Magnesium, which can be found in everything from plain yogurt to dark chocolate, is involved in plenty of processes in the body.
By Carolyn Todd– Allure.com
If you’ve found yourself browsing the supplement section of the drugstore lately, you may have come across bottles of magnesium tucked between the maca and the melatonin. But before you throw one in your basket in hopes of reaping some of the awesome benefits touted on the label, it’s important to understand what the stuff actually is, as well as what it can actually do for you.
Fortunately, we did the legwork and talked to an expert who helped us divide the fact from the myth. Here’s what you need to know about magnesium supplements and your health.
What is magnesium, and what does it do?
The quickest answer: A whole lot of important stuff. “Magnesium is all over the place in our body and involved in almost every system,” certified dietitian-nutritionist Gina Keatley tells Allure. In fact, she says, it plays a role in everything from cardiac health and metabolism to the quality of your sleep.
“You will find magnesium facilitating the creation of proteins, helping our nerves and muscles work, keeping our blood pressure in check and modifying blood glucose levels,” Keatley says. She adds that it also plays a part in helping to maintain a healthy heart rhythm.
Magnesium is an essential element in our bodies, especially when it comes to the creation and maintenance of bones. It’s even involved in the processes that allow us to create DNA, according to Keatley. Further, our metabolism relies on this important element. “We require magnesium to create energy from carbs, protein, and fats,” Keatley explains. Magnesium’s effects can be seen on the outside of the body, as well, where it is used to create strong bonds between proteins in the hair.
What are the common sources?
Fortunately, magnesium is present in a wide variety of foods we eat, including leafy greens, legumes, nuts, seeds, whole grains, and dairy, according to the National Institutes of Health (NIH). It’s also readily available in products specifically fortified with magnesium, like cereal.
Registered dietitian Amy Gannon, department manager of eCoaching at the Cleveland Clinic Wellness Institute, has a few top picks, including spinach, swiss chard, avocados, cashews, peanuts, almonds, quinoa, black beans, plain yogurt, and — those with a sweet tooth will be happy to hear — dark chocolate.
As with most nutrients, it’s ideal if you get your magnesium intake from these whole food sources, according to Gannon. That’s because these foods will not only provide you with magnesium, but a slew of other beneficial nutrients, including antioxidants, fiber, phytochemicals, and other vitamins and minerals vital to your health.
What’s the right dose for me?
“Most Americans do not get the recommended amount of magnesium per day,” Keatley says. Gannon adds that it varies based on gender, age, and life stage, but says, “For adults, the recommendation is 310 to 420 milligrams per day.” The NIH suggests most women aim for about 310 to 320 milligrams a day, although pregnant women may need a little more.
And though that may sound high if you’re not used to thinking about magnesium, it’s pretty easy to hit that dose if you’re eating the right foods. Gannon adds, “As a point of reference, one ounce of almonds contains about 80 milligrams.”
How can I tell if I’m magnesium deficient?
Not getting enough magnesium typically doesn’t result in any obvious side effects initially, because if that starts to happen the kidneys step in to keep the vast majority of our reserves up. “Only one to two percent of the magnesium in our bodies is in our blood with the rest kept highly regulated by the kidneys,” Gannon explains. “If we don’t get enough magnesium from outside sources […] our kidneys will restrict how much is excreted through urine. Because our bodies keep levels of magnesium in the blood so tightly controlled, true magnesium deficiency is not common.”
Over time, though, habitually low intakes and/or health issues — more on that in a minute — can lead to a true deficiency. This can cause negative side effects like fatigue, appetite loss, nausea, and vomiting. And in extreme cases, numbness, muscle cramping, and truly scary symptoms like heart rhythm abnormalities, seizures, and changes in personality can occur.
Unfortunately, there is no single reliable test for a magnesium deficiency. Assessing magnesium levels can be difficult because most of it is found inside of our cells or our bones. You can take a blood test, for example, but the NIH reports, “Serum levels have little correlation with total body magnesium levels or concentrations in specific tissues.”
That’s why experts warn that accurately diagnosing a deficiency requires both lab tests and a clinical assessment. If you’re having any of the symptoms described above, see your doctor in order to figure out what’s going on. Keep in mind, however, that there are quite a few things that could be causing those symptoms other than a magnesium deficiency. For instance, Lyme disease can also be a cause of fatigue, and fibromyalgia can lead to muscle cramping.
Who could see positive effects from taking magnesium?
In general, there are a few populations more likely to have a magnesium deficiency, like teenage girls and men over 70. “Some people are at more of a risk of chronically insufficient magnesium that could be problematic,” Gannon says. Those groups include:
- People with Type II diabetes: Gannon says that people with higher levels of blood sugar who urinate frequently may have chronic insufficiencies. Keatley agrees, adding “Many studies show the increased amount of sugar in the kidneys causes magnesium to escape.”
- People with GI issues: According to Gaston, gastrointestinal issues like a bowel resection, Crohn’s disease, or celiac disease can lead to higher magnesium losses.
- People with alcoholism or a binge-drinking habit: Due to a combination of factors including poor nutritional status, kidney stress, and gastrointestinal problems, Gannon says folks who drink more than average are at risk for magnesium deficiency and could benefit from supplementation.
- People of older age: As we get older, we tend to consume less magnesium, according to Gannon. Additionally, we experience decreased magnesium absorption in the small intestine as we age.
- People who have had heart failure or a heart attack: Magnesium can become depleted in these patients with heart failure or a history of heart attack, according to Keatley.
What are the major health benefits of this supplement?
Some research suggests that even if you aren’t in one of the categories that put you at higher risk for a deficiency, supplementation could have some positive effects on your health. “Magnesium has been studied in relation to conditions from asthma, clogged arteries, high cholesterol, diabetes, muscle cramps, and athletic performance, to name a few,” Gannon says, continuing, “Some research is more promising than others, but some have mixed results or are shown to be ineffective.”
The NIH cites research showing a possible association between high magnesium intake (from either food and supplementation) and a decreased risk of high blood pressure, heart disease, stroke, Type II diabetes, osteoporosis, and migraines. There is some evidence, for instance, suggesting that magnesium supplements may lower blood pressure by a small amount. In addition, there are also a few small studies showing they can reduce migraine frequency by a modest amount.
However, the NIH emphasizes that with all of these findings, we need more research to establish any kind of firm causal link. And because many studies (such as those on heart health) are looking at overall dietary magnesium intake as opposed to just supplementation, it’s difficult to assess how much of the effect is because of magnesium as opposed to other nutrients.
As Gannon puts it, “It could be the combination of the magnesium with the other benefits of those magnesium-rich foods,” meaning we can’t know whether supplements would have these same benefits. However, she points out that those food sources are still worth including.
Can magnesium supplements affect your sleep?
Another potential benefit of magnesium supplementation: better sleep. Not only does magnesium help lower stress by keeping your hormones in check and regulating your stress-response system, but it can lead to better sleep. In fact, insomnia is a common side effect of magnesium deficiency, and people who need more magnesium often experience many restless nights.
According to Healthline, the reason it helps some people sleep is that it “binds to gamma-aminobutyric acid (GABA) receptors. GABA is the neurotransmitter responsible for quieting down nerve activity.” In fact, Healthline also reports that GABA is the same exact neurotransmitter utilized by many common sleep drugs on the market, including Ambien.
I’m considering taking magnesium supplements. What are my next steps?
First and foremost, give the doc a ring. “Generally, adding magnesium-rich foods like fish and almonds to your diet is harmless,” Keatley says, but stresses that you should always talk to your doctor before starting (or changing) a supplementation routine. Gannon agrees, adding, “Your best bet is to talk with your doctor if you’re thinking [magnesium supplements] could help you.”
First, a physician can do a full medical history, physical exam, and order any necessary tests to help you figure out if there’s a serious underlying health issue going on. Second, a doctor can advise of any possible contraindications with regard to other health issues (like a kidney problem) or medications you’re taking. For example, magnesium can cause poor absorption of antibiotics and bisphosphonate (which are used to treat osteoporosis).
It could interact with other supplements you’re already taking too. “Iron and zinc fight for the same receptors in the intestine to enter the bloodstream, so if you’re taking iron, zinc, and magnesium at the same time you may be causing a big fight for space that results in deficiencies in all three,” Keatley explains.
If your doctor thinks you could benefit from supplementation, they can help point you in the right direction when it comes to choosing which one to take, because the number of options on the shelves can be overwhelming and confusing. In general, “Magnesium in the aspartate, citrate, lactate, and chloride forms are better absorbed than magnesium oxide and magnesium sulfate,” Keatley says, continuing, “So if you’re spending money on supplements you might as well get the best.”
And as for dosage, going above the maximum recommended amount for adults — 350 milligrams, according to the NIH — is a bad idea, because it can cause cramping, nausea, and diarrhea. Taking way too much can even cause an irregular heartbeat or heart attack.
But again, which form and dosage will benefit you varies from person to person, which is why you should seek your doctor’s advice. “Depending on why you are taking it might impact the dose and form of magnesium you take,” Gannon warns, “so be aware before going to the pharmacy and buying something without having that conversation.”