Magnesium is an essential mineral that plays an important role in hundreds of your bodily functions, yet  almost half of people in the United States do not consume enough in their daily diet. “This can set the stage for more chronic diseases like diabetes, heart disease, high blood pressure and osteoporosis,” says Bethany M. Doerfler, MS, RDN, a clinical research dietitian at Northwestern Medicine Digestive Health Center.

Benefits of Magnesium

Found throughout your system — primarily in your bones, muscles and non-muscular soft tissue — magnesium is involved in:

• Muscle and nerve function
• Blood pressure regulation
• Blood sugar control
• Energy production
• Protein synthesis
• Bone density
• DNA repair

“Magnesium is part of a matrix of ‘helper nutrients’ like fiber, potassium and antioxidants, which protect blood vessels and improve insulin resistance,” says Doerfler.

Additionally, magnesium helps convert vitamin D into an active form for the body, and helps the liver and kidneys metabolize it. So, a deficiency in magnesium reduces your body’s ability to use vitamin D, which impacts your ability to absorb calcium.

Signs of Deficiency

Symptoms of magnesium deficiency can vary depending on the severity. “Severe deficiency is rare, but it can be seen in people taking certain acid-blocking medicines and in people with severe diarrhea and malnutrition,” explains Doerfler.

Some common signs and symptoms of mild to moderate deficiency include:

• Fatigue
• Loss of appetite
• Vomiting
• Weakness

Signs and symptom of extreme magnesium deficiency include:

• Numbness
• Tingling
• Muscle cramps
• Seizures
• Abnormal heart rhythm

“With magnesium, there aren’t overt deficiency syndromes, like scurvy, for example,” says Doerfler. “But a low-quality diet relative to magnesium has been implicated in a constellation of factors that increase the risk of cardiovascular disease and insulin resistance.”

If you are showing signs of deficiency, your physician may order a blood test.

Dietary Sources of Magnesium

The recommended daily allowance for magnesium varies by age and gender, but the standard amount is 320 milligrams (mg) for adult women and 420 mg for adult men. The best way to get enough magnesium is through your diet. Good sources of magnesium include:

• Dark leafy greens
• Nuts and seeds
• Whole grains
• Legumes
• Fish
• Yogurt
• Milk
• Fortified breakfast cereals

To help with you plan meals and snacks, here are some magnesium-rich foods along with the amount of magnesium they offer per serving:  

• Pumpkin seeds (1 ounce): 156 mg
• Chia seeds (1 ounce): 111 mg
• Almonds (1 ounce): 80 mg
• Spinach, boiled (1/2 cup): 78 mg
• Cashews (1 ounce): 74 mg
• Peanuts (1/4 cup): 63 mg
• Soy milk (1 cup): 61 mg
• Black beans, cooked (1/2 cup): 60 mg
• Dark chocolate (1 ounce): 50 mg
• Peanut butter (2 tablespoons): 49 mg
• Bread, whole wheat (2 slices): 46 mg
• Avocado, cubed (1 cup): 44 mg
• Brown rice, cooked (1/2 cup): 42 mg
• Banana (1 medium): 32 mg
• Rolled oats, cooked in unsalted water (100 grams): 29 mg
• Cow’s milk (1 cup): 24 mg

Drinking water can also contain magnesium, but the amount varies by type (tap, mineral or bottled/canned) and by brand. Check the nutrition label on bottled or canned water for magnesium levels.

“Getting adequate magnesium from your diet can be quick and easy if you layer magnesium-rich foods into each meal,” says Doerfler. She offers some ideas and swaps:

• Top Greek yogurt or cottage cheese with a 1/4 cup of pumpkin seeds.
• Snack on whole-grain fortified cereals that contain whole-grains oats or wheat as their first ingredient.
• Choose whole-grain and sprouted breads as a base for sandwiches, toast and snacks.
• Batch-cook chili with beans or add pre-cooked lentils to soups and stir fries to boost magnesium and protein.
• Choose chia seed puddings for dessert over ice cream.
• Add side salads with mixed greens and baby spinach to your lunch or dinner.

What About Supplements?

Food is a complex source of vitamins and minerals that work together in the body. Supplements tend to work in isolation. Because of this, it’s best to get your daily dose of magnesium from food sources.

“You don't get the same benefits from a magnesium supplement as you do from magnesium-rich foods in the diet,” says Doerfler. “Magnesium as part of the nutrient matrix is really what contributes the health benefits.”

If you are unable to get enough magnesium through your diet, you may need to take a supplement. It is important, however, to talk to your physician before taking any supplements, as they can interfere with certain medications.

Can You Get Too Much Magnesium?

If you are getting your magnesium from food and beverage sources, it’s unlikely you will get too much, says Doerfler. But, she warns that you can take too much in the form of supplements. “Separate and larger doses of magnesium can act like a laxative. Extremely high doses can lead to irregular heart rhythm,” she says.

To ensure you are getting enough magnesium for your body, incorporate magnesium-rich foods into your diet, and talk to your physician or a dietitian if you suspect you are deficient.