Magnesium keeps you strong and energized, yet most active women aren’t getting enough. Here are the best ways to increase your intake.

By Mirel Ketchiff
March 28, 2018
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Long overlooked while calcium soaked up the spotlight, magnesium is finally getting some much-deserved attention from experts. Recent studies show that magnesium helps boost muscle power, endurance, and sleep, all while reducing anxiety and even your cancer risk. But most of us are coming up short on this power mineral. "Roughly 75 percent of women don't get enough," says Liz Applegate, Ph.D., the director of sports nutrition at the University of California, Davis. "If you're eating less than 1,800 calories a day, avoiding grains, or not loading up on leafy greens, there's a good chance you're one of them." Surprisingly, exercise creates even more of a magnesium deficiency. "You lose magnesium through sweat, and if you work out regularly, those losses can add up," Applegate explains. (Related: 5 Minerals That Seriously Supercharge Your Workouts)

That's a big problem because magnesium is crucial for health and fit­ness. "It plays an essential role in energy metabolism," Applegate says. "Without it, your muscles can't get energy from the food you eat, leading to fatigue and lack of endurance." "Your muscles also need magnesium to function properly," adds Carolyn Dean, M.D., the author of The Magnesium Miracle, 2nd Edition. "It helps them take in oxygen, is necessary for maintaining electrolyte balance, and works with calcium to ensure that they contract and relax properly during activities." A mag­nesium deficiency can impair your ability to exer­cise, and it can also sap your z's. "Twitchy, tight mus­cles make you hyperalert and irritable, which can lead to trouble falling or staying asleep," Dr. Dean says.

Magnesium affects your mood too. Those of us who get more of the mineral are happier and more resil­ient to stress than others. In fact, study participants who took a supplement of 500 milligrams of magnesium chloride four times a day experienced an improvement in symptoms of depression and anxiety after just two weeks, PLOS One found.

Finally, studies show the metal may even help pre­vent certain types of cancer, including breast, ovarian, liver, colorectal, and pan­creatic. Here's how: When you're deficient in magne­sium, your body experiences oxidative stress, which pro­duces inflammation, a risk factor for cancer develop­ment and growth, the jour­nal Magnesium Research reports. Getting enough of the mineral keeps inflam­mation in check. "Not only that, but the foods that contain magnesium-leafy greens, nuts and seeds, whole grains-also tend to be amazing sources of phytonutrients that we know help lower breast cancer risk and improve digestive tract health," Applegate says. (Here's more on why magnesium is the micronutrient you should pay more attention to.)

The good news is that it takes just a few simple tweaks to boost your mag­nesium intake. Use this checklist to get fortified.

Figure Out Exactly How Much Magnesium You Need

The recommended amount of magnesium is 310 to 320 milligrams a day, but if you exercise heavily, you may need up to 600 milligrams, Dr. Dean says. A good rule of thumb: Increase your intake by about 100 milligrams for every 45 minutes of exercise you get daily. If you still experience symptoms like chronic fatigue, mus­cle cramps, or anxiety, add another 50 milligrams a day. (Increasing the amount by too much all at once can upset your stomach.) Repeat every one to two weeks until the symptoms go away. (Consult this fit woman's guide to getting enough calcium.)

Eat These Magnesium-Rich Foods

"Green, leafy vegetables are a top source of magnesium-just eat them raw or lightly steamed to avoid losing too much nutrition," Applegate suggests. Other good sources: seeds, nuts, grains, and even cocoa. Choose raw spinach (135 milligrams in six ounces), dried pumpkin seeds (191 in 1⁄4 cup), almonds (108 in 1⁄4 cup), cocoa powder (107 in 1⁄4 cup), and cooked amaranth (160 in a cup). (Try this superfood smoothie made with spinach and almond butter.)

Pair Magnesium with Calcium

Magnesium and calcium work as a team: Magnesium helps the body absorb calcium and relaxes the muscles, while calcium contracts them. But the two need to be in balance. Getting too much calcium and too little magnesium, which is relatively common for women, makes it harder for your body to use both nutrients effectively. That's why calcium and magnesium tend to come as a package deal in supplements. Getting enough magnesium will help keep things on an even keel. It's also important not to take in one nutrient without the other. Many healthy whole foods are good sources of both, including kale, almonds, and quinoa, Applegate says. But if you're munching on a calcium-rich cheese platter, for instance, eat some pumpkin seeds or nuts with it.

Fill In the Gaps with Magnesium Supplements

If you struggle to get enough magnesium from food alone, Dr. Dean says it's fine to take a supplement. Look for magnesium gluconate or magnesium chloride-they are less likely to cause stomach upset than magnesium oxide, according to, which tests the quality of supplements. Start with a low dosage so you can increase your daily intake slowly, and take it at night to minimize any GI-related side effects. But aim to get no more than 50 percent of your total magnesium intake from supplements. "Whole-food sources are best because they also contain zinc, copper, and other nutrients that all work together in the body," Applegate says.