In recent years, magnesium supplements have come into the spotlight as a possible way to improve sleep quality and mood. This micronutrient is also pivotal to metabolic function, influencing how your body uses and produces energy. A 2018 paper declared subclinical magnesium deficiency “a public health crisis” and noted that most people in modern societies are at risk for magnesium deficiency.
Here, we’ll dive into the role of magnesium in metabolic health and how to make sure you’re getting enough.
What Is Magnesium, and How Does It Affect Metabolic Health?
Magnesium is found throughout the human body as a positively charged ion. About half the body’s magnesium is stored in the bones. The rest is located in the blood and other tissues, where it acts as a cofactor in more than 300 enzyme systems that control heart rate and blood pressure, muscle and nerve cell function, stress pathways, and crucial metabolic processes like glucose control, insulin sensitivity, and energy production.
Magnesium works to stabilize enzymes for the production of adenosine triphosphate (ATP), which is known as the energy currency of cells. When the body needs cellular energy, ATP binds to a magnesium counter ion to become biologically functional. Magnesium also plays a role in helping glucose transporter proteins (like GLUT4) move glucose across cell membranes where it can be used as energy. And it promotes autophosphorylation, a process that causes insulin receptors to turn on, which helps regulate insulin sensitivity.
Hypomagnesemia, or clinically low magnesium levels, has been strongly associated with Type 2 diabetes in various meta-analyses. Clinical studies show that people with Type 2 diabetes and low magnesium levels tend to have more rapid disease progression and are more likely to experience complications from diabetes. One study described the link between low magnesium levels and Type 2 diabetes as a “vicious circle” in which hypomagnesemia causes insulin resistance, and insulin resistance reduces magnesium levels in the body, leading to more insulin resistance.
Since magnesium plays a role in so many physiological and metabolic processes, a deficiency has been associated with a wide range of other health issues, including tension-type headaches, depression, and heart disease.
How Much Magnesium Do You Need?
According to the National Institutes of Health, the daily magnesium requirements are:
- Men, 19 to 30: 400 milligrams (mg)
- Men, 31+: 420 mg
- Women, 19 to 30: 310 mg (350 mg if pregnant)
- Women, 31+: 320 mg (360 mg if pregnant)
If your healthcare provider recommends a supplement, it’s essential to learn about dosage. Many health resources, including the Mayo Clinic, recommend a maximum of 300-400 mg of supplemental magnesium daily. Functional medicine doctors such as Dr. Mark Hyman, a Levels Health advisor, suggest a higher dose, saying that because the vast majority of the population is deficient in magnesium due to lifestyle and environmental factors, most people will benefit from closer to 400-1,000 mg of magnesium a day in supplement form. Another study That said, this amount exceeds the tolerable upper limits from the National Institutes of Health (NIH), so it’s important to keep in mind that dosing will vary based on your individual health, so it’s best to work with a medical professional to identify the best dose for you.
How Do You Test for a Magnesium Deficiency?
Diagnosing a deficiency in magnesium is challenging for a few reasons, starting with the fact that there is no gold standard test for a magnesium deficiency in your cells. A blood test can measure magnesium levels in the blood, and hypomagnesemia is diagnosed when serum magnesium levels are less than 0.75 mmol/l. However, the magnesium level in the blood does not reflect the amount in the cells, which contain nearly 100-fold more magnesium. Because of these challenges, deficiencies have historically been diagnosed by assessing a patient’s history, clinical symptoms, and the results of blood tests.
Because of this, many cases of magnesium deficiency go undiagnosed. At the same time, according to Dr. Hyman, the vast majority of people are at risk for a deficit due to factors including:
- Environmental changes that have caused magnesium soil depletion
- The abundance of processed foods in our diet (processing can decrease magnesium levels by 80 percent)
Certain chronic diseases such as diabetes and hypertension are associated with magnesium deficiency, as well as certain medications, such as proton pump inhibitors and diuretics, which both affect magnesium balance in the body.
Signs of a severe deficiency, such as one caused by a medication or serious electrolyte imbalance, include numbness, tingling, muscle cramps, seizures, personality changes, and abnormal heart rhythm. If you experience any of these symptoms, seek emergency care.
A mild magnesium deficiency can be challenging to tease out because the signs are nonspecific, including:
- Anxiety and nervousness
- Muscle weakness
- Nausea or vomiting
- Loss of appetite
If you experience any of these, consider your risk factors. The following increase the risk of a magnesium deficiency:
- Diabetes and prediabetes: High blood sugar can trigger increased urination, which can lead to more magnesium lost through your urine. Diabetes medications such as metformin may also decrease magnesium levels. The exact mechanisms are unknown, but studies show that hypomagnesemia occurs in as many as 48% of patients with Type 2 diabetes.
- Gut health conditions: Research shows that celiac disease patients can have decreased levels of magnesium. This is likely due to a loss of functioning of the brush border proteins—proteins located in the wall of the intestines that regulate the transport of nutrients from the digestive system into the bloodstream—needed to absorb magnesium and the fact that gluten-free grains contain less magnesium than gluten-containing ones.
- Alcohol abuse: Alcohol acts as a diuretic, causing a drastic increase in urinary excretion of magnesium. Most of this research on magnesium deficiency and alcohol intake has been performed on those with alcoholism, so it’s unknown whether mild or moderate alcohol consumption can also lead to an increased risk for deficiency.
- Older age: As we age, the ability to absorb magnesium decreases while the amount of magnesium the kidneys excrete increases. Aging has been associated with an increase in magnesium deficiency.
What are the Best Foods for Magnesium?
Experts say eating more magnesium-rich foods is the best first step to correct magnesium deficiency since there is little risk of consuming so much food-based magnesium that you experience side effects.
Some of the top dietary sources of magnesium include:
- Seeds: Pumpkin seeds (156 mg per ounce, roasted) and chia seeds (111 mg per ounce)
- Nuts: Almonds (80 mg per ounce, dry roasted) and cashews (74 mg per ounce, dry roasted)
- Leafy greens vegetables: Spinach (48 mg per 2 cups raw)
- Legumes: Black beans (60 mg per 1/2 cup, cooked) and edamame (50 mg per 1/2 cup, shelled and cooked)
- Grains: Quinoa (60 mg per 1/2 cup, cooked) and shredded wheat (65 mg per cup)
Other ways to optimize magnesium levels are to make the foundation of your diet minimally processed or fresh foods. You can also opt for frozen foods, though one study showed that frozen leafy greens lose some magnesium when reheated.
What About Magnesium Supplements?
Magnesium supplements can help eliminate magnesium deficiency and show some promise to improve health ailments that have been linked to magnesium deficiency, such as:
- Metabolic syndrome: A recent meta-analysis of nearly 25,000 people found that an increase of 100 mg of magnesium per day was associated with a 17 percent decreased risk of metabolic syndrome.
- Anxiety: A systematic review of 18 studies suggests magnesium supplements have a beneficial effect on anxiety. However, the authors note the quality of evidence is still poor (for example, even though they had positive results, some of the studies tested magnesium in addition to other supplements, like vitamin B6, and others were unpublished). The results are promising, but we need more research into this connection.
- Sleep issues: Quite a few studies have explored the relationship between magnesium deficiency and sleep issues, anxiety, and fatigue, which often occur together. One systematic review of nine studies showed an association between magnesium status and sleep quality (measured by tracking daytime falling asleep, sleepiness, snoring, and sleep duration) in observational studies, but randomized clinical trials reported contradictory findings. A 2021 systematic review and meta-analysis showed that taking a magnesium supplement was linked to falling asleep 17 minutes faster and that total sleep time was improved in the magnesium supplementation group, but the improvement was not statistically significant.
- Muscle cramps: A meta-analysis of seven randomized controlled trials on more than 300 participants compared magnesium 300 to 900 mg/day to placebo and showed no benefit in some populations but a small positive effect on nocturnal leg cramps in pregnant women.
Supplementation with magnesium is generally considered safe. The kidneys have a great capacity for regulating magnesium levels in the body—they can filter up to 2,400 mg of magnesium per day—and can excrete up to 70 percent of that magnesium through urine if there is too much in the body. That said, too much magnesium in supplement form, especially in certain forms and for those with impaired kidney function, can cause side effects. If you take supplements, look for magnesium citrate, magnesium glycinate, magnesium taurate, magnesium aspartate, magnesium malate, magnesium succinate, and magnesium fumarate, which according to recent advice from Dr. Hyman, are the forms of magnesium that are best absorbed and the least likely to cause side effects. Magnesium L-threonate can also be beneficial for neurological health. Magnesium carbonate, gluconate, and oxide are poorly absorbed and can lead to side effects like diarrhea, nausea, and stomach cramps.
Keep in mind that magnesium supplements have the potential to interact with certain medications, including:
- Osteoporosis drugs like Fosamax
- Antibiotics such as demeclocycline or Cipro
- Diuretics like Lasix or Edecrin
- Proton pump inhibitors such as Nexium or Prevacid
To best support optimal magnesium levels and prevent a deficiency, take stock of your potential risk factors for a deficiency and invest in appropriate solutions to optimize your levels, whether that means magnesium-rich foods or supplementation.