Magnesium keeps you strong and energised, yet most active women aren’t getting enough. Here are the best ways to increase your intake of this powerful muscle builder.

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Magnesium keeps you strong and energised, yet most active women aren’t getting enough. Here are the best ways to increase your intake of this powerful muscle builder. 

Long overlooked while calcium soaked up the spotlight, magnesium is finally getting some much-deserved attention from experts. Recent studies show that it 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 per cent of women don’t get enough,” says Liz Applegate, the director of sports nutrition at the University of California. “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 deficiency. “You lose magnesium through sweat, and if you work out regularly, those losses can add up,” Liz explains.

That’s a big problem because magnesium is crucial for health and fitness. “It plays an essential role in energy metabolism,” Liz 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 Dr Carolyn Dean, 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 mag nesium 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 500mg of magnesium chloride four times a day experienced an im provement in symptoms of depression and anxiety after just two weeks, the journal PLOS One found. 

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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,” Liz says. 

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


The recommended amount of magnesium is 310 to 320mg a day, but if you exercise heavily, you may need up to 600, Dr Dean says. A good rule of thumb: Increase your intake by about 100mg for every 45 minutes of exercise you get daily. If you still experience symptoms like chronic fatigue, muscle cramps, or anxiety, add another 50mg 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. 


“Green, leafy vegetables are a top source of magnesium – just eat them raw or lightly steamed to avoid losing too much nutrition,” Liz suggests. Other good sources: seeds, nuts, grains, and even cocoa. Choose raw spinach (135mg in 170g), dried pumpkin seeds (191mg in ¼ cup), almonds (108mg in ¼ cup), cocoa powder (107mg in ¼ cup), and cooked amaranth (160mg in a cup).

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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 the minerals 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, Liz says. But if you’re munching on a calcium- rich cheese platter, for instance, eat some pumpkin seeds or nuts with it. 


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 minimise any GI-related side effects. But aim to get no more than 50 per cent 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,” Liz says. 

Green, leafy vegetables are a top source of magnesium – just eat them raw or lightly steamed.