show normal levels of magnesium even if you’re mildly deficient. That’s because most of the magnesium in your body is stored in your bones and other tissues. Only 1% circulates in the bloodstream. That 1% is all you’re measuring when you do a standard magnesium blood test.

When there’s a shortfall of magnesium in the blood, tissues, and bone release their magnesium stores to help raise the blood level. The tissues “donate” their magnesium to the blood and this makes the blood level normal at the expense of the tissues. So, tissues can be deficient in magnesium while a blood test shows adequate levels of this important mineral. A standard magnesium blood test only shows a low level if a person is severely deficient.

How do you know if you’re magnesium deficient? Are you likely to have symptoms? Most people who are mildly deficient in magnesium have no symptoms. It’s only when you’re very low in magnesium that symptoms occur. Some possible symptoms of magnesium deficient include weakness, tremors, constipation, twitches, muscle weakness, and Irregular heart rhythm. You could be deficient in magnesium and have no symptoms at all.


·        Risk Factors for Low Magnesium:

·        Eating a mainly processed food diet (processed foods are low in magnesium)

·        Eating a diet high in sugar (increases magnesium excretion through the urine)

·        Consuming excess alcohol

·        Being over the age of 60

·        Having diabetes

·        Chronic stress

·        Consuming large amounts of caffeine

·        Breastfeeding and pregnancy

·        Taking certain medications, like diuretics, that cause loss of magnesium in the urine.

·        Taking corticosteroids


How Do You Know if You’re Magnesium Deficient?

Since most people who are low in magnesium have no symptoms, you might wonder how to know if you’re not getting enough. The reality is most people can benefit from having more magnesium in their diet. If you’re looking for a laboratory test to detect magnesium deficiency, your best bet is a magnesium red blood cell test period This test measures how much magnesium is inside a red blood cell. It can detect milder degrees of magnesium deficiency than a standard blood test for magnesium. This is a test to discuss with your doctor, as not all health care professionals use this test or are aware of it.

How to Add More Magnesium to Your Diet

It’s safest to get more magnesium from dietary sources as taking magnesium supplements can cause side effects like diarrhea. What are your best options? These foods are high in magnesium:

·        Green, leafy vegetables

·        Nuts, particularly almonds and cashews

·        Avocado

·        Legumes

·        Whole grains

·        Fish

·        Seeds, particularly pumpkin seeds

As you can see, eating a whole food diet that includes vegetables, nuts, avocado, legumes, seeds, whole grains, and fish supplies considerable amounts of magnesium. As you can see, simply, eating a whole food diet will boost the amount of magnesium in your diet. However, processed foods don’t make the cut. For example, 85% of magnesium is lost when whole wheat flour is refined to make white flour. In addition, the magnesium content of fruits and vegetables has declined somewhat over the last 50 years.

However, it’s best not to add a magnesium supplement without consulting your physician first. Taking too much of one mineral in supplement form can impact levels of another. For example, taking calcium supplements can decrease tissue levels of magnesium. It makes sense since the two minerals compete with one another for absorption, so too much of one can reduce the absorption of the other.

Also, most of the evidence for magnesium’s health benefits come from consuming a magnesium-rich diet rather than supplements. Supplements don’t always behave the same in the human body as food sources do.

The Bottom Line

Now you know why you can be deficient in magnesium and not know it. The standard blood test for detecting magnesium deficiently only picks it up in cases of severe deficiency. With almost half of the population not getting enough magnesium, the odds are that you could use more in your diet are high and there’s little harm to eating more magnesium-rich foods as they tend to be healthy foods.

What about supplemental magnesium? There’s some evidence that magnesium supplements or consuming more dietary magnesium can help some health problems, most notably, anxiety, depression, and insomnia. Also, some studies suggest that magnesium may modestly improve insulin sensitivity and help with blood sugar control. Plus, diabetics tend to be low in magnesium. So, it’s especially important if you have diabetes or pre-diabetes that you get enough magnesium in your diet.  The take-home message? Eat unprocessed food, skip the sugar, and choose more foods that are high in magnesium.



·        University Health News. “Magnesium for Bone Health”

·        National Institutes of Health. “Magnesium”

·        Open Heart. 2018; 5(1): e000668.

·        Scientifica (Cairo). 2017; 2017: 4179326.

·        Medical News Today. “What to Know about Magnesium Deficiency”


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