Should You Be Taking Magnesium Supplements?


By: Katie McCallum

Add magnesium to the list of supplements that have gained popularity over the last few years.

Magnesium supplements are nothing new, of course — a staple of the dietary supplement aisle for decades.

Lately, though, they have been touted for a number of wellness benefits, such as a sleep-aid alternative to melatonin and as a way to boost the immune system amidst the COVID-19 pandemic.

"Magnesium plays several important roles in your body, and we need to get enough of this mineral nutrient to live a healthy life," says Dr. Noorhan Nassar, a primary care doctor at Houston Methodist.

The question, though, is whether getting enough magnesium really requires taking a supplement?

What does magnesium do for the body?

"Magnesium regulates the function of hundreds of enzymes, acts as an important electrolyte and helps your body build proteins," explains Dr. Nassar. "It also works closely with another essential mineral, calcium."

Through these actions, magnesium helps manage many essential processes in your body, including supporting:

  • Muscle function
  • Nerve conduction and signaling
  • Energy production
  • Normal heart rhythm
  • Bone health

"It also helps broadly regulate blood sugar levels and blood pressure," Dr. Nassar adds.

Given the numerous roles it plays, it's important to be sure your body has all the magnesium it needs to function optimally.

How common is low magnesium?

Dr. Nassar notes that most adults don't need to be too worried about their magnesium levels.

"For the average person who maintains a well-balanced diet, it's rare to be deficient in magnesium," Dr. Nassar says.

That's because it's naturally found in many foods. Other food items, like some breakfast cereals, are fortified with it.

And even if a person's magnesium intake is low from time to time, healthy kidneys are very good at making sure your body retains the amount of magnesium you need. They also get rid of excess magnesium you don't need.

Some people, however, do suffer from low magnesium. And if a person's levels remain low for long periods of time, they're considered magnesium deficient.

However, Dr. Nassar notes that deficiency is rarely the result of getting too little magnesium in your diet.

Instead, magnesium deficiency is typically caused by conditions that adversely affect the gastrointestinal tract's absorption of magnesium, such as chronic diarrhea; or the kidneys' retention of it, such as uncontrolled diabetes.

Should healthy people take magnesium supplements?

The claimed benefits of magnesium supplementation range from boosts in everyday wellness — better sleep, increased energy levels and improved mood — to specific health benefits, such as lower blood pressure, reduced risk of heart disease and improvement in migraines.

Whether these claims are true or not ... that's where things get murky.

Take, for instance, lower blood sugar.

While studies show that people with low magnesium tend to have higher blood pressure, Dr. Nassar adds that many other factors that affect blood pressure aren't controlled for in these studies. Even with that caveat aside, there's not enough data to say that magnesium supplementation actually helps lower blood pressure anyway.

"Other studies looking at the benefits of magnesium for healthy people often don't check the participants' magnesium levels prior to starting the study," Dr. Nassar adds.

Without this benchmark, it's hard to know whether the improvements seen are actually due to supplementation. Remember, healthy kidneys naturally retain the magnesium you need and excrete any excess.

"From an anecdotal standpoint, people will certainly tell you that magnesium supplements work," says Dr. Nassar. "But the actual data supporting benefits of supplementation in otherwise healthy adults isn't complete — results are mixed and the design of these studies isn't always ideal."

In other words, there's no clear proof that magnesium supplements provide any benefit to healthy adults who aren't deficient.

"There are studies showing that magnesium can have a laxative effect, suggesting that it may help promote regular bowel movements," says Dr. Nassar. "But studies addressing whether magnesium can improve constipation, specifically, haven't been done."

She adds that, though it may be included as part of a person's larger treatment regimen, magnesium supplementation isn't a first line treatment for constipation.

Is taking a magnesium supplement safe?

The benefits of magnesium supplementation in healthy individuals aren't clear, but Dr. Nassar says that taking a magnesium supplement every day likely isn't unsafe for most people.

Just be sure you're not taking too much magnesium. The maximum dietary allowance for most adults is around 400 mg or less.

And Dr. Nassar doesn't recommend starting a magnesium supplement without first discussing it with your primary-care doctor. He or she will need to review your health history, as well as any medications you're taking.

"Certain medical conditions, like kidney problems, can increase the risk of magnesium build-up and toxicity," warns Dr. Nassar. "And magnesium can decrease the absorption of some medications and interact with others."

And, like all supplements, know that magnesium pills aren't regulated by the FDA — so you'll need to do your research to be sure you're getting a quality product that's undergone testing and been certified by an independent third party laboratory, such as NSF.

Skip the supplements and eat foods high in magnesium instead

"The take-home message I'd share is that usually most people get enough magnesium by eating a healthy diet," Dr. Nassar adds.

Foods that can help you hit your magnesium intake include:

  • Seeds and nuts, particularly pumpkin seeds, chia seeds, almonds and cashews
  • Leafy greens, such as spinach, kale and collard greens
  • Whole grains, including brown rice, oatmeal and whole grain bread
  • Beans and legumes, including black beans, kidney beans, edamame and peanuts
  • Dairy, such as yogurt and certain milks, including cow's milk and almond milk
  • Fish, particularly salmon and halibut
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