The Benefits of Magnesium

This important mineral can keep your heart healthy and your muscles strong

overhead view of wooden cutting board and knife with cut Swiss chard and some in colander
Swiss chard and other dark leafy greens are rich in magnesium.
Photo: Getty Images

Leafy greens, whole grains, nuts, and seeds. If you aren’t eating these foods regularly, your diet may be lacking in magnesium. In fact, nearly half of Americans fall short of their daily need for this mineral, according to the Department of Agriculture. Men should get 420 mg daily and women 320 mg.

Insufficient magnesium can have widespread consequences. “It is an essential nutrient needed for hundreds of biochemical reactions in the body,” says Anna Taylor, a registered dietitian at the Cleveland Clinic. “It helps regulate blood pressure, blood sugar, and heart rate while maintaining bone strength, and nerve and muscle function.”

How Magnesium Protects

“Most people will feel better and their health will improve if their magnesium intake is in an ideal range,” says James O’Keefe, MD, director of St. Luke’s Charles & Barbara Duboc Cardio Health & Wellness Center in Kansas City, Mo.

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Studies suggest that the mineral may protect against a number of ailments. A 2021 study in the journal Nutrients found that getting 320 mg of magnesium daily was associated with a 34 percent lower risk of cardiovascular disease compared with 240 mg a day. Another study, published in Nutrients in 2016, showed that the risk for type 2 diabetes dropped by 8 to 13 percent for every 100 mg consumed per day.

Magnesium may also lower fracture risk, improve muscle strength, and slow the advancement of sarcopenia, a loss of muscle mass that occurs with age. In addition, it’s important for immunity and is being studied, along with vitamin D, as a therapy to help patients fight COVID-19.

Magnesium supplements are often touted as a sleep aid, but whether they help and by how much is in question. In a 2021 review in BMC Complementary Medicine and Therapies, researchers looked at three studies involving older adults that compared magnesium with a placebo. They concluded that the studies provide “low to very low quality of evidence” of the mineral’s effect.

Minding Magnesium Intake

Magnesium deficiency can cause vague symptoms such as appetite loss, fatigue, weakness, and nausea. “That’s why we call it one of the great masqueraders,” says Liron Sinvani, MD, a geriatrician-hospitalist at the Feinstein Institutes for Medical Research in Manhasset, N.Y. Doctors can test only for levels in the blood, but that’s not a good indicator because only 1 percent of magnesium is found there. The rest is in bones and soft tissue.

So focusing on magnesium-rich foods is key. Though the mineral is found in many foods in small amounts, the best sources are beans, whole grains, nuts, and seeds. A few top sources:

• Pumpkin seeds: 1 oz., 156 mg
• Quinoa, cooked: 1 cup, 118 mg
• Edamame, frozen: 1 cup, 99 mg
• Almonds, dry roasted: 1 oz., 79 mg
• Spinach, cooked: 1⁄2 cup, 79 mg
• Swiss chard, cooked: 1⁄2 cup, 75 mg
• Kidney beans, canned: 1 cup, 69 mg
• 70%-85% dark chocolate: 1 oz., 65 mg
• Oatmeal, cooked: 1 cup, 63 mg
• Peanut butter: 2 Tbsp., 54 mg

If you take certain drugs, pay special attention to magnesium. Diuretics, proton pump inhibitors, bisphosphonates, and some antibiotics can lead to a deficiency, O’Keefe says. But supplements may not be the answer unless prescribed by a doctor. “They can actually do harm if they raise magnesium levels too high,” Sinvani says.

Editor’s Note: A version of this article also appeared in the March 2022 issue of Consumer Reports On Health.

Lori Loannou

Lori Ioannou

Lori Ioannou is an award-winning journalist who writes on health, consumer affairs, careers, small business, investing, and technology. She was the senior editor for special reports at CNBC and an executive editor at Time Inc.

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