Magnesium Supplements: Everything You Need To Know About Deficiency, Supplements, Foods & More
One of the top nutrient deficiencies I find as a functional medicine practitioner and also one the most overlooked in conventional medicine is that of magnesium. Magnesium is the fourth most abundant mineral in your body yet one of the most common nutrient deficiencies in America. In fact, between 50 and 90 percent of people lack enough of this vital nutrient. Of your body’s total magnesium, 60 percent is located in your bones with the rest in your muscles and nonmuscular soft tissue. Since your body needs magnesium for close to 300 extremely important biochemical reactions, magnesium is not something that should be overlooked when working to achieve optimal health.
So what exactly does magnesium do for our health?
Magnesium is considered an electrolyte along with calcium, potassium, and sodium. It is absorbed in your gut, mainly in the small intestine, and then stored in your body. Any excess magnesium is controlled by your kidneys, which excrete any leftover into your urine. Of the electrolytes, magnesium is the least abundant; however, it is vital to your body function.
You’d be surprised just how many of our most important body functions that we often take for granted rely on magnesium:
1. Magnesium and energy creation.
2. Magnesium and brain health.
3. Magnesium and muscle function.
Since magnesium is primarily located in your cells and muscles, it is responsible for controlling neuromuscular signals. Magnesium helps your muscles to contract as well as relax. So if you don’t have enough, it can contribute to stiffness and spasms.
4. Magnesium and bone health.
Magnesium works together with calcium to transport it from your muscles to the rest of your body, including your bones. Low magnesium levels can contribute to lower bone mineral density and can lead to osteoporosis.
5. Magnesium and mood regulation.
GABA is your body’s calming neurotransmitter that also helps produce your "happy" neurotransmitter, serotonin. Magnesium is essential for your brain’s GABA receptors to function properly, which promotes relaxation, reduces stress, lowers anxiety, and even improves sleep. It is considered an NMDA receptor modulator that also works to regulate your excitatory neurotransmitter, glutamate.
Glutamate and GABA work together to keep your mood steady since they each have opposite roles. In fact, glutamate is actually considered a precursor to GABA with excess amounts converted to GABA. When there are problems with conversion, glutamate rises, GABA drops, and anxiety and depression follow.
6. Magnesium and thyroid health.
7. Magnesium and inflammation.
Inflammation has been linked to almost every modern health problem. According to research, magnesium can lower the inflammatory marker CRP.
8. Magnesium and heart health.
9. Magnesium and blood sugar.
Magnesium plays an important role in glucose metabolism. Multiple studies have shown a link between higher magnesium intake and a decreased risk of type 2 diabetes as well as lower triglyceride levels. Also, since magnesium is excreted through urine, those with diabetes tend to have lower levels of this nutrient already due to more frequent urination.
For how much magnesium does for us, it is surprisingly one of the most underrated nutrients when it comes to examining levels for deficiencies to help determine the underlying cause and subsequent treatment of our symptoms.
Why are so many people magnesium deficient?
There are many reasons magnesium is such a common deficiency in our society—and it all has to do with the way our world is set up:
- Poor nutrition: The standard American diet is filled with processed, prepackaged foods loaded with sugar and devoid of any nutrients that whole foods provide.
- Medications: Certain medications like antibiotics and diuretics decrease our absorption of the already little magnesium we are getting through our diets.
- Soil depletion: Our new agriculture methods have increasingly stripped soil of its important nutrients—magnesium included—which decreases the nutrients of the food grown in that soil.
- Chronic gut problems: Conditions such as leaky gut syndrome compromise magnesium absorption even further.
Signs of magnesium deficiency.
Since magnesium is crucial to the proper function of so many different areas of our body, it only makes sense that symptoms of deficiency can be seen over many aspects of our health, but two of the most obvious symptoms are:
Muscle cramps and spasms.
One of the most common signs of magnesium deficiency is the seemingly random cramps, spasms, and "charley horses" that come and go throughout your body.
Migraines and other headaches.
Millions of people experience migraines and other headaches on a monthly basis. Magnesium is responsible for relaxing the blood vessels in the brain that tense up during migraines. It is estimated that 50 percent of migraine sufferers are magnesium deficient, and 60 percent have genetic mutations that decrease the body’s ability to metabolize magnesium.
Other symptoms of deficiency can include:
- Restless leg syndrome
How to choose a magnesium supplement.
It’s difficult to get the amount of magnesium your body requires entirely through diet, so supplementation is often still an important part of your wellness routine, especially when trying to replenish deficiencies.
When choosing a magnesium supplement, the same rules apply as when looking for any other quality supplement. You’ll want to make sure that the brand you choose is transparent with its sourcing and manufacturing procedures in addition to being free from other fillers and added ingredients that could further perpetuate symptoms, especially for highly sensitive individuals.
It is also important to take your starting levels into account to determine exactly how much magnesium you should be taking. Consider working with a functional medicine practitioner to get your magnesium levels tested since conventional nutrient labs aren’t always accurate because most of your body’s magnesium is stored in your bones and cells rather than blood. A more advanced nutrient lab can give better insight as to where you stand.
In general, magnesium is safe to take but can potentially cause diarrhea and GI upset if you are taking too much for your body. Go off your doctor’s recommendations or start at a lower dose and listen to your body and slowly increase your amount over time. Continue to get your levels checked every few months to see how you are improving and if you are able to reduce your dose to keep your levels steady. But the recommended daily amounts of magnesium for healthy individuals are:
- Infants to 6 months: 30 mg
- 7 to 12 months: 75 mg
- 1 to 3 years: 80 mg
- 4 to 8 years: 130 mg
- 9 to 13 years: 240 mg
- 14 to 18 years: 360 mg for women; 410 mg for men
- 19 to 30 years: 310 mg for women; 400 for men
- 31-plus: 320 for women; 420 for men
- During pregnancy: 350 to 360 mg
- While breastfeeding: 310 to 320 mg
There is no "set" time to take magnesium; however, if you want to capitalize on its calming effects, taking it right before bed is best since it relaxes muscles and boosts GABA levels to help lull you to sleep. There are actually a few different forms of magnesium, so when looking for a supplement, you’ll want to take this into consideration as well to determine which is the best option for your particular symptoms:
This is the form found in foods and is highly bioavailable.
This is the most common form used in supplements. It is not as easily absorbed as other forms, though, so if you are dealing with absorption issues or trying to correct deficiencies, this may not be the best option. Studies have shown that this form has only about a 4 percent absorption rate. This lower bioavailability, though, makes it a good option to relieve constipation due to its intense laxative effect.
This form is magnesium combined with citric acid. It also works well for constipation but has a slightly higher absorption rate than magnesium oxide at 16 percent.
Since it is more bioavailable than other forms, it has less of a laxative effect, making it a better choice to use for improving deficiencies.
Research has shown the most promise with this form for its ability to help with neurological support due to its ability to pass the mitochondrial membrane. Unfortunately, this form is harder to come by but would be a great choice for those looking to help with anxiety, depression, or brain fog.
This is a whole other way to give your magnesium levels a boost. Instead of ingesting it, you rub magnesium oil on your skin, making it a great option for those with gut dysfunctions like leaky gut syndrome, which inhibits absorption. And because it also regulates digestion and soothes the muscles in your gut, spraying magnesium oil directly on your abdomen is a great way to combat an upset stomach.
Another way to get magnesium topically is through soaking in magnesium flakes or Epsom salts. Research has shown that after 12 weeks of topical therapy, both oil and soaks, magnesium levels in participants increased by 25 percent! No wonder soaking in a tub filled with magnesium is such a relaxing experience. Your muscles will be less tense, and you’ll be ready to head off to bed before you know it!
Magnesium-rich foods to focus on.
There are many foods, mostly plant-based, that contain magnesium, making it an easy nutrient for anyone to get in through their diet. Some of the foods with the highest magnesium content include:
- Spinach, 1 cup: 157 mg
- Swiss chard, 1 cup: 154 mg
- Mung beans, 1 cup: 97 mg
- Dark chocolate, 1 square: 95 mg
- Pumpkin seeds, ⅛ cup: 92 mg
- Cashews, ¼ cup: 91 mg
- Almonds, 1 ounce: 80 mg
- Black beans, ½ cup: 60 mg
- Avocado, 1 medium: 58 mg
- Salmon, 1 fillet: 53 mg
- Kefir, 1 cup: 50 mg
- Figs, ½ cup: 50 mg
- Banana, 1 medium: 32 mg
- Broccoli, 1 cup: 32 mg
- Brussels Sprouts, 1 cup: 32 mg
If you are experiencing any symptoms of magnesium deficiency, seek out a functional medicine doctor to assess your levels. And for the rest of us, don’t underestimate the need for this nutrient, and load up your plate with some of these magnesium-rich foods!
And are you ready to learn more about what anxiety, brain health, and your diet all have in common? Register now for our FREE Functional Nutrition Webinar with Dr. Mark Hyman.