On magnesium and supplements. Originally published 27 Jan 2017. Last updated 7 Oct 2020.
What is Magnesium?
Magnesium is a mineral and serves many important functions in the body. It is actually a mineral and serves many important functions in the body.
It’s been estimated that magnesium is involved in over 300 metabolic processes in the body, ranging from:
- helping us build muscle
- making sure our bones and strong and healthy
- helping us manage our blood sugar
- even keeping our blood pressure in check
Given this, it becomes clear why some may want to consider supplementing magnesium. But, before I get to that, I have to mention…
It’s been estimated that magnesium is involved in over 300 metabolic processes in the body ranging from helping us build muscle, making sure our bones and strong and healthy, helping us manage our blood sugar, and even keeping our blood pressure in check.
How Much Magnesium Do We Need Each Day?
It differs slightly for men and women:
- For most healthy women, somewhere between 310-360 mg per day is recommended
- For otherwise healthy men, between 400-420 mg per day
The question is, do most people meet these daily magnesium recommendations?
Do Most People Meet Daily Magnesium Recommendations?
According to some data sources, yes… others, no. Clear as mud, right?
The problem is, these data are often based on surveys. For example, researchers will mail a survey to a bunch of people that have agreed to be in their study. One of the survey questions will ask something like, “How often do you consume green leafy vegetables? How often do you consume almonds? How often do you consume black beans?”
All of these foods are high in magnesium, so by asking about their intakes of these foods, they can determine whether folks are getting enough magnesium in their diets. The problem is, often people either can’t accurately remember how often they consume these foods. I’m a dietitian and I can’t remember what I ate 3 days ago, let alone try and accurately report how often I consume magnesium-rich foods.
So, it’s common for people to forget how often they consume certain foods and may over or underestimate their intakes.
Blood Test for Magnesium Deficiency
Another way to help determine whether folks are getting enough nutrients in their diets is to have them go in for a blood test.
For example, it is common for doctors to run a blood test that looks at vitamin D levels because we’re learning that many adults living in the U.S. are vitamin D deficient.
Unfortunately, with magnesium, we can’t run a simple blood test to see if you’re deficient. This is because there’s actually not a whole lot of magnesium floating around in the bloodstream. Instead, it’s sitting inside our cells like our muscle cells and in our bones.
Unless we were to remove some of your muscle cells or your skeletal structure to see how much magnesium you have stored up, we really don’t know whether you’re deficient.
How Common is Magnesium Deficiency?
According to the National Institutes of Health, most “otherwise healthy” adults probably get enough magnesium each day. This is because it is found in many foods we eat regularly. Certain groups are more likely to have a magnesium deficiency:
- those on medications that prevent magnesium from being absorbed by the gut
- those with GI disorders like Crohn’s disease or active ulcerative colitis or Celiac disease
- those with type 2 diabetes
Some older adults may not be getting enough magnesium also, but much of that depends on their diet.
Types of Magnesium Supplements
Magnesium can be found in various forms. When strolling down the aisle of your local pharmacy, you may encounter a product called Milk of Magnesia®.
This is an over-the-counter laxative. That word “magnesia” is in reference to, yup, magnesium. So too much magnesium can act as a laxative. Milk of Magnesia is often found as a liquid and is in the form of magnesium hydroxide.
Magnesium supplements can also be found as magnesium hydroxide, magnesium oxide, magnesium chloride, magnesium gluconate, magnesium citrate, magnesium orotate, and more. According to ConsumerLab.com, magnesium oxide may not be absorbed as well as magnesium citrate or magnesium chloride.
And, possibly because it’s not well absorbed, the other downside to magnesium oxide is that it may be more likely to act as a laxative. Magnesium chloride is best absorbed when taken in liquid form, though. Magnesium orotate is far more expensive, but doesn’t seem to provide any additional benefits when compared to other available forms of magnesium supplements.
Basically magnesium citrate and magnesium chloride are the most commonly recommended forms.
Should Everyone Take Magnesium Supplements?
Would I recommend most folks supplement magnesium? Probably not.
Researchers are discovering that supplementing likely will not improve your blood pressure, lower your risk for heart disease or stroke, reduce the frequency of headaches and migraines, or help with managing blood sugar. The American Diabetes Association went on record stating that there isn’t enough evidence to recommend magnesium supplementation at this time to help manage blood sugar.
Luckily, it is possible to consume enough magnesium through your diet alone. Those foods that are great sources of magnesium include nuts (like almonds, peanuts, and cashews), beans, soy (like edamame, tofu, and soymilk), green leafy vegetables (like spinach), avocado, whole grain breads, and dairy products. In fact, my daily afternoon snack of a ½ cup of almonds, peanuts and cashews gets me about halfway to the 400 mg daily goal for males.
Magnesium Supplements: Conclusion
It is possible to consume enough magnesium through your diet alone.
Those foods that are great sources of magnesium include:
- nuts (like almonds, peanuts, and cashews)
- soy (like edamame, tofu, and soymilk)
- green leafy vegetables (like spinach)
- whole grain breads
- dairy products
Most people don’t need a magnesium supplement unless they have a GI disorder, are on certain medications, or follow a really strict diet. But as always, I would encourage you to contact your doctor if you aren’t sure before supplementing on your own.
For me, I know that my intake is likely just fine because every day — around 3 p.m. I grab a handful of unsalted mixed nuts (which includes almonds, pecans, cashews, walnuts, and peanuts) and have that as a snack. That snack alone gets me about halfway towards my recommended daily intake.