A Functional Medicine Expert’s Guide To Magnesium: Foods, Supplements, Deficiency + More

by Dr. Will Cole

Magnesium is one of the most overlooked deficiencies in conventional medicine and one that I see often as a functional medicine practitioner. Even though it is the fourth most abundant mineral in your body and needed for over 300 biochemical reactions, between 50 and 90 percent of people don’t get enough of this nutrient. Close to 60 percent of your body’s total magnesium is located in your bones and the rest can be found in your non-muscular soft tissue and muscles. It’s easy to see why we can’t overlook this deficiency any longer if we want our health to thrive.

So what exactly does magnesium do for us?

Magnsesium is an electrolyte along with potassium, sodium, and calcium. Although it is the least abundant electrolyte, it is just as vital for your body to function optimally. Your body absorbs magnesium in your gut through your small intestine, and then stores it in your body. Excess magnesium is regulated by your kidneys to excrete leftover amounts of this nutrient into your urine.

You’d be surprised how many of our daily body functions depend on magnesium:

1. Energy creation

Your mitochondria is responsible for ATP synthesis – your body’s process for producing energy. With close to 1/3 of your total cellular magnesium located in the mitochondria, low levels can contribute to fatigue.

2. Brain health

MIT research has found that magnesium helps regulate brain receptors that are responsible for memory function. In fact, supplementing with magnesium can improve symptoms of brain fog. It also increases neuroplasticity which works to reduce cognitive decline.

3. Muscle function

Since a large amount of magnesium is stored in your muscles and cells, it works to control neuromuscular signals, helping your muscles to contract and relax. Not having adequate magnesium can lead to spasms and stiffness.

4. Bone health

Magnesium works in conjunction with calcium to transport it from your muscles to other areas of your body – your bones included. Insufficient levels of magnesium can lead to low bone mineral density and contribute to osteoporosis.

5. Mood regulation

Your calming neurotransmitter, GABA, relies on magnesium for its receptors to function properly and reduce stress, lower anxiety, promote relaxation, and improve sleep quality and duration. Magnesium is also considered an NMDA receptor modulator which regulates your excitatory neurotransmitter, glutamate.

GABA and glutamate each have opposite roles and therefore work together to keep your mood steady. Glutamate is a precursor to GABA and excess amounts are converted to GABA. Conversion problems can lead to a surge in glutamate, a drop in GABA, and increased anxiety and depression.

6. Thyroid health

Since magnesium is necessary for thyroid hormone production I often see deficiency as an overlooked contributor for thyroid problems.

7. Inflammation

Almost every modern health problem can be linked to inflammation. Studies have shown that magnesium lowers the inflammatory marker, CRP.

8. Heart health

Magnesium works with calcium to prevent hypertension, stabilize blood pressure, and reduce overall cardiovascular disease risk.

9. Blood sugar

Research has shown a link with lower triglyceride levels and a decreased risk of type 2 diabetes with increased magnesium intake. Since magnesium is excreted through the urine, diabetics typically have lower levels of magnesium since urination is more frequent with this health problem.

It’s amazing that for how much magnesium does for our health, it continues to be one of the more underrated nutrients when looking at underlying causes and treatments of our health problems.

Why Is magnesium deficiency such a problem?

There a few reasons why magnesium is such a common deficiency – and it all has to do with how our modern world has developed:

1. Poor nutrition: Processed, pre-packaged foods that are filled with sugar and devoid of nutrients like magnesium make up the majority of the standard American diet.

2. Medications: Medications like diuretics and antibiotics can decrease our absorption of nutrients by compromising our gut health.

3. Soil depletion: Current agriculture practices have stripped soil of important nutrients, including magnesium, therefore decreasing the amount of nutrients in the food grown in the soil.

4. Gut problems: Chronic gut conditions like leaky gut syndrome can further perpetuate poor magnesium absorption.

Signs of magnesium deficiency

Since magnesium plays a role in so many areas of our body, it makes sense that symptoms of deficiency can manifest in different aspects of our health as well. However, two of the most obvious symptoms of deficiency include:

Muscle cramps and spasms

The seemingly random spasms, cramps, and “charley horses, in your body are one of the most common signs of magnesium deficiency.

Migraines and other headaches

Millions of people experience migraines and other types of headaches on a regular basis. When you experience a migraine, it is due to the tensing up of blood vessels. But magnesium is responsible for relaxing these. It is estimated that 50 percent of migraine sufferers are magnesium deficient and close to 60 percent have genetic mutations that hinder the body’s ability to metabolize magnesium.

Additional symptoms include:

• Osteoporosis
• Restless leg syndrome
• Anxiety
• Depression
• ADHD
• Insomnia
• Constipation

Magnesium Supplements

Since it is difficult to get adequate magnesium through diet alone, supplementation can still be important, especially when trying correct deficiencies.

The same rules apply for magnesium supplements when choosing which one you should take. You’ll want to ensure that the brand you choose is transparent with where it sources its ingredients from and what their manufacturing procedures are. It also needs to be free from additional fillers and ingredients that could also contribute to symptoms.

You also want to take your starting levels into account to determine how much magnesium you need to be taking. Consider working with a functional medicine practitioner who can test your magnesium levels with advanced nutrient labs. Since the majority of your body’s magnesium is stored in your cells and bones, not your blood, this often contributes to the inaccuracy of conventional nutrient labs.

Overall, magnesium is safe to take, but large amounts could potentially cause GI upset and diarrhea. Go off your doctor’s recommendations or start at a lower dose and listen to your body and gradually increase your amount over time. It is important to check your levels every few months to assess how you are improving to determine what you need to do about dosing. But for healthy individuals the daily recommended amounts 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+: 320 mg for women; 420 mg for men
• During pregnancy: 350 to 360 mg
• While breastfeeding: 310 to 320 mg

There is no “right” time to take magnesium. However, due to it’s calming effects, taking it right before bed can be the best way to capitalize on its ability to boost GABA levels and relax muscles. Magnesium can be found in multiple different forms, so you’ll want to consider this when deciding which one will work best for your specific symptoms.

Magnesium chelate

This form is extremely bioavailable and is found in magnesium containing food sources.

Magnesium oxide

This is most commonly used in supplements. Research shows it only has a 4 percent absorption rate so if you are struggling with absorption issues this is probably not your best option. This low bioavailability gives it an intensive laxative effect that makes it a good constipation remedy.

Magnesium citrate

Magnesium is combined with citric acid to make this from. At 16 percent, it has a higher absorption rate than magnesium oxide, but also makes a great choice for relieving constipation.

Magnesium Threonate

Since this form can pass the mitochondrial membrane, research is supporting its ability as a powerful neurological support and a good option for those with depression, anxiety, or brain fog. However, this form is not as readily available.

Magnesium oil

This is a whole new way to boost your magnesium levels. Instead of ingesting it, magnesium oil is placed directly on the skin. This makes it one of the best options for people with gut dysfunctions that limit absorption. Since it also soothes the muscles in your digestive tract, rubbing magnesium oil on your abdomen can combat an upset stomach.

Another way to get in magnesium is by soaking in epsom salts or magnesium flakes. One study showed that after 12 weeks of topical magnesium therapy – soaks and oils – magnesium increased by 25 percent in participants! No wonder soaking in magnesium is so relaxing – your muscles will be relaxed and you’ll be ready to head directly to bed.

Foods to focus on

There are many foods, mostly plant-based, that contain magnesium. This makes it an easy nutrient for most anyone to obtain through diet. Some of the best food sources 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, 1/8 cup: 92 mg
• Cashews, 1/4 cup: 91 mg
• Almonds, 1 ounce: 80 mg
• Black beans, 1/2 cup: 60 mg
• Avocado, 1 medium: 58 mg
• Salmon, 1 filet: 53 mg
• Kefir, 1 cup: 50 mg
• Figs, 1/2 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, work with a functional medicine doctor to assess your levels in order to get your health back on track. For the rest of us, don’t underestimate the need for this nutrient!

If you want to learn more about your own health case please check out our free health evaluation. We offer in person as well as phone and webcam consultations for people across the country and around the world.

Photo: Stocksy

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

Our articles may include products that have been independently chosen and recommended by Dr. Will Cole and our editors. If you purchase something mentioned in this article, we may earn a small commission.