There are many nutrients that your body needs every day to function optimally, including carbohydrates, protein, fat, vitamins, minerals and water. While there are several minerals that are key to your overall health, magnesium is a particularly important mineral that has some specific implications for brain health.
What Is Magnesium?
Magnesium is the fourth most abundant mineral in the body — after calcium, sodium and potassium — and plays a fundamental role in the regulation of various biological processes that are necessary to function well.
This mighty mineral is used in more than 300 enzyme systems within the body that contribute to:
— Contracting muscles, including the heart.
— Controlling calcium levels inside cells.
— Creating energy.
— Keeping bones healthy and strong.
— Making DNA and RNA.
— Regulating blood pressure.
— Synthesizing protein.
— Transporting electrolytes across cell membranes.
Magnesium also plays an important role in maintaining ideal levels of other minerals — like calcium, potassium and zinc — in the body. This mineral can be found in foods, supplements and even some medicines, such as antacids and laxatives.
The recommended dietary allowance of magnesium for adults is 400 to 420 milligrams each day for men, and 310 to 320 milligrams each day for women. Pregnant women need between 350 and 360 milligrams of magnesium daily to maintain sufficient levels of the mineral during pregnancy, which has been shown to reduce the risk of certain pregnancy related complications, like preeclampsia, and may increase birth weight, according to studies. Too much magnesium beyond the daily allowance may cause side effects, such as irregular heartbeat, low blood pressure, confusion, slowed breathing and — in rare cases — death.
Your kidneys are largely responsible for maintaining magnesium homoeostasis, excreting excess magnesium when your levels are high, but also reducing magnesium excretion when your levels are low. For healthy people, the risk of symptomatic magnesium deficiency is low because of this, but certain populations may be at a greater risk of deficiency. These include:
— Older adults.
— Patients with uncontrolled diabetes.
— Patients with digestive disorders that cause malabsorption of nutrients from food.
— Those who take certain medications, including proton pump inhibitors (such as omeprazole for gastroesophageal reflux disease) and loop or thiazide diuretics (such as furosemide, hydrochlorothiazide and chlorthalidone, which may be used for congestive heart failure, high blood pressure and other cardiac conditions).
— Those with chronic alcoholism.
While your doctor can perform a blood test to measure blood magnesium levels, blood levels do not accurately reflect magnesium levels throughout the body.
“More than half the body’s magnesium is stored in bones, so the test cannot give you a complete picture,” explains Marion Nestle, a professor emerita of nutrition, food studies and public health at New York University in New York City.
Because the symptoms of magnesium deficiency — such as nausea, vomiting, fatigue, weakness and loss of appetite — are also common symptoms of other health issues, it is important to speak to your doctor to help determine the precise cause of your symptoms.
Magnesium for Brain Health
A growing body of evidence suggests that maintaining proper levels of magnesium protects against chronic disease and supports brain health, while low magnesium is increasingly linked to a risk of neurological and psychiatric disorders and impaired disease management.
“As such, magnesium plays a pivotal role in brain health,” says Dr. Michael del Junco, an internal medicine specialist with Providence St. Joseph Hospital in Orange County, California.
But how exactly does this mineral help the brain?
Magnesium is essential to ensuring the normal function of neurons and helps regulate neurotransmitters, which are the chemical messengers that help the cells of the brain communicate with each other, and with the rest of the body. Two neurotransmitters in particular — glutamate and gamma-aminobutyric acid, or GABA — are dependent on appropriate levels of magnesium.
“Glutamate plays a major role in normal brain functioning, including shaping learning and memory,” says Candace Pumper, a staff dietitian with the Ohio State University Wexner Medical Center in Columbus. “For the brain to function properly, glutamate levels need to be tightly controlled. Any imbalance can disrupt nerve cell communication.”
Low levels of magnesium can lead to excess glutamate in the brain. When this happens, nerve cells can become overexcited, leading to nerve cell damage and/or death, a condition known as glutamate excitotoxicity that has been implicated in many neurodegenerative conditions, such as amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, epilepsy, migraines, depression and chronic pain.
In fact, a 2018 study published in the journal Nutrients suggests that magnesium has a protective effect in conditions of chronic pain, anxiety and stroke. While more research is needed, researchers stated that there is good potential for magnesium to be beneficial for brain health.
One recent study published in the European Journal of Nutrition found that more magnesium in our daily diet is linked to better brain health as we age, especially for women. The study included 6,001 healthy male and female participants ages 40 to 73 who were asked to record their daily estimated magnesium intake over 16 months. The results found the brain age of those who consumed over 550 milligrams of magnesium each day is approximately one year younger by the time they reach 55 compared with someone who consumed a normal magnesium intake of about 350 milligrams a day.
“Our study shows a 41% increase in magnesium intake could lead to less age-related brain shrinkage, which is associated with better cognitive function and lower risk or delayed onset of dementia in later life,” says lead author Khawlah Alateeq of the Australian National University’s National Centre for Epidemiology and Population Health, in a statement. “Higher dietary magnesium intake may contribute to neuroprotection earlier in the aging process and preventative effects may begin in our 40s or even sooner.”
[READ: Best Foods for Your Brain]
Magnesium Food Sources
Magnesium can be found in a wide range of food sources.
“Magnesium deficiencies ought to be — and are — extremely rare among people who eat vegetables,” Nestle says. “If a food has fiber, it has magnesium, so this includes fruits, vegetables, nuts and grains.”
Some of the best options include the following items, as quantified by the National Institutes of Health:
— Chocolate or cocoa.
— Greens and vegetables.
— Low-fat dairy products and soy.
— Nuts and seeds.
The amount of magnesium found in these foods can fluctuate depending on local agricultural practices, how they’re fertilized and how they’ve been processed, refined or cooked, Pumper says.
Some foods, such as some breakfast cereals, are fortified with extra magnesium. Pumper adds that some bottled mineral and tap water sources can contain magnesium and can “provide portions of the RDA of this mineral. But the amount varies by source and brand with a range of 1 milligram per liter to 120 milligrams per liter.”
Should I Take a Magnesium Supplement?
If your magnesium levels are normal, you should avoid supplementation.
“No current evidence suggests that magnesium supplementation will provide any measurable benefit to a patient with normal magnesium levels,” Del Junco explains.
However, if you’re deficient in this nutrient, experts encourage increasing your magnesium intake through your diet first. Only if you’re unable to absorb enough magnesium from your diet should you consider a supplement.
“Magnesium supplementation can certainly help fill gaps in a nutrient-deficient diet, but the challenge is discerning which products to choose,” Pumper says. “For consumers, talking with your doctor before adding a magnesium supplement to your routine is a good first step.”
How to Choose a Magnesium Supplement
If you and your health care provider determine that supplementation is a good idea, Pumper recommends considering the following when choosing a product:
Choose your form of magnesium
Magnesium supplements are available in different forms, each with differing absorbability, benefits and effects on the body. While common forms include magnesium citrate, magnesium oxide, magnesium glycinate, magnesium chloride and magnesium sulfate, magnesium citrate is the most readily absorbed form of magnesium supplement when taken orally and is gentle on the stomach.
“Magnesium citrate is often used to address low levels of magnesium and may also be effective as an acute treatment option for migraine headaches,” Pumper says.
Check other medications you’re taking
Supplements can sometimes interact negatively with other medications or supplements you may be taking, so it’s very important to check with your health care provider before adding any herbal or dietary supplement product.
Magnesium supplements, in particular, can interact with and decrease the absorption of certain medications, including antibiotics, diuretics, proton pump inhibitors, bisphosphonates (which are used to treat bone conditions like osteopenia and osteoporosis) and high doses of zinc (above 142 milligrams per day).
Inspect product quality
Pumper recommends selecting products that have been tested for safety and quality by trusted third-party certification organizations, such as NSF International, ConsumerLab.com or U.S. Pharmacopeia.
Consider other medical conditions
People who have chronic kidney disease should not take magnesium supplements, as they can cause high amounts of magnesium to accumulate in the blood and lead to muscle weakness.
Too much magnesium from food rarely poses a risk because of the kidney’s ability to eliminate the excess in healthy adults, but high doses from supplements or medications can cause side effects, including abdominal cramping and diarrhea.
“If you experience these symptoms, reduce your daily dose,” del Junco says.
As always, contact your health care provider for additional guidance.
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Update 08/10/23: This story was previously published at an earlier date and has been updated with new information.