Get full access to Outside Learn, our online education hub featuring in-depth nutrition, fitness and adventure courses, and more than 2,000 instructional videos when you sign up for Outside+..
In the U.S. National Library of Medicine’s online database at pubmed.gov, there are more than five times as many scientific articles about calcium as there are about magnesium. Yet both are equally essential for the function of the human body.
Did you know?
The U.S. government didn’t start recommending minimum intakes of magnesium until 1968—27 years after issuing calcium recommendations.
These two minerals are somewhat like the opposite ends of a dimmer switch. Calcium gives bones their hardness and makes things happen by exciting nerves, contracting muscles, and contributing to the inflammation necessary to fight invaders or injury. Magnesium gives bones some flexibility, keeps them from becoming brittle, and has a “chilling out” effect, relaxing nerves and muscles and reducing inflammation. Calcium is necessary for blood to clot so that wounds can heal, while magnesium prevents harmful clots and keeps blood flowing.
When we experience a stressful situation, whether it’s an irritable boss, a traffic jam, or a workout at the gym, calcium contributes to the fight-or-flight response that kicks in, and if there isn’t enough magnesium to calm things down, we stay stressed. And without enough magnesium, high calcium levels can lead to stiff arteries and heart disease.
Reasons Why Magnesium is Essential
A natural component of every cell in the human body, magnesium is essential for more than 300 internal processes that go on all the time to sustain life, including energy production. A study of post-menopausal women tested performance on a stationary bike, before and after eating a low-magnesium diet, and found that lack of the mineral made a significant difference. With low magnesium, women used 10–15 percent more energy, and their heart rate increased by 10 beats per minute while doing the same amount of cycling. Magnesium can also improve sleep. In studies, other benefits of magnesium have included:
- Less risk of asthma
- Protection against type 2 diabetes
- Less depression
- Relief from symptoms of fibromyalgia
- Protection against hearing loss from very loud noise
- Lower blood pressure
- Fewer and shorter migraine headaches
- Relief from PMS
- Lower odds of irregular heart rhythm
- Less risk for osteoporosis
While lack of either mineral is bad for health, magnesium is the one likely to fall short because:
- Calcium is widely advertised as an essential nutrient.
- Calcium supplements are recommended by doctors.
- Calcium is added to many foods and drinks.
In comparison, magnesium doesn’t have a voice. Think about it: When was the last time you saw a TV commercial touting a food because it contains lots of magnesium?
The optimum ratio of calcium to magnesium is estimated to be 2:1 from all sources, including food and supplements, but in the average U.S. diet, it’s estimated to be 3:1, meaning too much calcium and too little magnesium.
Good sources of magnesium include leafy greens, nuts, whole grains, and legumes.
As an example, a half-cup of cooked spinach or 1 ounce of dry-roasted almonds contains about 80 mg of magnesium, which is around 20 percent of the daily minimum recommended amount.
Magnesium Deficiency Risk
A growing number of researchers, integrative physicians, and nutritionists consider the U.S. government-recommended amounts of magnesium to be too low. The current RDIs are 400–420 mg for most men and 320–360 mg for most women. However, many experts recommend up to 650 mg for women and 850 mg for men—and even as much as 1,000 mg for a man weighing 200 lb. or more.
Supplement Forms of Magnesium
Some forms of magnesium are more easily absorbed, including those labeled as “chelated,” and magnesium glycinate, malate, citrate, taurate, threonate, and orotate. Magnesium malate is often recommended to relieve symptoms of fibromyalgia, and magnesium threonate is sometimes formulated for brain health.
Magnesium can also be applied topically, as it is easily absorbed through the skin, such as with an Epsom salt bath or in a magnesium cream.
Be aware that taking more magnesium than the body can absorb can result in loose stools, and is more likely with the magnesium oxide form (the form used in laxatives).This problem is easily solved by reducing the dosage.