Are you having issues with sleep, mood, muscle cramps, weakness, high blood pressure, skipped heartbeats, or constipation? You could be low in magnesium. About 50 percent of Americans don’t consume adequate amounts of this beneficial mineral. A diet rich in magnesium is high in nuts, seeds, legumes (like beans and peanuts), spinach, and other leafy green vegetables. But even among my patients who eat a very healthy diet, many of them seem to feel better when I start them on a daily magnesium supplement.

Magnesium is an essential mineral and electrolyte that serves over 300 functions, including catalyzing enzymatic reactions responsible for everything from creating DNA and generating energy in your mitochondria to optimizing the function of nerves and muscles. It also plays a central role in hormonal balance; for instance, magnesium affects estrogen levels and stress hormones and is needed to make thyroid hormone. Moreover, having low levels of magnesium increases your risk of weight gain, insulin resistance, high blood sugar, type 2 diabetes, chronic inflammation, and heart disease.

Magnesium and Heart Health

Magnesium is one of the most heart-friendly minerals. Sodium is magnesium’s evil twin; excess salt intake increases blood pressure and swelling, and also predisposes to stroke and heart failure. Unfortunately, most people eat too much sodium and not enough magnesium. Oral magnesium acts as a natural calcium channel blocker, increases nitric oxide, improves endothelial dysfunction, and relaxes/dilates arteries and veins. All these actions of magnesium help to make it an effective therapy to lower blood pressure and normalize left ventricular hypertrophy (abnormal thickening of the heart muscle), particularly when done in conjunction with increasing intake of potassium and reducing sodium intake. Magnesium supplementation increases the effectiveness of blood pressure-lowering meds. The dose of magnesium required to reduce blood pressure is 500 to 1000 mg/day.

A deficiency of magnesium can also cause dysfunction of the lining of the blood vessels, predisposing to spasms of the arteries and abnormal blood clotting. Magnesium is essential for activating the ion pump that maintains the gradient across the cell membrane, keeping the sodium out of the cell and the potassium inside the cell. When magnesium levels are low, it allows excess sodium and calcium to seep into the cells. This is one of the ways in which low magnesium levels make the cells of the heart more irritable, which can increase the risk for cardiac rhythm disturbances like ventricular tachycardia (VT) and even sudden cardiac arrest. In fact, for some serious cardiac rhythm disorders, giving 2 grams of intravenous magnesium can be a life-saving intervention.

The Daily Allowance for magnesium is about 300 to 350 mg for women and 420 to 480 mg for men.  American women consume an average about 230 mg of magnesium per day, and men about 300 mg per day. For comparison, our hunter-gatherer ancestors consumed about 600 mg of magnesium daily. For various reasons such as depleted soil from corporate farming and food processing that strips magnesium out of whole foods, it can be difficult to rely on diet alone forgetting enough of this key mineral. Many factors contribute to magnesium deficiency, including a diet based on refined and processed foods, diseases including kidney disease, gastrointestinal disorders, cancer, medications (including diuretics, birth control pills, proton pump inhibitors), excess alcohol, stress, frequent use of sauna and steam baths, strenuous exercise, and vitamin D deficiency.

People who aren’t getting enough magnesium in their food tend to feel better when they take a supplement. I often prescribe anywhere from 300 to 1000 mg of magnesium daily to reduce muscle soreness or cramps, to facilitate sleep, and treat/prevent constipation. Magnesium is also being studied for its potential benefits in the treatment of mild cognitive impairment, where it may improve memory and overall mental functioning.

Magnesium is one of the safest and most effective sleep therapies. I personally take two capsules of a magnesium supplement just before bedtime on most nights and find that it produces a gentle calming effect on my mood and helps me sleep more deeply. Magnesium comes in many forms, but the best for improving sleep are magnesium glycinate, magnesium taurate, or magnesium threonate.

Because magnesium citrate and magnesium oxide are poorly absorbed forms of magnesium, they are good for improving bowel function in people who deal with constipation. Indeed, increasing your intake of water, magnesium, and dietary fiber like psyllium (Metamucil), is the best strategy to avoid or treat constipation and improve bowel regularity. We generally recommend that people take about 200 to 400 mg daily of magnesium, but for more severe cases of constipation, you can use higher doses of magnesium up to 800 or 1000 mg daily as needed.

Magnesium is important for activating vitamin D and has a protective role against oxidative stress. Furthermore, inadequate magnesium levels can lead to depressed immune responses, whereas restoring normal magnesium levels can improve immunity. Considering that magnesium and vitamin D are important for immune function and resilience against infection, a deficiency in either of these nutrients may contribute to severe illness with COVID infection.

You should design your diet to contain plenty of magnesium. The foods highest in magnesium—nuts, seeds, leafy greens, yogurt, legumes, and dark chocolate— also tend to be among the healthiest foods for many other reasons. If you are experiencing muscle cramps, increasing your intake of magnesium and potassium from vegetables, fruits, and legumes is often effective for relieving these and other muscle-related symptoms.

I have become personally enamored with taking a warm mineral bath with magnesium salts to soothe sore muscles and joints. For thousands of years, hot springs and mineral baths have been a popular way to relax, de-stress, and improve overall health. The Romans built spas by natural hot springs and relied upon the mineral baths for their restorative and rejuvenating effects. Magnesium is the secret behind the healing powers of a hot mineral spa or an Epson salts bath. The dissolved magnesium soaks into and rejuvenates your skin, muscles, and joints, and even gets absorbed into your bloodstream, helping to boost the levels of this health-giving mineral.

Options in Magnesium Supplements

We encourage a “food first” strategy but acknowledge that many of our patients may need additional magnesium in supplement form to feel and function best. You have many different formulations of magnesium to choose from. One of the most common is magnesium oxide, which tends to be less well absorbed, and thus is effective for relieving constipation. Too high a dose of magnesium oxide can cause bloating and loose stools or diarrhea. Magnesium citrate is another great option for people with constipation, as it will produce a gentle laxative effect by pulling water into the intestines to make your bowel movements softer and easier to pass.

Magnesium glycinate and magnesium taurate are my favorite forms of supplemental magnesium. These forms are absorbed in the gut and pass the blood-brain barrier where they interact with neurotransmitters (chemicals in your brain) like serotonin and GABA, to boost mood and induce feelings of calm. Additionally, magnesium glycinate and taurate can be helpful for lowering blood sugar levels and reducing overall inflammation in the body and brain. These forms of magnesium are less likely to produce a laxative effect but are often useful for issues like anxiety, insomnia, chronic stress, and inflammatory conditions. Some supplements provide a combination of different forms of magnesium to provide a range of potential benefits for the functioning of the brain, musculoskeletal, cardiovascular, gastrointestinal, and immune systems.

Bottom line: magnesium is a very safe mineral, and many people would benefit from increasing their daily intake of it. People with serious kidney disease are at risk for high levels of magnesium if they take it as a supplement. If you’re curious about this mineral, ask your health care provider if magnesium might be right for you.

In Good Health, James O'Keefe, MD, FACC